Citation Nr: 1316485 Decision Date: 05/20/13 Archive Date: 05/29/13 DOCKET NO. 06-36 580 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in St. Louis, Missouri THE ISSUES 1. Entitlement to service connection for hypertension, to include as secondary to service-connected posttraumatic stress disorder (PTSD) and to include as a qualifying chronic disability under 38 C.F.R. § 3.317. 2. Entitlement to service connection for obstructive sleep apnea, to include as secondary to service-connected PTSD and chronic cough disorders and to include as a qualifying chronic disability under 38 C.F.R. § 3.317. 3. Entitlement to an initial disability rating greater than 10 percent for a chronic cough disability prior to October 11, 2006. 4. Entitlement to an initial disability rating greater than 30 percent for a chronic cough disability on or after October 11, 2006. REPRESENTATION Appellant represented by: Disabled American Veterans ATTORNEY FOR THE BOARD Paul S. Rubin, Counsel INTRODUCTION The Veteran had active duty service in the United States Army from January 1988 to January 1992 and from May 1987 to September 1987. He had service in the Southwest Asia Theater of Operations during the Persian Gulf War from January 1991 to May 1991. He also served in the Army Reserve from 1997 to 2002. This matter comes before the Board of Veterans' Appeals (Board) on appeal from March 2006 and June 2007 rating decisions issued by the Department of Veterans Affairs (VA) Regional Office (RO) in St. Louis, Missouri. The Board remanded the appeal in February 2010 and December 2011 for further development. The case has since been returned to the Board for appellate review. In the February 2010 and December 2011 Board decisions, the Board also adjudicated various other service connection issues that were previously on appeal. Thus, these issues are no longer on appeal before the Board. The Board also notes that the Veteran submitted additional medical and lay evidence in February 2013, which was after the certification of his appeal. However, he also provided a waiver of the RO's initial consideration of that evidence. Therefore, the Board has accepted this additional evidence for consideration at this time. See 38 C.F.R. §§ 20.800, 20.1304 (2012). A review of the Virtual VA paperless claims processing system does not reveal any additional documents pertinent to the present appeal. The issue of entitlement to service connection for obstructive sleep apnea is addressed in the REMAND portion of the decision below and is REMANDED to the RO via the Appeals Management Center (AMC), in Washington, DC. VA will notify the appellant if further action is required. FINDINGS OF FACT 1. The Veteran served in the Southwest Asia Theater of Operations during the Persian Gulf War period. 2. The Veteran did not have hypertension in service or for several years thereafter, and the evidence weighs against a nexus between the Veteran's current hypertension and his period of active service, to include his Persian Gulf War service. 3. The Veteran's hypertension was not caused or aggravated by his service-connected PTSD. 4. From January 24, 2005, to October 11, 2006, the Veteran's chronic cough disability was not productive of an FEV-1 of 56 to 70 percent of predicted value or worse; an FEV-1/FVC of 56 to 70 percent or worse; daily inhalational or oral bronchodilator therapy; inhalational anti-inflammatory medication; DLCO (SB) 56- to 65-percent predicted or worse; maximum oxygen consumption of 15 to 20 ml/kg/min (with cardiorespiratory limit) or worse; at least monthly visits to a physician for required care of exacerbations; intermittent (at least three per year) courses of systemic (oral or parenteral) corticosteroids; more than one attack per week with episodes of respiratory failure; required daily use of systemic (oral or parenteral) high dose corticosteroids or immune-suppressive medications 5. Since October 11, 2006, the Veteran's chronic cough disability has not been productive of an FEV-1 of 40 to 55 percent of predicted value or worse; an FEV-1/FVC of 40 to 55 percent or worse; DLCO (SB) of 40- to 55-percent predicted or worse; maximum oxygen consumption of 15 to 20 ml/kg/min (with cardiorespiratory limit) or worse; at least monthly visits to a physician for required care of exacerbations; intermittent (at least three per year) courses of systemic (oral or parenteral) corticosteroids; more than one attack per week with episodes of respiratory failure; required daily use of systemic (oral or parenteral) high dose corticosteroids or immune-suppressive medications; cor pulmonale (right heart failure); right ventricular hypertrophy; pulmonary hypertension (shown by Echo or cardiac catheterization); or, episode(s) of acute respiratory failure; or, the requirement for outpatient oxygen therapy CONCLUSIONS OF LAW 1. Service connection for hypertension on either a direct, presumptive, or secondary basis is not established. 38 U.S.C.A. §§ 1101, 1110, 1112, 1113, 1117, 1131, 1137, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.102, 3.159, 3.303, 3.307, 3.309, 3.310, 3.317 (2012). 2. From January 24, 2005, to October 11, 2006, the criteria for an initial disability rating higher than 10 percent for a chronic cough disability are not met. 38 U.S.C.A. §§ 1155, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.102, 3.159, 4.1-4.7, 4.20, 4.21, 4.27, 4.31, 4.96, 4.97, Diagnostic Codes 8866-6600 and 8866-6602 (2012). 3. On or after October 11, 2006, the criteria for an initial disability rating higher than 30 percent for a chronic cough disability are not met. 38 U.S.C.A. §§ 1155, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.102, 3.159, 4.1-4.7, 4.20, 4.21, 4.27, 4.31, 4.96, 4.97, Diagnostic Codes 8866-6600 and 8866-6602 (2012). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS VA's Duty to Notify and Assist Review of the claims folder reveals compliance with the Veterans Claims Assistance Act of 2000 (VCAA), 38 U.S.C.A. § 5100 et seq. See 38 C.F.R. §§ 3.102, 3.156(a), 3.159, 3.326(a). The duty to notify was accomplished by way of VCAA letters from the RO to the Veteran dated in May 2005, March 2006, June 2010, and December 2011. These letters satisfied the notification requirements of the VCAA consistent with 38 U.S.C.A. § 5103(a) and 38 C.F.R. § 3.159(b) by: (1) informing him about the information and evidence not of record that was necessary to substantiate his service connection, secondary service connection, and higher initial rating claims; (2) informing him about the information and evidence the VA would seek to provide; and (3) informing him about the information and evidence he was expected to provide. See also Pelegrini v. Principi, 18 Vet. App. 112 (2004) (Pelegrini II); Quartuccio v. Principi, 16 Vet. App. 183, 187 (2002). In addition, the March 2006 and December 2011 VCAA letters provided the Veteran with notice of the type of evidence necessary to establish a disability rating and effective date. Dingess v. Nicholson, 19 Vet. App. 473, 486 (2006); aff'd sub nom. Hartman v. Nicholson, 483 F.3d 1311 (2007). Moreover, the increased rating issue for a chronic cough arises from disagreement with the initial evaluation following the grant of service connection for the chronic cough disability in a March 2006 rating decision. Both the Court and the Federal Circuit Court of Appeals (Federal Circuit Court) have held that, once service connection is granted the claim is substantiated, additional VCAA notice is not required, and any defect in the notice is not prejudicial. Goodwin v. Peake, 22 Vet. App. 128, 137 (2008); Hartman v. Nicholson, 483 F.3d 1311 (Fed. Cir. 2007); Dunlap v. Nicholson, 21 Vet. App. 112 (2007). See also VAOPGCPREC 8-2003 (December 22, 2003). In summary, the Veteran has received all required VCAA notice in this case. With regard to the timing of notice, VCAA notice should be provided to a claimant before the initial unfavorable rating decision on a claim. Pelegrini II, 18 Vet. App. at 120 (2004). In the present case, the Board notes that the RO did not provide the Veteran with all VCAA notice prior to the March 2006 and June 2007 rating decisions on appeal. But in Pelegrini II, the Court also clarified that, in these situations, VA does not have to vitiate that decision and start the whole adjudicatory process anew, as if that decision was never made. Id. Rather, VA need only ensure the Veteran receives (or since has received) content-complying VCAA notice, followed by readjudication of his claims, such that he is still provided proper due process. In other words, he must be given an opportunity to participate effectively in the processing of his claims. The Federal Circuit Court has further held that a Statement of the Case (SOC) or Supplemental SOC (SSOC) can constitute a "readjudication decision" that complies with all applicable due process and notification requirements if adequate VCAA notice is provided prior to the SOC or SSOC. Mayfield v. Nicholson, 499 F.3d 1317, 1323 (Fed. Cir. 2007) (Mayfield IV). In fact, as a matter of law, VA may cure a timing of notice defect by taking proper remedial measures, such as issuing a fully compliant VCAA notice followed by readjudication, to include a SOC or SSOC. See also Prickett v. Nicholson, 20 Vet. App. 370, 376 (2006). In the instant case, the timing error was cured. After providing additional VCAA notice on multiple occasions, the RO readjudicated the claims in SSOCs, to include the most recent January 2013 SSOC. Thus, the timing defect in the notice has been rectified. Prickett, 20 Vet. App. at 376; see also Shinseki v. Sanders, 556 U.S. 396 (2009) (an error in VCAA notice should not be presumed prejudicial and the burden of showing harmful error rests with the party raising the issue, to be determined on a case-by-case basis). With respect to the duty to assist, the RO has obtained the Veteran's service treatment records, service personnel records, Army Reserve records, VA inpatient and outpatient treatment records, medical treatise evidence, and private medical evidence, as identified and authorized by the Veteran. For his part, the Veteran has submitted personal statements, lay statements from family and friends, argument from his representative, private medical evidence, and duplicate medical records. He has not identified any additional, outstanding evidence that is relevant to his claims being decided herein. The Veteran was also afforded VA examinations in September 2010, January 2012, and January 2013, and medical opinions were provided that addressed the etiology of his current hypertension on both a direct and secondary basis. See McLendon v. Nicholson, 20 Vet. App. 79, 81 (2006); see also 38 U.S.C.A. § 5103A(d)(2); 38 C.F.R. § 3.159(c)(4). As will be discussed below, when considered as a whole, these examinations and opinions were thorough, supported by explanations, based on a review of the claims folder, and supported by clinical evidence of record. As such, there is no basis for any further VA examination or opinion as to the hypertension issue on appeal. The January 2013 VA opinion, in particular, is wholly adequate. The Veteran was also afforded VA examinations in October 2005, June 2007, and January 2012 to ascertain the current severity of his chronic cough disability. The Board finds that the VA examinations obtained in this case are adequate, as they are predicated on a review of the claims file and all pertinent evidence of record as well as on a physical examination and fully address the rating criteria that are relevant to rating the disabilities in this case. These examinations included pulmonary function testing in evaluating his service-connected respiratory condition. The need for a more contemporaneous examination occurs only when the evidence indicates that the current rating may be incorrect or when the evidence indicates there has been a material change in the disability. See 38 C.F.R. § 3.327(a); Palczewski v. Nicholson, 21 Vet. App. 174, 182-83; VAOPGCPREC 11-95 (1995) (a new examination is appropriate when there is an assertion of an increase in severity since the last examination). The January 2012 VA examination is recent. Moreover, there is no suggestion that the current evidence is insufficient to evaluate the chronic cough disability. In this regard, the evidence of record does not establish that there has been a material change in the severity of the Veteran's service-connected disabilities beyond the 10 and 30 percent ratings currently assigned. Therefore, a new VA examination to rate the severity of his chronic cough disability is not warranted. With regard to the previous February 2010 and December 2011 Board remands, the Board finds that the RO/AMC substantially complied with the Board's remand directives. Stegall v. West, 11 Vet. App. 268, 271 (1998). See also D'Aries v. Peake, 22 Vet. App. 97, 105 (2008) (holding that only substantial compliance would be required, not strict compliance). Specifically, pursuant to the remands, the AMC provided additional corrective VCAA notice to the Veteran; secured additional VA and private treatment records; secured Army Reserve records; afforded the Veteran several VA examinations to determine the etiology of his hypertension on both a direct and secondary basis; and, afforded the Veteran several VA examinations to rate the current extent and severity of his service-connected chronic cough disability. As such, the RO has substantially complied with the Board's instructions. The Board is therefore satisfied that the RO has provided all assistance required by the VCAA. 38 U.S.C.A. § 5103A (West 2002 & Supp. 2012). Governing Laws and Regulations for Service Connection Veterans are entitled to compensation from the VA if they develop a disability "resulting from personal injury suffered or disease contracted in line of duty, or for aggravation of a preexisting injury suffered or disease contracted in line of duty." 38 U.S.C.A. § 1110 (wartime service), 1131 (peacetime service); 38 C.F.R. §§ 3.303, 3.306. In the absence of proof of a current disability, there can be no valid claim. Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000); Brammer v. Derwinski, 3 Vet. App. 223, 225 (1992). Under 38 C.F.R. § 3.303(a), service connection requires competent evidence showing: (1) the existence of a present disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the present disability and the disease or injury incurred or aggravated during service - the so-called "nexus" requirement. Holton v. Shinseki, 557 F.3d 1363, 1366 (Fed. Cir. 2009) (quoting Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004)). The Federal Circuit Court recently held that diseases that would be considered "chronic" in a medical sense, but which are not listed in 38 C.F.R. § 3.309(a) as an enumerated "chronic disease," may still qualify for service connection under the three-element test for disability compensation described in § 3.303(a). Walker v. Shinseki, 708 F.3d 1331, 1338-39 (Fed. Cir. 2013). Under 38 C.F.R. § 3.303(b), with an enumerated "chronic disease" (such as hypertension) shown in service (or within the presumptive period under § 3.307), subsequent manifestations of the same chronic disease at any later date, however remote, are service connected, unless clearly attributable to intercurrent causes. See also Groves v. Peake, 524 F.3d 1306, 1309 (2008). This rule does not mean that any manifestation of joint pain, any abnormality of heart action or heart sounds, any urinary findings of casts, or any cough, in service will permit service connection of arthritis, disease of the heart, nephritis, or pulmonary disease, first shown as a clear cut clinical entity, at some later date. For the showing of chronic disease in service there is required a combination of manifestations sufficient to identify the disease entity, and sufficient observation to establish chronicity at the time, as distinguished from merely isolated findings or a diagnosis including the word "Chronic." When the disease identity is established (leprosy, tuberculosis, multiple sclerosis, etc.), there is no requirement of evidentiary showing of continuity of symptomatology. 38 C.F.R. § 3.303(b). 38 C.F.R. § 3.303(b) also provides another route by which a Veteran can establish service connection for a "chronic disease" such as hypertension - by way of continuity of symptomatology. Continuity of symptomatology after discharge is required only where the condition noted during service (or in the presumptive period) is not, in fact, shown to be chronic or where the diagnosis of chronicity may be legitimately questioned, i.e., "when the fact of chronicity in service is not adequately supported." When the fact of chronicity in service is not adequately supported, then a showing of continuity after discharge is required to support a claim for disability compensation for the chronic disease. Proven continuity of symptomatology establishes the link, or nexus, between the current disease and serves as the evidentiary tool to confirm the existence of the chronic disease while in service or a presumptive period during which existence in service is presumed. 38 C.F.R. § 3.303(b). See also Walker, 708 F.3d at 1339-40. The Federal Circuit Court recently held that the regulation creating a presumption of service connection for "chronic diseases" manifesting during service or within one year of service, and then again at any later date (38 C.F.R. § 3.303(b)), is only available to establish service connection for the "chronic diseases" enumerated in 38 C.F.R. § 3.309(a) (listing named chronic diseases). Walker, 708 F.3d at 1336-37. In the same case, the Federal Circuit clarified that the continuity of symptomatology language in § 3.303(b) also "restricts itself to chronic diseases" found in 38 C.F.R. § 3.309(a). Id. at 1335. With respect to the current appeal, this list includes hypertension as an enumerated "chronic disease." See 38 C.F.R. § 3.309(a). Under 38 C.F.R. § 3.303(d), disorders diagnosed after discharge may still be service connected if all the evidence, including pertinent service records, establishes the disorder was incurred in service. See Combee v. Brown, 34 F.3d 1039, 1043 (Fed. Cir. 1994). As to presumptive service connection, some diseases are chronic, per se, such as hypertension, and therefore will be presumed to have been incurred in service, although not otherwise established as such, if manifested to a degree of ten percent or more within one year after service. The factual basis may be established by medical evidence, competent lay evidence, or both. Medical evidence should set forth the physical findings and symptomatology elicited by examination within the applicable period. Lay evidence should describe the material and relevant facts as to the Veteran's disability observed within such period, not merely conclusions based upon opinion. The chronicity and continuity factors outlined in § 3.303(b) will be considered. Even this presumption, however, is rebuttable by probative evidence to the contrary. 38 U.S.C.A. §§ 1101, 1112, 1113, 1137; 38 C.F.R. §§ 3.307, 3.309. Competent medical evidence means evidence provided by a person who is qualified through education, training, or experience to offer medical diagnoses, statements, or opinions. Competent medical evidence may also mean statements conveying sound medical principles found in medical treatises. It also includes statements contained in authoritative writings, such as medical and scientific articles and research reports or analyses. 38 C.F.R. § 3.159(a)(1). Competent lay evidence means any evidence not requiring that the proponent have specialized education, training, or experience. Lay evidence is competent if it is provided by a person who has knowledge of the facts or circumstances and conveys matters that can be observed and described by a lay person. 38 C.F.R. § 3.159(a)(2). In essence, lay testimony is competent when it regards the readily observable features or symptoms of injury or illness and "may provide sufficient support for a claim of service connection." Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007); Buchanan v. Nicholson, 451 F.3d 1331, 1336-37; Layno v. Brown, 6 Vet. App. 465, 469 (1994). The Federal Circuit has held that medical evidence is not always or categorically required in every instance to establish the required nexus or linkage between the claimed disability and the Veteran's military service. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. 2009). Lay evidence can also be competent and sufficient evidence of a diagnosis or to establish etiology if (1) the layperson is competent to identify the medical condition, (2) the layperson is reporting a contemporaneous medical diagnosis, or (3) lay testimony describing symptoms at the time supports a later diagnosis by a medical professional. Davidson, 581 F.3d at 1316. See also Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). In short, when considering whether lay evidence is competent the Board must determine, on a case by case basis, whether the Veteran's particular disability is the type of disability for which lay evidence may be competent on the issues of diagnosis and medical causation. Kahana v. Shinseki, 24 Vet. App. 428, 438 (2011). Lay evidence that is both competent and credible may establish the presence of a condition during service, post-service continuity of symptomatology, and a nexus between the present disability and the post-service symptomatology. Barr v. Nicholson, 21 Vet. App. 303, 307-09 (2007). But "[t]he type of evidence that will suffice to demonstrate entitlement to service connection, and the determination of whether lay evidence may be competent to satisfy any necessary evidentiary hurdles, depends on the type of disability claimed." Id. at 308. In determining whether service connection is warranted, the Board shall consider the benefit-of-the-doubt doctrine. 38 U.S.C.A. 5107(b); 38 C.F.R. § 3.102; Alemany v. Brown, 9 Vet. App. 518 (1996); Gilbert v. Derwinski, 1 Vet. App. 49 (1991). Governing Laws and Regulations for Persian Gulf Claims The law provides for compensation for Persian Gulf Veterans suffering from a chronic disability resulting from an undiagnosed illness or medically unexplained chronic multi-symptom illness that became manifest during active duty in the Southwest Asia theater of operations or became manifest to a compensable degree within the prescribed presumptive period. 38 U.S.C.A. § 1117; 38 C.F.R. § 3.317. That is, if not manifest in service, the claimed chronic disability must have been manifest to a degree of 10 percent or more by December 31, 2016. 38 C.F.R. § 3.317(a)(1)(i). See also 77 Fed. Reg. 63,225 - 63,227 (October 16, 2012) (final rule). A "Persian Gulf Veteran" is one who served in the Southwest Asia Theater of operations during the Persian Gulf War. See 38 C.F.R. § 3.317(e)(1). The Southwest Asia Theater of operations includes Iraq, Kuwait, Saudi Arabia, the neutral zone between Iraq and Saudi Arabia, Bahrain, Qatar, the United Arab Emirates, Oman, the Gulf of Aden, the Gulf of Oman, the Persian Gulf, the Arabian Sea, the Red Sea, and the airspace above these locations. 38 C.F.R. § 3.317(e)(2). In this case, the Veteran's service personnel records and DD Form 214 confirms that he served in the Southwest Asia Theater of operations from January 1991 to May 1991, for purposes of establishing the Veteran's status as a "Persian Gulf Veteran." 38 C.F.R. § 3.317(e). Effective March 1, 2002, and again October 7, 2010, the law affecting compensation for disabilities occurring in Persian Gulf War Veterans was amended. 38 U.S.C.A. §§ 1117, 1118. Per these changes, the term 'qualifying chronic disability' was revised to mean a chronic disability resulting from any of the following (or any combination of the following): (A) an undiagnosed illness; (B) a medically unexplained chronic multisymptom illness that is defined by a cluster of signs or symptoms, such as: (1) chronic fatigue syndrome; (2) fibromyalgia; (3) functional gastrointestinal disorders (excluding structural gastrointestinal diseases). 38 C.F.R. § 3.317(a)(2)(i). If probative evidence exists that the Veteran's disability pattern is either (1) an undiagnosed illness or (2) a diagnosable but medically unexplained chronic multisymptom illness of unknown etiology, including but not limited to, chronic fatigue syndrome, fibromyalgia, or functional gastrointestinal disorders, then service connection must be granted for a Gulf War illness. See 38 C.F.R. § 3.317(a)(2)(i) and (ii). For purposes of this presumption, the term "medically unexplained chronic multisymptom illness" means a diagnosed illness without conclusive pathophysiology or etiology, that is characterized by overlapping symptoms and signs and has features such as fatigue, pain, disability out of proportion to physical findings, and inconsistent demonstration of laboratory abnormalities. Chronic multisymptom illnesses of partially understood etiology and pathophysiology, such as diabetes and multiple sclerosis, will not be considered medically unexplained. 38 C.F.R. § 3.317(a)(2)(ii). Signs or symptoms which may be manifestations of an undiagnosed illness or medically unexplained chronic multi-symptom illness include, but are not limited to, cardiovascular signs or symptoms. 38 C.F.R. § 3.317(b). Compensation shall not be paid under 38 C.F.R. § 3.317 for a chronic disability: (1) if there is affirmative evidence that the disability was not incurred during active military, naval, or air service in the Southwest Asia theater of operations; or (2) if there is affirmative evidence that the disability was caused by a supervening condition or event that occurred between the Veteran's most recent departure from active duty in the Southwest Asia theater of operations and the onset of the disability; or (3) if there is affirmative evidence that the disability is the result of the Veteran's own willful misconduct or the abuse of alcohol or drugs. 38 C.F.R. § 3.317(a)(7). Governing Laws and Regulations for Secondary Service Connection In addition, a disability can be service-connected on a secondary basis if it is proximately due to or the result of a service-connected condition. 38 C.F.R. § 3.310(a). Moreover, secondary service connection may be established, as well, by any increase in severity (i.e., aggravation) of a nonservice-connected condition that is proximately due to or the result of a service-connected condition. 38 C.F.R. § 3.310(b), effective October 10, 2006. See 71 Fed. Reg. 52,744-52,747 (September 7, 2006). See also Allen v. Brown, 7 Vet. App. 439, 448 (1995); Tobin v. Derwinski, 2 Vet. App. 34, 39 (1991). Where a service-connected disability aggravates a nonservice-connected condition, a Veteran may be compensated for the degree of disability (but only that degree) over and above the degree of disability existing prior to the aggravation. Allen, 7 Vet. App. at 448. In short, in order to establish entitlement to service connection on this secondary basis, there must be (1) evidence of a current disability; (2) evidence of a service-connected disability; and (3) probative evidence establishing a nexus (i.e., link) between the service-connected disability and the current disability. Wallin v. West, 11 Vet. App. 509, 512 (1998). Analysis - Service Connection for Hypertension The Veteran has contended that it is "reasonable" to assume that his current hypertension began during his military service. He has stated he did not find out about having hypertension until several years after discharge from service in 1992. In the alternative, he has claimed that his hypertension is caused or aggravated by his service-connected PTSD. In this regard, he has asserted that PTSD heightens the effects of his high blood pressure and believes that there is a significant link between the two. See January 2009, May 2011, and January 2013 lay statements from the Veteran. When determining service connection, all theories of entitlement, direct and secondary, must be considered by the Board if raised by the evidence of record, applying all relevant laws and regulations. Szemraj v. Principi, 357 F.3d 1370, 1371 (Fed. Cir. 2004). Upon review of the evidence of record, the Board denies the appeal for service connection for hypertension on all bases - direct, presumptive, and secondary. The first and perhaps most fundamental requirement for any service-connection claim is proof the Veteran currently has the claimed disability. 38 U.S.C.A. §§ 1110, 1131; Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000); Brammer v. Derwinski, 3 Vet. App. 223, 225 (1992). Here, after a physical examination and blood pressure readings, the January 2012 VA hypertension examiner diagnosed the Veteran with hypertension. Earlier VA examinations, VA treatment records, and private treatment records dating back to 2000 also diagnosed the Veteran with hypertension. Thus, the evidence establishes that he currently has hypertension. The Veteran's service treatment records are negative for any complaints, treatment, or diagnoses of hypertension. He did not report any symptoms of hypertension during service, and predominantly, his blood pressure readings were not elevated during service. See 38 C.F.R. § 4.104, Diagnostic Code 7101, Note 1 (the term hypertension means that the diastolic blood pressure (i.e., bottom number) is predominantly 90 mm or greater, and isolated systolic hypertension means the systolic blood pressure (i.e., top number) is predominantly 160 mm or greater with a diastolic blood pressure of less than 90 mm). The Veteran chose not to take a separation examination. The Board has considered that the incurrence of an injury or disease alleged to have happened in combat may be shown by lay evidence, if consistent with the circumstances, conditions, or hardships of combat, even if there is no official record of the incident. 38 U.S.C.A. § 1154(b); 38 C.F.R. § 3.304(d). However, the Board finds no evidence of record or allegation from the Veteran that his hypertension was incurred during an incident of combat. Thus, the combat presumption does not assist him in the present case. Post-service, there is no probative evidence of hypertension within one year after the Veteran's separation from service in 1992. In fact, he even had a normal blood pressure reading of 100/70 in a private treatment record dated in July 1995. The first probative evidence of hypertension is contained in private treatment records dated in 1996, which assessed the Veteran as having high blood pressure. Therefore, the presumption of in-service incurrence for hypertension is not for application. 38 U.S.C.A. §§ 1101(3), 1112(a)(1), 1113, 1137; 38 C.F.R. §§ 3.307(a)(3), 3.309(a). Beginning four years after discharge from service, in May 1996, January 1997, and June 1997 private treatment records, consistent elevated blood pressure readings of 130/100, 134/110, 130/110, and 138/96 were recorded. The Veteran was advised about his "high" blood pressure, but he "refused to accept." Notably, an accompanying diagnosis of diabetes was also mentioned. VA treatment records document treatment for hypertension by way of medication in 2000 and thereafter. Under 38 C.F.R. § 3.303(b), this case does not meet the test for "chronic disease" as set forth in lieu of a medical nexus. Although hypertension is an enumerated "chronic disease" under 38 C.F.R. § 3.309(a) (listing named chronic diseases), hypertension in the present case is not "shown" in service. For the showing of chronic disease in service there is required a combination of manifestations sufficient to identify the disease entity, and sufficient observation to establish chronicity at the time, as distinguished from merely isolated findings or a diagnosis including the word "chronic." 38 C.F.R. § 3.303(b). The Veteran's service treatment records in the present case fail to establish a combination of manifestations sufficient to identify the disease entity of hypertension. That is, 38 C.F.R. § 3.303(b) equates "shown in service" with a reliable diagnosis of the chronic disease while in service. Walker, 708 F.3d at 1339. No such diagnosis of hypertension is of record during service. In addition, under 38 C.F.R. § 3.303(b), the probative evidence of record does not establish continuity of symptomatology for hypertension in lieu of medical nexus. When the fact of chronicity in service is not adequately supported, then a showing of continuity after discharge is required to support a claim for disability compensation for the chronic disease. Proven continuity of symptomatology establishes the link, or nexus, between the current disease and serves as the evidentiary tool to confirm the existence of the chronic disease while in service or a presumptive period during which existence in service is presumed. 38 C.F.R. § 3.303(b). With regard to continuity of symptomatology, in the present case, there is no probative lay or medical evidence of record establishing continuity of symptomatology for hypertension. The first evidence of hypertension in the claims folder after discharge is from private treatment records dated in 1996, which was approximately four years after discharge from service. Moreover, with regard to lay evidence, the Veteran is indeed competent to report purported symptoms of hypertension during and after service. See 38 C.F.R. § 3.159(a)(2); Barr, 21 Vet. App. at 307-09. However, the Veteran has not provided any specific lay description of hypertension symptoms during or immediately after discharge from service. He mentioned an intermittent history of headaches to the September 2010 VA examiner, but not specifically during service or immediately thereafter. It then follows that, in the instant case, there is no medical or lay basis to award service connection for his hypertension based on chronicity in service or continuous symptoms thereafter. 38 C.F.R. § 3.303(b). With regard to a nexus, there is probative medical evidence of record that clearly weighs against a relationship between the Veteran's present hypertension disability and his period of military service. Holton, 557 F.3d at 1366. See also 38 C.F.R. § 3.303(a), (d). Specifically, a January 2013 VA examiner reviewed the claims file, including the service treatment records, and noted that the Veteran was not diagnosed with hypertension until several years after service. The examiner opined that, although there were instances of elevated blood pressure readings during service, these readings were "less likely than not" indicative a "pre-hypertension" while on active duty. In so doing, the examiner cited to the Centers for Disease Control and Prevention (CDC) definition of hypertension and explained that the Veteran did not meet the specific criteria during service. The examiner also noted that the in-service readings were only single readings taken during examinations for minor injuries and common illnesses. Instead, she opined that the Veteran's hypertension was related to his "uncontrolled diabetic state" and his obesity. In so doing, she noted that his hypertension and diabetes began together after service. The examiner also cited to medical treatise evidence in support of her conclusion. Moreover, August 2009 medical treatise evidence in the claims folder also states that obesity can be associated with hypertension. Overall, this VA opinion was thorough, supported by an explanation, based on a review of the claims folder, and mostly supported by the evidence of record. Importantly, the Veteran has not submitted any contrary medical opinion of record with regard to hypertension. The Board acknowledges that, in September 2010, an earlier VA examiner assessed that hypertension "is less likely as not caused by or related" to service, as the Veteran was not diagnosed with hypertension until 1999 or 2000. A January 2012 VA examiner also rendered a similar conclusion. The January 2012 VA examiner added that the hypertension was not related to a specific exposure experienced by the Veteran in Southwest Asia. This VA examiner further stated that there are a known set of risk factors for hypertension, including familial disposition, increased body mass, and increasing age, and noted that one out of three adults in the United States has hypertension. However, both the September 2010 and January 2012 VA examination reports are entitled to limited probative value because both VA examiners noted that they did not review the Veteran's service treatment records in making their assessment. In this regard, one of the factors for assessing the probative value of a medical opinion is the physician's access to the claims file. Prejean v. West, 13 Vet. 444, 448-9 (2000). A clinician must be "informed of the relevant facts" and medical history in rendering a medical opinion. Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 304 (2008). In any event, the January 2013 VA opinion provides strong evidence against the nexus element of the hypertension claim. With regard to the Persian Gulf presumption, cardiovascular signs or symptoms are listed among the possible manifestations of an undiagnosed illness or medically unexplained chronic multi-symptom illness for purposes of presumptive service connection. 38 U.S.C.A. § 1117(g); 38 U.S.C.A. § 3.317(b)(11). However, in the present case, over the course of the appeal, the Veteran has received a clear diagnosis of hypertension. Therefore, the Veteran's symptoms are attributed to a known clinical diagnosis. See 38 C.F.R. § 3.317(a)(1)(ii). Moreover, because his hypertension is explained as due to obesity and diabetes mellitus, the associated disability is not "undiagnosed" or "medically unexplained" for purposes of applying the Persian Gulf presumption. 38 C.F.R. § 3.317(a)(2)(i) and (ii). In summary, presumptive service connection under 38 U.S.C.A. § 1117 and 38 C.F.R. § 3.317 is not warranted in this case. With regard to secondary service connection, the Board finds there is simply no probative evidence of record that the Veteran's service-connected chronic PTSD disability caused or aggravated a current hypertension disorder. 38 C.F.R. § 3.310(a), (b); Allen, 7 Vet. App. at 448; Tobin, 2 Vet. App. at 39. No medical professional of record has provided an opinion to support the Veteran's general assertions of secondary service connection. In fact, there is evidence weighing against a finding of secondary service connection. In particular, a January 2013 VA clinician opined that it was "less likely than not" that the Veteran's hypertension disability was caused by or aggravated by his service-connected PTSD. Instead, the VA clinician reasoned that the Veteran's hypertension was caused by, associated with, and aggravated by his diabetes and obesity. The January 2013 VA clinician cited medical treatise evidence in reaching her conclusions. Medical treatise evidence can provide important support when combined with an opinion of a medical professional. Mattern v. West, 12 Vet. App. 222, 228 (1999). See Rucker v. Brown, 10 Vet. App. 67, 73-74 (1997) (holding that evidence from scientific journal combined with doctor's statements was "adequate to meet the threshold test of plausibility"). The VA clinician also noted the Veteran's "volatile uncontrolled blood sugars" as a factor. The VA clinician added that she was unable to locate sufficient literature with scientific-based medical data for a nexus between PTSD and hypertension. The January 2013 VA examiner's opinion was detailed, thorough, based on a review of the pertinent evidence of record, and supported by adequate reasoning and medical treatise evidence. It provides strong medical evidence against secondary service connection for a hypertension disorder by way of proximate cause or aggravation. The Board finds that this unfavorable medical opinion is entitled to great probative weight against the claim. Significantly, there is no contrary medical opinion of record. With regard to lay evidence of a nexus of hypertension to service or a service-connected disability, lay persons are not categorically incompetent to speak on matters of medical diagnosis or etiology. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. 2009). In this vein, the Board must consider the type of condition specifically claimed and whether it is readily amenable to lay diagnosis or probative comment on etiology. See Woehlaert v. Nicholson, 21 Vet. App. 456, 462 (2007). The Veteran is indeed competent to report purported symptoms of hypertension, during and after service. See 38 C.F.R. § 3.159(a)(2); Barr, 21 Vet. App. at 307-09. However, the Veteran has not provided any specific lay description of hypertension symptoms during or immediately after discharge from service. In addition, as to the Veteran's lay assertions with regard to nexus, he also does not meet any of the three exceptions for competent lay evidence as listed under Jandreau. In any event, in the instant case, the Board finds the Veteran's lay statements regarding a nexus is less persuasive than the post-service VA medical opinions and medical treatise evidence linking his hypertension to his obesity and diabetes mellitus. Accordingly, the preponderance of the evidence is against the Veteran's service connection claim for hypertension on a direct, presumptive, and secondary basis. 38 U.S.C.A. § 5107; 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49 (1990). Governing Laws and Regulations for Increased Ratings Disability ratings are determined by applying the criteria set forth in VA's Schedule for Rating Disabilities (Rating Schedule), which is based on the average impairment of earning capacity. Individual disabilities are assigned separate diagnostic codes. 38 U.S.C.A. § 1155 (West 2002); 38 C.F.R. § 4.1 (2012). The basis of disability evaluations is the ability of the body as a whole, or of the psyche, or of a system or organ of the body to function under the ordinary conditions of daily life including employment. 38 C.F.R. § 4.10. If there is a question as to which evaluation to apply to the Veteran's disability, the higher evaluation will be assigned if the disability picture more nearly approximates the criteria for that rating. Otherwise, the lower rating will be assigned. 38 C.F.R. § 4.7. When reasonable doubt arises as to the degree of disability, such doubt will be resolved in the Veteran's favor. 38 C.F.R. § 4.3. Pertinent regulations do not require that all cases show all findings specified by the Rating Schedule, but that findings sufficiently characteristic to identify the disease and the resulting disability and coordination of rating with impairment of function. 38 C.F.R. § 4.21. Therefore, the Board has considered the potential application of various other provisions of the regulations governing VA benefits, whether or not they were raised by the Veteran, as well as the entire history of his disability in reaching its decision. Schafrath v. Derwinski, 1 Vet. App. 589, 595 (1991). VA regulation indicates that the Veteran's entire history is reviewed when assigning a disability evaluation per 38 C.F.R. § 4.1. Competent medical evidence means evidence provided by a person who is qualified through education, training, or experience to offer medical diagnoses, statements, or opinions. Competent medical evidence may also mean statements conveying sound medical principles found in medical treatises. It also includes statements contained in authoritative writings, such as medical and scientific articles and research reports or analyses. 38 C.F.R. § 3.159(a)(1). Competent lay evidence means any evidence not requiring that the proponent have specialized education, training, or experience. Lay evidence is competent if it is provided by a person who has knowledge of the facts or circumstances and conveys matters that can be observed and described by a lay person. 38 C.F.R. § 3.159(a)(2). In essence, lay testimony is competent when it regards the readily observable features or symptoms of injury or illness. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007); Buchanan v. Nicholson, 451 F.3d 1331, 1336-37; Layno v. Brown, 6 Vet. App. 465, 469 (1994). The Veteran has appealed the March 2006 rating decision that granted service connection for a chronic cough disability. This could result in "staged ratings" based upon the facts found during the period in question. See Hart v. Mansfield, 21 Vet. App. 505, 509-510 (2007); Fenderson v. West, 12 Vet. App. 119, 126 (1999). That is to say, the Board must consider whether there have been times since the effective date of his award when his disability has been more severe than at others. Id. In fact, in the present case, the RO has already staged the Veteran's chronic cough disability. From January 24, 2005, to October 11, 2006, the Veteran's chronic cough disability is rated as 10 percent disabling. As of October 11, 2006, the Veteran's chronic cough disability is rated as 30 percent disabling. (The 30 percent rating was based on a VA prescription list dated on October 11, 2006, that noted daily inhalational or oral bronchodilator therapy for the first time). The Veteran seeks disability ratings greater than 10 percent prior to October 11, 2006, and greater than 30 percent after October 11, 2006, for his chronic cough disability. The Veteran reports a continuing, daily cough that began in 1990 during his service in the Persian Gulf. He most recently indicates he has been on daily inhalational or oral bronchodilator therapy since 1990. See January 2013 Veteran's statement. Analysis - Rating Above 10 Percent for a Chronic Cough Prior to October 11, 2006, the Veteran's chronic cough is rated as 10 percent disabling by analogy under Diagnostic Code 8866-6602, bronchial asthma. 38 C.F.R. § 4.97 (2012). The disability was service-connected as a Persian Gulf undiagnosed illness. When an unlisted condition is encountered, it will be permissible to rate under a closely related disease or injury in which not only the functions affected, but the anatomical localization and symptomatology are closely analogous. 38 C.F.R. § 4.20. In addition, hyphenated diagnostic codes are used when a rating under one diagnostic code requires use of an additional diagnostic code to identify the specific basis for the evaluation assigned. 38 C.F.R. § 4.27. This purpose of the hyphenated diagnostic code in the present case (Diagnostic Code 8866-6602) is to establish that a Persian Gulf undiagnosed illness is the underlying service-connected disorder, and it is rated as if the residual condition is bronchial asthma. Respiratory disorders are rated under Diagnostic Codes 6600 through 6817 and 6822 through 6847. Ratings under those diagnostic codes will not be combined with each other. Rather, a single rating will be assigned under the diagnostic code which reflects the predominant disability with elevation to the next higher rating only where the severity of the overall disability warrants such elevation. 38 C.F.R. § 4.96(a) (2012). Diagnostic Codes 6600-6604 are classified under VA's Rating Schedule as Diseases of the Trachea and Bronchi. 38 C.F.R. § 4.97. The Board will consider Diagnostic Codes 6600 and 6602 as potentially applicable diagnostic codes in the present case pertaining to chronic bronchitis and bronchial asthma. In considering the applicability of other diagnostic codes, the Board finds that Diagnostic Codes 6601 (bronchiectasis), 6603 (pulmonary emphysema), and 6604 (chronic obstructive pulmonary disease) are not applicable in this instance, as the evidence does not show that the Veteran has been diagnosed with any of those conditions or anything similar. See September 2007 VA CT chest scan revealing no bronchiectasis; January 2012 VA respiratory examiner findings. Under Diagnostic Code 6602 for bronchial asthma, a 10 percent evaluation is warranted for an FEV-1 of 71 to 80 percent of predicted value, or, an FEV-1/FVC of 71 to 80 percent, or, intermittent inhalation or oral bronchodilator therapy. A 30 percent evaluation is warranted for an FEV-1 of 56 to 70 percent of predicted value, or, an FEV-1/FVC of 56 to 70 percent, or, daily inhalational or oral bronchodilator therapy, or, inhalational anti-inflammatory medication. A 60 percent evaluation is warranted for an FEV-1 of 40 to 55 percent of predicted value, or, an FEV-1/FVC of 40 to 55 percent, or, at least monthly visits to a physician for required care of exacerbations, or, intermittent (at least three per year) courses of systemic (oral or parenteral) corticosteroids. A maximum 100 percent disability rating is assigned for an FEV-1 less than 40 percent of the predicted value, or, FEV-1/FVC less than 40 percent, or, demonstrates more than one attack per week with episodes of respiratory failure, or, requires daily use of systemic (oral or parenteral) high dose corticosteroids or immune-suppressive medications. 38 C.F.R. § 4.97 (2012). Under Diagnostic Code 6600 for chronic bronchitis, a 10 percent rating is assigned for FEV-1 of 71- to 80-percent predicted value, or; the ratio of FEV-1/FVC of 71 to 80 percent, or; DLCO (SB) is 66- to 80-percent predicted. A 30 percent disability rating is assigned for FEV-1 of 56- to 70-percent predicted, or; FEV-1/FVC of 56 to 70 percent, or; DLCO (SB) 56- to 65-percent predicted. A 60 percent disability rating is assigned for FEV-1 of 40- to 55-percent predicted, or; FEV-1/FVC of 40 to 55 percent, or; DLCO (SB) of 40- to 55-percent predicted, or; maximum oxygen consumption of 15 to 20 ml/kg/min (with cardiorespiratory limit). Finally, a maximum 100 percent disability rating is assigned for FEV-1 less than 40 percent of predicted value, or; FEV-1/FVC less than 40 percent, or; DLCO (SB) less than 40-percent predicted, or; maximum exercise capacity less than 15 ml/kg/min oxygen consumption (with cardiac or respiratory limitation), or; cor pulmonale (right heart failure), or; right ventricular hypertrophy, or; pulmonary hypertension (shown by Echo or cardiac catheterization), or; episode(s) of acute respiratory failure, or; requires outpatient oxygen therapy. Id. Effective October 6, 2006, VA added provisions that clarify the use of pulmonary function tests (PFTs) in evaluating respiratory conditions. See 71 Fed. Reg. 52459 (Sept. 6, 2006) (codified at 38 C.F.R. § 4.96(d)). That is, 38 C.F.R. § 4.96(d) was added to the Rating Schedule, applicable to all applications for benefits received by VA on or after October 6, 2006. In the present case, the Veteran filed his initial rating claim in January 2005, prior to effective date of the change. Therefore, the amendments are inapplicable to his claim. Regardless, the regulation change, effective October 2006, did not alter any of the specific criteria listed under 38 C.F.R. § 4.97, Diagnostic Codes 6600 and 6602, for chronic bronchitis and bronchial asthma. Rather, the new regulation affected how the evaluation criteria were applied, including when a PFT is required to evaluate the disability, when to apply pre-bronchodilator values for rating purposes, and which PFT result to use (FEV-1 versus FEV-1/FVC versus DLCO (SB)) when the level of evaluation would differ depending on the test used. Significantly, both prior to and after the above amendments, post-bronchodilator findings for PFTs are the standard in pulmonary assessment. See 61 Fed. Reg. 46,720, 46,723-29 (Sept. 5, 1996) (the results of testing following optimum therapy reflect the best possible functioning of an individual and are the figures used as the standard basis of comparison of pulmonary function.). However, if the post-bronchodilator results are poorer than the pre-bronchodilator results, then the pre-bronchodilator results are used for rating purposes. See 38 C.F.R. § 4.96(d)(5) (2012). From January 24, 2005, to October 11, 2006, a review of the evidence of record does not support a disability rating greater than 10 percent for the Veteran's chronic cough disability. 38 C.F.R. § 4.7. The evidence of record does not show that the Veteran met the criteria necessary for a higher rating. In particular, he did not have an FEV-1 of 56 to 70 percent of predicted value or worse; an FEV-1/FVC of 56 to 70 percent or worse; daily inhalational or oral bronchodilator therapy; inhalational anti-inflammatory medication; DLCO (SB) 56- to 65-percent predicted or worse; maximum oxygen consumption of 15 to 20 ml/kg/min (with cardiorespiratory limit) or worse; at least monthly visits to a physician for required care of exacerbations; intermittent (at least three per year) courses of systemic (oral or parenteral) corticosteroids; more than one attack per week with episodes of respiratory failure; or, required daily use of systemic (oral or parenteral) high dose corticosteroids or immune-suppressive medications. See again 38 C.F.R. § 4.97, Diagnostic Codes 6600 and 6602. In making this determination, the Board has considered VA treatment records with PFT studies dated from 2000 to 2006, an October 2005 VA respiratory examination, private treatment records, and the Veteran's lay discussion of his symptoms. Specifically, VA pulmonary notes dated in 2004 and 2005 indicate that the Veteran reported a persistent, chronic cough present since the 1991 Persian Gulf War. He was provided one course of prednisone corticosteroids in 2004, but no further courses. This course was not successful. There was no indication of daily inhalational or oral bronchodilator therapy; or, inhalational anti-inflammatory medication. VA PFTs dated in June 2004 only demonstrated a FEV-1 of 100 percent predicted (pre-bronchodilator) and a FEV-1/FVC ratio of 80 percent (pre-bronchodilator). There were no post-bronchodilator findings. VA PFTs dated in August 2004 revealed a FEV-1 of 97 percent predicted (pre-bronchodilator) and a FEV-1/FVC ratio of 83 percent (pre-bronchodilator). There were no post-bronchodilator findings. An October 2005 VA examination with PFTs documented a FEV-1 of 76 percent predicted (post-bronchodilator); a FEV-1/FVC ratio of 82 percent (post-bronchodilator); and, a DLCO (DB) of 114 percent predicted (pre-bronchodilator). A September 2006 VA prescription list, (and all earlier VA prescription lists contained in the record), failed to document any inhalational or oral bronchodilator therapy or any inhalational anti-inflammatory medication. Prior to October 11, 2006, the Veteran, as a lay person, has competently and credibly reported respiratory symptomatology, such as severe coughing, sputum, and shortness of breath, among other symptoms. In a January 2013 statement, the Veteran also alleged that he has been on albuterol oral inhibitor on a daily basis since 1991, which would entitle him to a higher 30 percent rating. In increased rating claims, a Veteran's lay statements alone, absent a negative credibility determination, may constitute competent evidence of worsening, at least with respect to observable symptoms. See Vazquez-Flores v. Shinseki, 24 Vet. App. 94, 102 (2010), rev'd on other grounds by Vazquez-Flores v. Shinseki, 580 F.3d 1270, 1277 (Fed. Cir. 2009). The Board finds that the lay evidence of record from the Veteran is competent. However, such descriptions of this disability must be considered in conjunction with the clinical evidence of record and the pertinent rating criteria. Once evidence is determined to be competent, the Board must determine whether such evidence is also credible and probative. See Barr v. Nicholson, 21 Vet. App. 303, 310 (2007). As to credibility, contrary to the Veteran's assertions, VA treatment records dated prior to October 2006 do not reveal a daily prescription for albuterol, inhalational or oral bronchodilator therapy, or inhalational anti-inflammatory medication. They document other prescriptions, but not these particular respiratory medications. Moreover, no private records document the use of inhalational medication prior to October 2006. In other words, the Veteran's lay assertion regarding the daily use of albuterol prior to October 2006 is unsupported by all other evidence of record, and such medication would have required a prescription. Notably, VA pulmonary notes dated in 2004 and 2005 discussed the Veteran's history of a chronic cough, but were entirely silent as to the use of inhalational or oral bronchodilator therapy at that time. These records are more persuasive than the Veteran's subsequent lay assertions. See Rucker v. Brown, 10 Vet. App. 67, 73 (1997) (stating that reports made for the purposes of medical treatment may be afforded greater probative value because there is a strong motive to tell the truth in order to receive proper care). The credibility factors of the Veteran's interest and bias come into play here. Caluza v. Brown, 7 Vet. App. 498, 510-511 (1995), aff'd per curiam, 78 F.3d 604 (Fed. Cir. 1996). Therefore, based on the above evidence, prior to October 11, 2006, the Board finds that the overall disability picture for this time period more closely approximates the criteria for a 10 rating. 38 C.F.R. § 4.7. The Board has also considered application of Diseases of the Nose and Throat (Diagnostic Codes 6502 to 6524); Diseases of the Lungs and Pleura such as Tuberculosis (Diagnostic Codes 6701 to 6732); Nontuberculous Diseases (Diagnostic Codes 6817 to 6820); Bacterial Infections of the Lung (Diagnostic Codes 6822-6824); Interstitial Lung Disease (Diagnostic Codes 6825-6833); Mycotic Lung Disease (Diagnostic Codes 6834-6839); and Restrictive Lung Disease (Diagnostic Codes 6840-6847). See 38 C.F.R. § 4.97. However, the Veteran is not service-connected for any of these respiratory disorders, and the evidence of record does not reveal any diagnoses for these disorders. Therefore, these alternative diagnostic codes will not be applied for the service-connected chronic cough disability. See Butts v. Brown, 5 Vet. App. 532, 538 (1993) (choice of diagnostic code should be upheld if it is supported by explanation and evidence). Diagnostic Codes 6600 and 6602 for chronic bronchitis and bronchial asthma are clearly the most appropriate diagnostic codes for rating the Veteran's chronic cough disability. In summary, prior to October 11, 2006, the preponderance of the evidence is against an initial disability rating greater than 10 percent for a chronic cough disability. 38 C.F.R. § 4.3. Analysis - Rating Above 30 Percent for a Chronic Cough From October 11, 2006, to the present, the Veteran's chronic cough disability is rated as 30 percent disabling. (The 30 percent rating was based on a VA prescription list dated on October 11, 2006, that noted daily inhalational or oral bronchodilator therapy for the first time). A review of the evidence of record does not support a disability rating greater than 30 percent for the Veteran's chronic cough disability on or after October 11, 2006. 38 C.F.R. § 4.7. The Veteran has not been shown to have an FEV-1 of 40 to 55 percent of predicted value or worse; an FEV-1/FVC of 40 to 55 percent or worse; DLCO (SB) of 40- to 55-percent predicted or worse; maximum oxygen consumption of 15 to 20 ml/kg/min (with cardiorespiratory limit) or worse; at least monthly visits to a physician for required care of exacerbations; intermittent (at least three per year) courses of systemic (oral or parenteral) corticosteroids; more than one attack per week with episodes of respiratory failure; required daily use of systemic (oral or parenteral) high dose corticosteroids or immune-suppressive medications; cor pulmonale (right heart failure); right ventricular hypertrophy; pulmonary hypertension (shown by Echo or cardiac catheterization); episode(s) of acute respiratory failure; or, the requirement for outpatient oxygen therapy. See again 38 C.F.R. § 4.97, Diagnostic Codes 6600 and 6602. In making this determination, the Board has considered VA treatment records dated from 2006 to 2013, VA respiratory examinations with PFT testing dated in June 2007, September 2010, and January 2012, and the Veteran's lay discussion of his symptoms. Specifically, a VA prescription list dated on October 11, 2006, noted daily inhalational or oral bronchodilator therapy for the first time. VA treatment notes dated in April 2007 and January 2013 document that the Veteran was provided short courses of prednisone corticosteroids, but there is no evidence of any further courses. As relevant as to whether the Veteran can receive a higher 60 percent rating, there is no indication of at least three per year courses of systemic (oral or parenteral) corticosteroids. The January 2012 VA respiratory examiner also noted no use of (oral or parenteral) corticosteroids at that time. The June 2007 VA respiratory examiner noted the use of albuterol inhalers and steroids in the past year. There was no improvement in the Veteran's cough. PFTs only demonstrated a FEV-1 of 74 percent predicted (post-bronchodilator); a FEV-1/FVC ratio of 82 percent (post-bronchodilator); and, a DLCO (DB) of 85 percent predicted (pre-bronchodilator). There was good patient effort and cooperation. A September 2007 VA pulmonary note revealed a PFT demonstrating a FEV-1 of 75 percent predicted and a FEV-1/FVC ratio of 95 percent. It is unclear whether these findings were pre-bronchodilator or post-bronchodilator. The September 2010 VA respiratory examiner noted that the Veteran used his albuterol inhaler four times a day at that time. However, the Veteran failed to appear for PFT testing at that time. The January 2012 VA respiratory examiner noted that the Veteran did not exhibit any relief with steroid inhalers. At present, there was no use of oral or parenteral corticosteroid medications. The Veteran did utilize intermittent inhalational bronchodilator therapy, but he did not require antibiotics or oxygen therapy. The Veteran's condition did not result in cor pulmonale (right heart failure), right ventricular hypertrophy, or pulmonary hypertension. The VA examiner referenced VA PFT results from February 2011. These PFTs only demonstrated a FEV-1 of 86 percent predicted (post-bronchodilator) and a FEV-1/FVC ratio of 84 percent (post-bronchodilator). There was no significant change with the use of a bronchodilator, and no limitation of pulmonary function was found. A diagnosis of idiopathic refractive cough was assessed without abnormal pathology. After October 11, 2006, the Veteran, as a lay person, has competently and credibly reported respiratory symptomatology, such as severe coughing, sputum, and shortness of breath, among other symptoms. In increased rating claims, a Veteran's lay statements alone, absent a negative credibility determination, may constitute competent evidence of worsening, at least with respect to observable symptoms. See Vazquez-Flores v. Shinseki, 24 Vet. App. 94, 102 (2010), rev'd on other grounds by Vazquez-Flores v. Shinseki, 580 F.3d 1270, 1277 (Fed. Cir. 2009). However, none of this confirmed symptomatology establishes a higher rating above 30 percent under 38 C.F.R. § 4.97, Diagnostic Codes 6600 and 6602, for the chronic cough disability. Accordingly, the Board concludes that the evidence does not support an initial disability rating above 30 percent for the Veteran's chronic cough disability from October 11, 2006, to the present. 38 C.F.R. § 4.3. Fenderson Consideration It is not necessary to "stage" the Veteran's ratings any further, as his respiratory symptoms attributable to his service-connected chronic cough have been consistent at the 10 percent and 30 percent levels for their respective time periods. Fenderson, 12 Vet. App. at 126. Extra-Schedular Consideration Finally, there is no evidence of exceptional or unusual circumstances to warrant referring the case for extraschedular consideration for the chronic bronchitis disability. 38 C.F.R. § 3.321(b)(1). Initially, the Board does acknowledge that some of the respiratory manifestations of his chronic bronchitis disability are not specifically listed by the rating criteria under Diagnostic Codes 6600 and 6602. Thun v. Peake, 22 Vet. App. 111, 115-116 (2008). In any event, to the extent the rating criteria do not cover all his symptomatology, the Board finds insufficient evidence that the Veteran's chronic bronchitis disability markedly interferes with his ability to work, meaning above and beyond that contemplated by his 10 and 30 percent schedular ratings. As noted above, the degrees of disability specified in the Rating Schedule are considered adequate to compensate for considerable loss of working time from exacerbations or illnesses proportionate to the severity of the several grades of disability. 38 C.F.R. § 4.1; VAOPGCPREC 6-96. See also, Bagwell v. Brown, 9 Vet. App. 337, 338 (1996); Shipwash v. Brown, 8 Vet. App. 218, 227 (1995). The Veteran works full-time as a service representative at the Social Security Administration (SSA). The Board acknowledges that there is documentation that the Veteran on occasion misses time from work due to symptoms of his service-connected chronic cough disability. See e.g., June 2007 VA examination; August 2007 VA treatment record; September 2010 VA examination. However, some interference with employment is already contemplated by the 10 and 30 percent disability ratings that are assigned for the Veteran's chronic cough disability. See 38 U.S.C.A. § 1155; 38 C.F.R. § 4.1. Thus, overall, the evidence of record fails to demonstrate "marked" interference with employment from the chronic cough disability. 38 C.F.R. § 3.321(b)(1). Finally, there is no evidence of any other exceptional or unusual circumstances, such as frequent hospitalizations due to the Veteran's service-connected chronic cough disability, to suggest he is not adequately compensated for his disability by the regular Rating Schedule. 38 C.F.R. § 3.321(b)(1); VAOPGCPREC 6-96. The majority of his post-service evaluation and treatment for his chronic cough has been on an outpatient basis. He has not been frequently hospitalized due to his chronic cough disability. The Board is aware of the Court's recent holding that VA's disability-by-disability interpretation of § 3.321(b)(1) was consistent with its statutory and regulatory scheme. Johnson v. Shinseki, No. 10-1785 (Vet. App. Mar. 27, 2013). Thus, the Board does not have to consider the Veteran's multiple service-connected disabilities on a collective basis when determining whether an extraschedular referral is warranted here. ORDER Service connection for hypertension, to include as secondary to service-connected PTSD, is denied. Prior to October 11, 2006, an initial disability rating greater than 10 percent for a chronic cough disability is denied. On or after October 11, 2006, an initial disability rating greater than 30 percent for a chronic cough disability is denied. REMAND The Board finds that additional development of the evidence is required for the issue of entitlement to service connection for sleep apnea. The Court has held "that a remand by this Court or the Board confers on the veteran or other claimant, as a matter of law, a right to compliance with the remand orders." Stegall v. West, 11 Vet. App. 268, 271 (1998). As such, compliance with the terms of the remand is necessary prior to further appellate review, and if not, "the Board itself errs in failing to ensure compliance." Id. In this case, the Board previously remanded the sleep apnea issue for further development, to include obtaining a medical opinion. Specifically, the RO requested that the examiner indicate whether it is at least as likely as not that the Veteran's currently diagnosed sleep apnea manifested in service or is otherwise causally or etiologically related to his military service. He or she was also asked to state whether it is at least as likely as not that that the Veteran currently has sleep apnea that is either caused by or permanently aggravated by his service-connected chronic cough or PTSD, including the medications taken for treatment of each disability. It was noted that the Veteran had contended that his medications for the service-connected disabilities caused his obesity, which in turn, led to his sleep apnea. Following the remand, the Veteran was provided a VA examination in January 2012, and the examiner discussed whether his current sleep apnea was etiologically related to his military service. However, the examiner did not adequately address the theory of secondary service connection. Specifically, the examiner only discussed whether sleep apnea was secondary to the chronic cough, but failed to address whether sleep apnea was secondary to PTSD. In addition, the VA examiner did not discuss the Veteran's theory that his medications for the service-connected disabilities caused his obesity, which in turn, led to his sleep apnea. When VA undertakes to provide a VA examination or obtain a VA opinion, it must ensure that the examination or opinion is adequate. Barr v. Nicholson, 21 Vet. App. 303, 312 (2007). Therefore, the Board finds that a clarifying medical opinion is necessary. Accordingly, the service connection issue for obstructive sleep apnea is REMANDED for the following action: 1. The RO/AMC should obtain any outstanding treatment records from the VAMC in Atlanta, Georgia dated since January 2013. All attempts to secure these records, and any response received, should be documented in the claims file. If no records are available, a response to that effect is required and should be documented in the file. 2. After securing any VA or private treatment records, the RO/AMC should refer the Veteran's claims folder to the January 2012 VA sleep apnea examiner or, if he is unavailable, to another suitably qualified VA examiner for a clarifying VA addendum opinion as to the nature and etiology of the Veteran's sleep apnea. The examiner is requested to review all pertinent records associated with the claims file, including the Veteran's service treatment records, post-service medical records, and assertions. The examiner should state whether it is at least as likely as not (i.e., 50 percent or more probable) that the current sleep apnea disorder is caused or aggravated by the Veteran's service-connected chronic cough and PTSD disabilities. The examiner should also specifically address whether the medications taken for the treatment of his service-connected chronic cough and PTSD disabilities have caused or aggravated his sleep apnea. (The term "at least as likely as not" does not mean within the realm of medical possibility, but rather that the medical evidence both for and against a conclusion is so evenly divided that it is as medically sound to find in favor of conclusion as it is to find against it.) A clear rationale for the opinion is required, and a discussion of the facts and medical principles involved would be of considerable assistance to the Board. 3. The RO/AMC should then review the claims file and ensure that all of the foregoing development actions have been conducted and completed in full. If any development is incomplete, appropriate corrective action is to be implemented. If any report does not include adequate responses to the specific opinions or testing requested, it must be returned to the examiner for corrective action. See Stegall v. West, 11 Vet. App. 268, 271 (1998). 4. Thereafter, the RO/AMC should consider all of the evidence of record and readjudicate the remaining issue on appeal of service connection for obstructive sleep apnea. If the benefit sought is not granted, the RO/AMC should issue a Supplemental Statement of the Case and allow the Veteran and his representative an opportunity to respond. Thereafter, if indicated, the case should be returned to the Board for the purpose of appellate disposition. No action is required of the Veteran until he is otherwise notified by the RO/AMC. By this action, the Board intimates no opinion, legal or factual, as to any ultimate disposition warranted in this case. The appellant has the right to submit additional evidence and argument on the matter or matters the Board has remanded. Kutscherousky v. West, 12 Vet. App. 369 (1999). This claim must be afforded expeditious treatment. The law requires that all claims that are remanded by the Board of Veterans' Appeals or by the United States Court of Appeals for Veterans Claims for additional development or other appropriate action must be handled in an expeditious manner. See 38 U.S.C.A. §§ 5109B, 7112 (West Supp. 2012). ______________________________________________ JESSICA J. WILLS Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs