"Decisions of the Board shall be based on the entire record in the proceedings and upon consideration of all evidence and material of record and applicable provisions of law and regulation." 38 U.S.C. § 7104(a); Schafrath v. Derwinski, 1 Vet. App. 589, 593 (1991); Weaver v. Principi, 14 Vet. App. 301, 302 (2001). The Board must include in its decision a written statement of the reasons or bases for its findings and conclusions on all material issues of fact and law presented on the record. That statement must be adequate to enable an appellant to understand the precise basis for the Board's decision and to facilitate informed review in this Court. See 38 U.S.C. § 7104(d)(1); Allday v. Brown, 7 Vet. App. 517, 527 (1995); Gilbert v. Derwinski, 1 Vet. App. 49, 56-57 (1990).
VA must consider "all the evidence of record that bears on occupational and social impairment," and then "assign a disability rating that most closely reflects the level of social and occupational impairment a veteran is suffering." See, e.g., Mauerhan v. Principi, 16 Vet. App. 436, 442 (2002). Section 7104(a) of title 38, United States Code, requires in pertinent part:
Decisions of the Board shall be based on the entire record in the proceeding and upon consideration of all evidence and material of record and applicable provisions of law and regulation.
38 C.F.R. section 3.303(a) similarly requires that "[d]eterminations as to service connection will be based on review of the entire evidence of record." 38 C.F.R. § 3.303(a) (emphasis added). Douglas v. Derwinski, 2 Vet. App. 435, 438 (1992). The Board's failure to consider and discuss specifically all of the evidence before it and the legal issue raised thereby is prejudicial error warranting a remand. See 38 U.S.C. § 7261(a)(3)(A). Douglas v. Derwinski, 2 Vet. App. 435, 440 (1992).
A VA examiner is presumed to have considered all the evidence in the record. Newhouse, 497 F.3d at 1302. The mere fact that the Board did not specifically discuss that opinion does not render the Board decision inadequate. Id. Further, an appellant must demonstrate that he or she was prejudiced by the Board's failure to discuss a particular piece of evidence. See Shinseki v. Sanders, 556 U.S. 396, 410 (2009) (appellant generally bears the burden of demonstrating prejudicial error on appeal).