In Daniel Const. Co. v. Tolley, 24 Va. App. 70, 76, 480 S.E.2d 145, 148 (1997), the Court affirmed a finding by the commission that Tolley was entitled to total and permanent disability benefits for post-traumatic stress disorder resulting from a sudden dynamite explosion which occurred in the course of his employment. See 24 Va. App. at 77, 480 S.E.2d at 148. The commission relied upon the doctor's testimony that Tolley had suffered a severe brain injury and upon Tolley's medical records, which indicated that his injury had been consistently diagnosed since the time of the explosion. See id. at 77, 480 S.E.2d at 148-49. The doctor reported "that post-traumatic stress disorder results in irreversible structural changes within the neurons in the brain that include damage to neurosynaptic receptors and serotinergic neurotransmitters . . . and opined that such damage had occurred to Tolley's brain and that this injury impaired his cognitive abilities." Id. at 78, 480 S.E.2d at 149. Thus, "we held that the evidence was sufficient to prove that Tolley suffered an injury to his brain." 24 Va. App. at 77, 480 S.E.2d at 148.