The veteran was interviewed in August 1965 as part of a social and industrial survey. At this time he stated he had been a sergeant in command of a unit and had had a strong, firm voice and had won many commendationsfor his command before he was exposed to radiation; that after his radiation .exposure he was hospitalized about 13 months; and thereafter he was relieved of his command and given technical work to do until he retired. He said that the first sign of radiation damage was a rash on his neck and arms; that he was treated for this and was ordered to be evacuated; that while he was awaiting transportation the joints of his knees, ankles and elbows became swollen; that while he was hospitalized his speech began to take on the present characteristics; that his inability to speak clearly had grown worse; that he continued to have difficulty with a skin rash, once a year, generally during the summer, that the rash had been present on his scalp, as well as on his arnts and neck; and that he also suffered from chronic headaches, which were worse when the rash was present. From other sources interviewed in the course of the survey, information was obtained that drinking had been a problem for the veteran for a number of years. In August 1965 the veteran was admitted to a hospital for a period of examination and observation. Physical examination was not remarkable and laboratory findings were within normal limits. Skull X-ray studies disclosed no evidence of old or new fracture or of any other abnormality. An electroencephalogram was normal, Neuropsychiatric examination and psychological testing revealed that he was cooperative, oriented, coherent and relevant. His speech was slow and difficult to understand. His voice had a deep, rough, rasping timber and as he talked his speech became rougher and the words seemed to be forced out by main effort. His movements were slow and seemed to be poorly coordinated when he walked. Memory, judgment and insight were poor. Rote memory andskills fearned from past experience were relatively unimpaired but there were significant deficits in his ability to learn new tasks and in motor speed. There was also evidence that he became depressed at times and was concerned about deterioration of bodily processes. He admitted that he drank excessively. The local radiologist stated that he had not been subject to any great amount of radiation during service and that no pathology should result from it. The diagnosis at discharge in September 1965 was chronic brain syndrome, associated with alcohol intoxication. In making these findings the Board noted: In addition to injury and alcoholism, a number of other causes for organic brain damage are recognized by the medical profession. Hence, the etiology of the veteran’s chronic brain syndromeis material only if it can be associated with some incident of service. It is shown that he received 4,495 roentgens of whole body exposure to Gammaradiation during the period from April 1956 to September 1956. This amount of exposure is below the level established by the National Committee on Radiation Exposure as permissible for adults who are exposed to radiation in the course of employment and, generally, would not be expected to cause any detectable changes in the skin or to have any adverse effects on body organs, Of added significance is the finding on radiation hazard studies that some body tissues are more sensitive to radiation injury than others. Where there is whole body exposure with all tissues subject to equal exposure, it would be anticipated that the most sensitive tissue would be the most susceptible to injury. Since there is no evidence in this case of damage to the bone marrow, the most sensitive tissue, it is unlikely that radiation is the cause of damage to the brain, one of the more resistant tissues. Another important factor in assessing the probable effect of radiation exposure is that the likelihood of injury is greater when the exposure is limited to an acute single dose than when the exposure occurs in small increments, over a period of time, as in this case. It must be concluded from the foregoing that there is no reasonable probability within the scope of present knowledge that veteran’s brain damage was caused by radiation exposure and, in the absence of any evidence to substantiate the veteran’s statements that symptoms ofhis brain disorder initially began during active service, it may not be held that the brain syndromehad its onset during active service. Findings of the BVA and Basis for Decision: In denying the appeal and concluding that the chronic brain syndrome was not incurred in or aggravated during active service the Board found: I. The veteran was exposed to Gammaradiation from April 1956 to September 1956, during which time he received an accumulative total dose of 4.495 roentgens as measured by film badge. 2. There is no record of radiation injury nor of any neuropsychiatric abnormality during active service or at separation therefrom. 3. A chronic brain syndrome was first medically established several years after service. . 4. The chronic brain syndrome is not related to or a residual of exposure to Gammaradiation during active service. 88 89