The main interest in these cases centres in the defects produced in the area of the visual field. I am extremely indebted to my colleague, Mr. J. H. Fisher, who has kindly determined this for me in three of the following cases. It will be noted that in two instances the injury was to the left occipital lobe. In these the resulting hemianopsia was of the pure lateral homonymous character, and in both the visual symptoms were accompanied by a certain degree of amnesic aphasia (65 and 68).
In 65 the injury was definitely unilateral, and at the time of the operation I decided that at least an inch and a half of the posterior extremity of the left occipital lobe was totally destroyed.
In 68 the lesion was probably confined to the left lobe, but it is impossible to exclude slight injury to the right lobe also. In this instance amnesic aphasia was a far more marked symptom than in 65, and the position of the lesion suggested damage both to the visual and auditory word centres.
Cases 66 and 67 are instances of damage to both occipital lobes. In 66, although the wound was a glancing one, and did not perforate, it was so near the median line, and accompanied by such severe damage to the bone, that a symmetrical lesion of the cuneate and precuneate lobules of both right and left sides is to be inferred. In 67 the great longitudinal fissure was traversed by the bullet obliquely. It is of great interest to observe that in each of these cases the lesion of the visual field was a horizontal one and affected the lower half in place of assuming a lateral distribution.
In all four cases the primary effect of the occipital injury was the same—viz. absolute blindness—while the return of vision in each was of the nature of the dawning of light. I regret that I am unable to furnish any detail as to increase of the field of vision in the progress of the cases, but circumstances rendered continuous observation of the patients impossible.
In each case deafness was apparently the direct result of concussion of the ear on the side corresponding to the wound. Deafness of the opposite ear was never noted.
In case 67 some general blunting of sensation was noted in the paralysed upper extremity, and in this patient, no doubt, injury to the inferior parietal lobule accompanied the occipital lesion.
(65) Injury to left occipital lobe.—Wounded at Belmont. A single transverse wound, 2 inches in length, extended across the occipital bone, 2 inches above the level of the external protuberance. When seen on the third day the wound was gaping and pulped cerebral matter was found in it. The patient was very drowsy, lying with closed eyes, and complaining of great coronal and frontal headache. He could distinguish light and darkness, but not persons. Total blindness immediately followed the injury, persisting some three days, and the patient spoke of return of sight as of the appearance of dawn. The pupils were equal, moderately dilated and acted to light, which was unpleasant to him. He was somewhat irritable and silent, but apparently rational. Temperature 99°. Pulse 56 full. Tongue clean. No sickness, no difficulty in micturition.
Fifty-six hours after the injury the wound was opened up and cleaned, and an oval fractured opening about 3/4 by 1/2 inch was exposed 3/4 inch to the left, and 2 inches above the occipital protuberance. The margins of the opening showed several small fragments of lead attached to the bone. A 3/4-inch trephine was applied at the left extremity of the opening, and it was found that about a square inch of the internal table was comminuted and driven into the brain, together with several small fragments of lead. On introducing the finger, about 1½ square inches of the occipital lobe were found to be pulped, and the finger could be swept across the tentorium. There was no sinus hæmorrhage (nor did the history suggest that hæmorrhage had ever been severe). The cavity was carefully sponged out, and the wound closed with a drainage aperture. Little change followed in the patient's condition, and on the sixth day he was sent to the Base hospital.
Three weeks later the wound was firmly healed. The patient still complained of frontal headache, and wore a shade, as the light hurt his eyes and made them water freely. The pupils acted, but were wide; objects could be distinguished, and also persons. Otherwise, the man's condition was good: he began to get up, and at the end of six weeks returned to England.