Perseveration as a sign of diffuse and focal brain damage. I.

Abstract

So far the clinical significance of perseveration has been con sidered only in relation to conditions giving rise to general disturbances of brain function. Indeed, it is observed so often in clouding of consciousness that little attention has been paid to it as a relatively isolated expression of focal brain damage. When found in patients with focal lesions the tendency has been to treat it as a residual or early fragment of general clouding of consciousness, the effect of which is to lessen the significance of any other intellectual defects that may be present at the time. Like the farmer, who would hesitate to waste time and energy on harvesting a field of grain which had become heavily con taminated by weed, the clinician sees little advantage in probing the mental state of such patients. Yet this attitude is not altogether justified, for in some patients recovering from a general disturbance of brain func tion, like anoxia or dehydration, perseveration is not seen, although the conditions necessary for its demonstration are there and it is searched for repeatedly. In the majority of these instances it is pronounced and affects all psychomotor activity, but in others there appears to be some element of selectivity at work, because it affects certain activities and not others. A third reason for studying perseveration out of its usual context, with clouding of consciousness, is that it has been described on occasion in patients with purely focal brain lesions.