Clinical aspects of La Crosse encephalitis: neurological and psychological sequelae.

Only rarely will a child continue to have focal neurologic findings, such as paresis, for as long as 8 years after LAC encephalitis. Most of the other focal neurologic findings, such as Babinski reflexes, pathologic reflexes, aphasias, choreas, dysarthrias and ataxias, resolve completely. Abnormal electroencephalographic findings during the acute period were note in 86-100% of the cases. On 1-8 year follow-up, EEG abnormalities were noted in approximately 33% of the subjects tested. Seizures are present at high frequency during acute illness and recurrent seizures may occur in 6-13% of the cases 1-8 years after infection. The cognitive and intellectual functioning of children following LAC encephalitis is not significantly different from that of the normal population. As a group, LAC encephalitis victims also function in the normal range in terms of their academic performances. There are individuals, however, who will have suffered permanent destructive lesions resulting in lowered IQ and lowered school performance. Behavioral abnormalities are difficult to measure and when present, difficult to ascribe to a definitive cause.