Long-term outcomes in motor and cognitive impairment with acute encephalopathy

Background: Acute encephalopathy causes various sequelae, including motor disabilities and intellectual delays. Previous studies reported that cognitive impairments can also occur after acute encephalitis. Although the incidence of acute encephalopathy is high in Japan, there have been few reports on its sequelae.

Objective: To characterize the neurological outcomes of pediatric patients who sought motor rehabilitation for motor dysfunction after acute encephalopathy.

Method: Subjects were 26 children who were healthy before suffering from motor dysfunction following acute encephalopathy and were referred to our pediatric rehabilitation institute during a 9-year period (August 2007-April 2017). We examined subjects' neurological status and followed sequelae for at least 8 months.

Results: Of 26 individuals, 21 became ambulatory after several months or years during the observation period. Patients who could sit without support within 5 months after the onset of acute encephalopathy were able to walk within several months or years. Patients showing high intensity on T2-weighted sequences or "bright tree appearance" in the frontal region took an average of 7 months to develop walking, which was longer than other patients. Among ambulatory subjects, 16(76%) exhibited mild to moderate intellectual delay with a developmental quotient (DQ) under 70, and 20 (95%) exhibited cognitive impairment. There was a significant correlation between DQ scores and motor disability (p = 0.013, r = -0.481).

Conclusions: Although 80% of patients who had motor dysfunction caused by acute encephalopathy and visited out motor rehabilitation outpatient clinic were eventually able to walk, the time taken to develop walking ability depended on which region exhibited magnetic resonance imaging abnormalities. DQ scores and motor disability were significantly correlated.