Impaired novelty processing in apathy after subcortical stroke.
OBJECTIVE
Apathy is associated with decreased novelty-seeking behaviors and is a prevailing behavioral symptom after stroke affecting cortical and subcortical regions. We studied the relationship between apathetic state after subcortical stroke and neural orienting response to novel events using an event-related evoked potential (ERP) technique.


METHODS
Twenty-nine patients with subcortical ischemic stroke were grouped according to whether they showed apathy or not. We analyzed apathy state scaled by the modified Starkstein apathy score and auditory P3 ERP components evoked by task-relevant target stimuli (target P3) and task-irrelevant novel stimuli (novelty P3).


RESULTS
The apathetic group showed a significantly lower score of verbal fluency test and global cognitive function test compared with the nonapathetic group. The novelty P3 latency was significantly prolonged, and its amplitude was reduced over the frontal site in the apathy group. The apathy scale was correlated with the novelty P3 latency and amplitude at the frontal site. The target P3 measures were related to global cognitive function.


CONCLUSIONS
The present study suggests that apathy after subcortical stroke is associated with impaired neural processing of novel events within the frontal-subcortical system and that the novelty P3 is a useful physiological measure for assessing apathy after stroke.
Yamagata
Shingo
S
Department of Neurology, Hematology, and Rheumatology, Shimane University School of Medicine, Izumo, Japan.
Yamaguchi
Shuhei
S
Kobayashi
Shotai
S
D000339:Affect; D000368:Aged; D002544:Cerebral Infarction / Q000503:physiopathology / Q000523:psychology*; D004569:Electroencephalography; D005071:Evoked Potentials; D005106:Exploratory Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests