Background. Neuropsychological consequences of cerebral stroke include among others various self-control defi cits that not only impair the patients' emotional and personality functioning, but also disorganize the course of their cognitive and motor activities. The aim of the study was to assess the frequency, clinical characteristics and neuroimaging correlates of inhibitory control impairment in selected cognitive and motor functions following brain stroke.
Method. Two groups of participants were studied. The clinical group consisted of 65 patients after unilateral ischemic cerebral stroke. They were included on the grounds of their medical history and CT and/or MRI scans. The time from onset was less than a month. The control group consisted of 25 healthy volunteers. The participants' inhibitory control level was assessed using two popular tasks, i.e. an experimental version of the Stroop Color-Word Test (SCWT) and a standardized go/no-go task (GNG) that required the subjects to perform confl icting motor responses.
Results. Inhibitory control dysfunction was found in 54 patients (i.e. 83% of the clinical group), who failed to complete at least one of the two tasks. One-way repeated-measures ANOVA with post hoc Tukey's test indicated that patients with a selective damage site in the posterior part of the brain performed the tasks within the normal range, i.e. at the same level as did the healthy controls. Moreover, their performance was signifi cantly superior to that of patients with damage either to the frontal lobe (FRL) or to subcortical structures (SUB). It was only the patients with FRL or SUB damages whose performance on the GNG task was diagnostically lower than their SCWT scores.
Conclusions. Inhibitory control dysfunction affecting the performance of automated verbal and motor sequences was a very frequent symptom of cerebral stroke. There were individual differences in disinhibition specificity and severity. The most severe symptoms were noted in patients with frontal lobe damage or in those with damage to some specific subcortical structures such as the striatum or thalamus and their cortical connections.