[A study of utilization and imitation behavior in cases with striatocapsular infarction]

Utilization behavior (UB) and imitation behavior (IB) were first described by Lhermitte (1983; 1986) for neurobehavioral disorders due to the frontal lobe damage. Recently, the similar symptoms were also observed in several reports of subcortical lesion cases without any lesion of the frontal lobe. We studied 16 consecutive patients with unilateral striatocapsular infarction (SCI), and found 7 patients (44%) presenting UB and/or IB. Characteristics of patients with UB and/or IB revealed the following factors: older age, higher frequency of right-sided lesion, absence of severe aphasia or apraxia, higher frequency of unilateral spatial neglect and/ or psychic change, and no evidence of significant large cerebral artery lesion on angiography. In most of SCI cases, whether IB and/or UB was present or not, the single-photon emission CT demonstrated decreased perfusion in the ipsilateral frontotemporal areas, and the result of neuropsychological assessment was compatible with frontal lobe dysfunction. UB and IB observed in our patients are not only considered to have resulted from secondary impairment of frontal lobe, but also regarded as one of the right hemispheric syndromes associated with such background factors as aging, neglect and general inattention.