Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Few studies have examined the neuropsychological and neurobehavioral profiles of patients with MJD. In this study, six individuals with MJD were given a battery of neuropsychological tests. Relative impairments on timed verbal attention tasks and verbal fluency (Stroop, Oral Symbol Digit Modalities, and Controlled Oral Word Association Test) were found. Other executive impairments also were seen on the Wisconsin Card Sorting Test, independent of motor dysfunction severity. Moderate- to severe levels of depressive symptoms were endorsed by four of the six patients, and caregivers observed increased apathy in the patients. Impaired executive and emotional functioning in MJD does not appear to be related to ataxia severity. These patients did not meet the criteria for dementia. General cognitive abilities, language, list learning, story recall, and untimed tasks of attention were within normal limits. Impaired executive abilities and emotional functioning in MJD patients is consistent with disruption of frontal-subcortical systems.

While neurobiological factors are known to play a role in human aggression, relatively few studies have examined neuropsychological contributions to propensity for violence. We previously demonstrated cognitive deficits among men who committed domestic violence (batterers) compared to non-violent controls. Batterers had deficits in verbal ability, learning and executive problem-solving ability. These findings led us to examine whether executive control problems involving impulsivity contribute to problems with behavioral control among batterers, and to further examine their deficits in verbal functioning. Batterers (n = 41) enrolled in a domestic violence program were compared to 20 non-violent men of similar age, education, and socioeconomic background on neuropsychological tests of executive functioning, including impulsivity. Questionnaires and structured clinical interviews were used to assess emotional distress, aggression and self-reported impulsivity. Batterers showed greater impulsivity compared to non-batterers on several neuropsychological measures. Yet, the severity of these deficits was relatively mild and not evident in all batterers. Consistent with our previous findings, significant verbal deficits were again observed among the batterers. These findings suggest that while impulsivity may be a factor associated with domestic violence, it probably is not the sole determinant of the strong relationship between cognitive functioning and batterer status that we previously observed. Both verbal expressive deficits and behavioral impulsivity appear to be relevant variables in predisposing men to domestic violence.

These findings support the initial psychometric properties and clinical utility of the LCI scores. We discuss strengths and limitations of this study, as well as potential clinical applications for the LCI questionnaire.