[Neuropsychologic outcome after bilateral pallidotomy in patients with Parkinson disease]

Although significant improvement of motor function following bilateral pallidotomy for the treatment of Parkinson's disease has been proved, the cognitive sequelae have not been clearly defined. There are recurrent loops interconnecting specific areas of the frontal cortex and the basal ganglia, suggesting the continuity or complementary functioning between these areas.

Pre- and postoperative cognitive function was evaluated in 19 Parkinsonian patients who underwent bilateral pallidotomy in order to clarify its effects on cognitive function. All patients were evaluated one day before the procedure and 12+ months after surgery using neuropsychological tests (Raven Progressive Matrices and Bergen Facial Recognition Test). Proper performance in these tests requires reasoning, abstraction and spatial memory, involving strongly the frontal functions. These functions could be described in terms of the "working memory" concept. Hand Mental Rotation Test was used as comparing task not involving frontal functions. Scores were analyzed by Student's t-test.

Modest improvement was observed in these cognitive functions as assessed by Raven Progressive Matrices (p < 0.0688) and a significant change in the complex parts of Bergen Facial Recognition Test (p < 0.0547; p < 0.0468) was also noticed, but no change was registered in mental rotation tasks.

Present data revealed that bilateral pallidotomy is associated with modest and long-lasting improvement in tasks involving the "working memory".