[Improvement of cognition after trepanation for the chronic subdural hematoma]

The cognitive functions were examined in the pre- and post-operative stages about the 16 cases of the chronic subdural hematoma. The evaluation was performed with MMS (mini-mental state) test. Although the average of the total score was 16.6 in the preoperative stage, it increased to 22.7 in the postoperative stage. Orientation of time and place, recall and the ability of writing a sentence, which were impaired prominently in the preoperative stage, improved significantly in the postoperative stage. The improvement was poorer in the patients with gait instability and in those older than 80 years. Trepanation surgery seems to be efficient for the improvement of cognition.