[Paramedian thalamic and midbrain infarcts associated with palilalia]

We report a case with paramedian thalamic and midbrain infarcts associated with palilalia. A 62-year-old man fell into a comatose state, and was admitted to an emergency hospital. Two days later, his consciousness level began to improve. Neurological examination revealed bilateral cerebellar ataxia, oculomotor nerve palsy, lack of spontaneity, and amnesia. Deep tendon reflexes were normal on all extremities, and no muscular weakness was observed. Babinski sign was noted on the right side. Muscle tone was decreased. No sensory disturbance was found. Two months later, he began to show compulsive repetition of syllables, words, or phrases, and was transferred to our hospital. He involuntarily repeated one syllable or a word five to ten times in spontaneous speech, repetition of phrases being not so frequent as that of syllables or words. This speech abnormality was considered as palilalia, which Souques first reported in 1908. The palilalia of this patient was rarely noted when he repeated words spoken to him by the examiner. As he spoke, the rate of speech gradually increased, the loudness reduced, and finally he began to whisper (palilalie aphone). The palilalia continued for four months. MRI showed infarcts in the medial thalami, subthalamic and midbrain on both sides. Auditory brainstem response showed delayed latency of bilateral V waves, and EEG revealed bilateral theta waves. In this patient no lesion other than thalamus, subthalamus and midbrain was detected by MRI. It is suggested that bilateral lesion of the thalami and their projection areas caused palilalia in this patient.