Working memory processing for human voice perception in a patient with mild cognitive impairment: an FMRI study.

Functional neuroimaging techniques enable noninvasive measurements of cognitive functions in humans. We used functional neuroimaging to assess cognitive disturbance in a patient with mild cognitive impairment. The patient was a 58-year-old male with a mild memory disturbance, a mini-mental state examination (MMSE) score of 22 30, and a Clinical Dementia Rating Scale of 0.5. On the Wechsler Adult Intelligence Scale (WAIS-iii), intelligence quotient tests indicated total IQ=64, verbal IQ=71, and performance IQ=61. The patient showed mild cortical atrophy on structural magnetic resonance imaging (MRI) (T1-weighted image). To investigate cerebral function with regard to memory processing, we examined cerebral activation during an auditory working memory task (WMT) with voice materials from the Montreal Affective Voices. Functional magnetic resonance imaging (fMRI) was done while the patient carried out a WMT designed to test memory of emotional sounds. We analyzed cerebral response using a WMT>Rest contrast, which reflects the cerebral network of working memory in auditory emotional processing. The results were compared with the fMRI results of 14 control subjects performing the same tasks. In fMRI under WMT>Rest contrast, the cerebral network associated with emotional working memory activated in the control subjects consisted of the right dorsolateral prefrontal cortex, left precentral gyrus, left postcentral gyrus, bilateral superior temporal gyrus, bilateral middle temporal gyrus, right inferior parietal lobe, and right hippocampus [27, -15, -18] (Fig. 1 (a),1 (b)), whereas the right dorsolateral prefrontal cortex, right superior temporal gyrus, right middle temporal