Akinetic mutism following stroke.

This is an appraisal of the varied clinical presentation and the neural substrate for akinetic mutism following stroke. The diagnosis is important as akinetic mutism is often misdiagnosed as depression, delirium and locked-in-syndrome. This is a descriptive study of eight selected patients with akinetic mutism following infarction/haemorrhage in different regions of the brain with characteristic syndromes. They involved the critical areas namely, the frontal (cingulate gyrus, supplementary motor area and dorso-lateral border zone), basal ganglia (caudate, putamen), the mesencephalon and thalamus. The disorders of speech and communication took different forms. The speech disorder included verbal inertia, hypophonia, perseveration, softened and at times slurred. The linguistic disturbances were fluent, non-fluent, anomia and transcortical (motor, mixed) aphasias. The findings were related to what is known about the neuroanatomic location of the lesions and the role of the frontal-subcortical circuitry in relation to behaviour. Akinetic mutism could be explained by damage to the frontal lobe and or interruption of the complex frontal subcortical circuits.