Prolonged rigid mutism following involvement of the frontal subcortical and forebrain dopaminergic systems due to right fronto-parietal haemorrhage
Nages Nagaratnam, Ilesh Patel
CaseRepClinPractRev 2005; 6:177-181
Background: Akinetic mutism is a state of apparent alertness with normal eye movements with no volitional motor function or speech output. It may be due to a number of causes and often follows a stroke. It usually lasts from days to weeks but less commonly for months to years. Case Report: A 72-year-old right-handed man with rigid mutism due to a right fronto-parietal haematoma is described. Serial CT scans of the brain revealed a large haemorrhage with surrounding infarction in the right fronto-parietal region at the level of the centrum semi-ovale and the right periventricular white matter. There was midline shift with compression of the adjacent left cerebral hemisphere involving the motor and supplementary motor areas as well as the prefrontal regions in both hemispheres. There was total weakness of the left side. On the right, a mixed picture of pyramidal and extrapyramidal signs was found, with increased tone of the cogwheel type, ankle clonus and equivocal plantar response and frontal release signs,. There was no verbal output for 20 weeks with marked akinesia. He had no buccofacial apraxia but had overall reduction in prosody and gesturing. At the end of eighteen months he remained mute.Conclusions: This specific type of prolonged rigid akinetic mutism could be explained by damage to the frontal lobe and or interruption of the complex frontal subcortical circuits and involvement of the forebrain dopaminergic and basal ganglia systems.
Keywords: akinetic mutism, Stroke, cerebral haemorrhage, supplementary motor area