Akinetic mutism

Q: Akinetic mutism is due to injury to which part of the brain?

A) Temporal lobe
B) Parietal lobe
C) Frontal lobe
D) Occipital lobe
E) It is a psychiatric phenomenon


Answer: C

The objective of above question is to highlight a relatively less known phenomenon, akinetic mutism after a neurological insult. Due to injury to the frontal lobe, a patient does not initiate speech or movements. 

In akinetic mutism, a patient is not paralyzed but lack willingness. Alertness is present and patients' eyes may follow their observer or they may respond to audio clues. There are two kinds of akinetic mutism described. 1) Frontal or hyperpathic akinetic mutism as described above 2) Mesencephalic or somnolent akinetic mutism due to damage to the midbrain, where vertical gaze palsy and ophthalmoplegia can usually be demonstrated.

This is completely a distinct phenomenon. After an event of neural insult, a careful determination should be performed to differentiate between coma, persistent vegetative state, brain death, locked-in syndrome (coma vigilante) and dementia, as they all have different management and outcomes.

Treatment with intravenous magnesium sulfate has been said to be beneficial.



References:

Laureys S, Owen AM, Schiff ND. Brain function in coma, vegetative state, and related disorders. Lancet Neurol 2004; 3:537.

Nagaratnam, Nages; Kujan Nagaratnam; Kevin Ng; Patrick Diu (2004). "Akinetic mutism following stroke". Journal of Clinical Neuroscience. 11 (1): 25–30.Rozen, Todd (2012).

 "Rapid resolution of akinetic mutism in delayed post-hypoxic leukoencephalopathy with intravenous magnesium sulfate". Neurorehabilitation. 30 (4): 329–332