Akinetic Mutism

Akinetic Mutism

1. Akinetic mutism Ade Wijaya, MD March 2020

2. Introduction Initial description in 1941 A rare neurological disorder of impaired initiation and motivation for behavior Patient maintain an intact level of consciousness, attention, language, and sensorimotor capacity, but present with a simultaneous decrease in goal-directed behavior, and emotion Frontal-subcortical circuits dysfunction B.L. Miller, J.L. Cummings The Human Frontal Lobes: Functions and Disorders ( 3th ed.), The Guilford Press, New York (2018) F.M. Skultety Clinical and experimental aspects of akinetic mutism Report of a case. Arch Neurol, 19 (1968), pp. 1-14 Aspen Workgroup Recommendations for use of uniform nomenclature pertinent to patients with severe alterations in consciousness. American Congress of Rehabilitation Medicine Arch . Phys. Med. Rehabil., 76 (1995), pp. 205-209

3. Pathophysiology Connecting between the decision-making process of the frontal lobe and the ‘emotional’ world of the limbic system The ACC is responsible for learning and selecting high-level behavioral plans that provide the meaning behind and motivation for actions, and is thought to be essential in making a transition from early premotor processes to actual behavior Voluntary initiation of speech and vocalization through connections with brainstem periaqueductal grey that in turn connects with brainstem nuclei that innervate the muscles of articulation and phonation A nterior cingulate cortex (ACC)   C.B. Holroyd, N. Yeung Motivation of extended behaviors by anterior cingulate cortex Trends Cogn. Sci. (Regul. Ed.), 16 (2012), pp. 122-128 U. Jurgens The neural control of vocalization in mammals: a review J . Voice, 23 (2009), pp. 1-10 N. Medford, H.D. Critchley Conjoint activity of anterior insular and anterior cingulate cortex: awareness and response Brain Struct. Funct., 214 (2010), pp. 535-549 A. Shenhav, M.M. Botvinick, J.D. Cohen The expected value of control: an integrative theory of anterior cingulate cortex function Neuron , 79 (2013), pp. 217-240

4. Pathophysiology Striatum, The Pallidal Complex, Thalamus Arnts H, van Erp WS, Lavrijsen JC, van Gaal S, Groenewegen HJ, van den Munckhof P. On the pathophysiology and treatment of akinetic mutism. Neuroscience & Biobehavioral Reviews. 2020 Feb 7.

5. Pathophysiology The dopaminergic neurons, located in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) in the midbrain play an important role in motivational neurocircuitry and modulate a broad range of behavioral and motor control processes Damage to the dopaminergic neurons at their site of origin is a well-known cause of akinetic mutism The role of mesolimbic and nigrostriatal dopaminergic pathways Arnts H, van Erp WS, Lavrijsen JC, van Gaal S, Groenewegen HJ, van den Munckhof P. On the pathophysiology and treatment of akinetic mutism. Neuroscience & Biobehavioral Reviews. 2020 Feb 7.

6. Treatment Treat the underlying cause Dopamine agonist therapy M ethylphenidate and atomoxetine Zolpidem

7. Summary A rare severe neurological disorder L ack the motivating vector for the expression of spontaneous motor behavior and speech It results in near-complete dependence on others for the most basic activities of daily life, invariably leading to nursing home admission Frontal-subcortical circuits dysfunction

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