Utilisation Behaviour Consequent to Bilateral SMA Softening

• Published in: Cortex Vol. 38; no. 3; pp. 289 - 308
• Main Authors: Boccardi, Edoardo, Sala, Sergio Della, Motto, Cristina, Spinnler, Hans
• Format: Journal Article
• Language: English
• Published: Italy Elsevier Srl 01-06-2002
• Subjects: anarchic hand; anterior cerebral artery; azygous; Brain Mapping; Cerebral Angiography; Compulsive Behavior - diagnosis; Compulsive Behavior - physiopathology; Dominance, Cerebral - physiology; Frontal Lobe - physiopathology; frontal lobes; Functional Laterality - physiology; Hand Strength - physiology; Humans; Infarction, Anterior Cerebral Artery - diagnosis; Infarction, Anterior Cerebral Artery - physiopathology; Intracranial Arteriovenous Malformations - diagnosis; Intracranial Arteriovenous Malformations - physiopathology; Magnetic Resonance Imaging; Male; Middle Aged; Motor Cortex - blood supply; Motor Cortex - physiopathology; Nerve Net - physiopathology; Neuropsychological Tests; Psychomotor Disorders - diagnosis; Psychomotor Disorders - physiopathology; Stereotyped Behavior - physiology; supplementary motor area; utilisation behaviour; utilisation behaviour; supplementary motor area; azygous; anarchic hand; anterior cerebral artery; frontal lobes
• ISSN: 0010-9452; 1973-8102
• DOI: 10.1016/S0010-9452(08)70661-0

The case of patient CU, who presented with severe utilisation behaviour, eventually unaccompanied by psychometric signs of frontal involvement, is reported. He suffered from a bilateral stroke within the territory of the anterior cerebral artery. His arterial system was characterised by a unique variant, whereby the right anterior cerebral artery was missing and three trunks originated from the left anterior cerebral artery, each bifurcating into right and left branches. An occlusion of the middle trunk immediately before its partition gave rise to a symmetrical bilateral parasagittal lesion that damaged the supplementary motor areas (medial part of Brodmann's area 6), sparing the lateral regions including the premotor cortices, the corpus callosum and the gyri cinguli. The hypothesis is put forward that utilisation behaviour should be conceived as a double anarchic hand, and its interpretation should rest on the damaged balance between the premotor cortices, responsive to environmental triggers, and the supplementary motor areas, which modulate actions and inhibit them. The imbalance due to the lesion would result in the patients being left at the mercy of environmental stimuli, unable to inhibit inappropriate actions. This intra-frontal hypothesis accounts for the data presented and those from the literature better than the previously held fronto-parietal equipoise.