Unraveling corticobasal syndrome and alien limb syndrome with structural brain imaging

Publication date: Available online 25 February 2019

Source: Cortex

Author(s): Franziska Albrecht, Karsten Mueller, Tommaso Ballarini, Leonie Lampe, Janine Diehl-Schmid, Klaus Fassbender, Klaus Fliessbach, Holger Jahn, Robert Jech, Jan Kassubek, Johannes Kornhuber, Bernhard Landwehrmeyer, Martin Lauer, Albert C. Ludolph, Epameinondas Lyros, Johannes Prudlo, Anja Schneider, Matthis Synofzik, Jens Wiltfang, Adrian Danek

Abstract

Alien limb phenomenon is a rare syndrome associated with a feeling of non-belonging and disowning toward one's limb. In contrast, anarchic limb phenomenon leads to involuntary but goal-directed movements. Alien/anarchic limb phenomena are frequent in corticobasal syndrome (CBS), an atypical parkinsonian syndrome characterized by rigidity, akinesia, dystonia, cortical sensory deficit, and apraxia.

The structure-function relationship of alien/anarchic limb was investigated in multi-centric structural MRI data. Whole-group and single-subject comparisons were made in 25 CBS and eight CBS-alien/anarchic limb patients vs. controls. Support vector machine was used to see if CBS with and without alien/anarchic limb could be distinguished by structural MRI patterns.

Whole-group comparison of CBS vs. controls revealed asymmetric frontotemporal atrophy. CBS with alien/anarchic limb syndrome vs. controls showed frontoparietal atrophy including the supplementary motor area contralateral to the side of the affected limb. Exploratory analysis identified frontotemporal regions encompassing the pre-/and postcentral gyrus as compromised in CBS with alien limb syndrome. Classification of CBS patients yielded accuracies of 79%. CBS-alien/anarchic limb syndrome was differentiated from CBS patients with an accuracy of 81%. Predictive differences were found in the cingulate gyrus spreading to frontomedian cortex, postcentral gyrus, and temporoparietoocipital regions.

We present the first MRI-based group analysis on CBS-alien/anarchic limb. Results pave the way for individual clinical syndrome prediction and allow understanding the underlying neurocognitive architecture.

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