White matter tract involvement in anarchic hand syndrome following stroke: Diffusion tensor imaging study

Area of Science:

• Neurology
• Neuroimaging
• Neuroanatomy

Background:

• Anarchic Hand Syndrome (AHS) is a rare neurological disorder causing involuntary, purposeful hand movements.
• The precise white matter pathways underlying AHS remain incompletely understood, though damage to the corpus callosum (CC) and other tracts is implicated.

Purpose of the Study:

• To identify specific white matter tracts associated with the development of Anarchic Hand Syndrome (AHS).
• To investigate the role of corpus callosum (CC) and intra-hemispheric tract integrity in AHS using diffusion tensor imaging (DTI).

Main Methods:

• Utilized diffusion tensor imaging (DTI) to reconstruct 42 white matter tracts.
• Employed the TRActs Constrained by UnderLying Anatomy (TRACULA) technique to extract fractional anisotropy (FA) and volume values.
• Compared DTI metrics between three female AHS patients with anterior cerebral arterial (ACA) infarctions, 20 age-matched controls, and six non-AHS patients with ACA infarctions.

Main Results:

• The AHS group exhibited significantly lower FA values in the CC body (parietal and temporal sections), right arcuate fasciculus (AF), corticospinal tract, extreme capsule, inferior longitudinal fasciculus (ILF), and superior longitudinal fasciculus compared to controls.
• No significant differences in these tracts were observed between the non-AHS and control groups.
• A reduced volume in the genu of the CC was noted in the AHS group, but not in other analyzed tracts.

Conclusions:

• Extensive lesions in the posterior parietal and temporal sections of the CC body, along with damage to intra-hemispheric tracts like the AF and ILF, are associated with Anarchic Hand Syndrome (AHS).
• These findings highlight the importance of considering complex network disruptions involving multiple white matter tracts beyond the CC for a comprehensive understanding of AHS pathophysiology.