Altered callosal function in cerebral microangiopathy

Abstract

Callosal dysfunction is known to be evident in a variety of neurodegenerative and inflammatory diseases of the central nervous system. Cerebral microangiopathy (CMA) may also affect callosal pathways by chronic demyelination. The aim of the present study was to investigate callosal function with respect to the extent of CMA. Callosal function was tested by a bimanual tapping task and by analysis of the ipsilateral silent period (iSP) and the transcallosal conduction time (TCT) using transcranial magnetic stimulation. Results were correlated to the extent of CMA measured by cranial magnetic resonance imaging (cMRI) in 44 patients with CMA compared to 10 control subjects. The extent of CMA was quantified by a cMRI score. Additionally, callosal atrophy was quantified by cMRI morphometry. Frequency of pathological iSP findings or disturbed bimanual tapping was significantly correlated to a higher CMA score. Moreover, the extent of CMA was significantly correlated to the degree of callosal atrophy. It is concluded that CMA considerably affects callosal pathways, possibly by chronic demyelination of callosal fibres. As the extent of CMA and atrophy of the corpus callosum is correlated to callosal dysfunction, analysis of the iSP can be used to assess the clinical impact of CMA detected by cMRI.

Callosal anatomical and effective connectivity between primary motor cortices predicts visually cued bimanual temporal coordination performance

“…Before the invention of modern structural and functional imaging, the role of the CC in bimanual coordination mainly had been studied in various pathological conditions. Patients with structural CC damage exhibited degradation of spatial and temporal components of bimanual coordination, pointing to the crucial importance of transcallosal information transfer (Caille et al 2005;Kennerley et al 2002;Preilowski 1972;Serrien et al 2001;Tuller and Kelso 1989;Caeyenberghs et al 2011;Bonzano et al 2014;Wittstock et al 2010). After a first-step partial section of the anterior CC in a patient with intractable epilepsy, deterioration of bimanual movement synchronization specifically for self-initiated movements was observed.…”

Preserved Transcallosal Inhibition to Transcranial Magnetic Stimulation in Nondemented Elderly Patients with Leukoaraiosis

“…Alternatively, it has been postulated that, in patients with extensive LA, atrophy and reduced diffusion anisotropy of the CC may indicate diffuse hemispheric deep white matter tract damage, which may explain global cognitive impairment and development of vascular dementia [37]. Finally, cerebral microangiopathy may also affect callosal pathways by chronic demyelination [38]. …”

Role of Magnetic Resonance Imaging in Morphometric Alterations of Corpus Callosum in Stroke Patients

“…Similarly, other authors like Wu et al have noted similar results in their study [ 11 ]. Wittstock et al also performed a similar study using T2-weighted MRI and found hyperdense areas in the brain white matter with thinner dimensions [ 15 ]. Literature reveals that these changes are chronic in nature and may be due to the demyelination of fibers of the corpus callosum [ 15 ].…”