Neuropsychological and Brain Volume Differences in Patients with Left- and Right-Beginning Corticobasal Syndrome

Abstract

BackgroundCorticobasal Syndrome (CBS) is a rare neurodegenerative syndrome characterized by unilaterally beginning frontoparietal and basal ganglia atrophy. The study aimed to prove the hypothesis that there are differences in hemispheric susceptibility to disease-related changes.MethodsTwo groups of CBS patients with symptoms starting either on the left or right body side were investigated. Groups consisted of four patients each and were matched for sex, age and disease duration. Patient groups and a group of eight healthy age-matched controls were analyzed using deformation field morphometry and neuropsychological testing. To further characterize individual disease progression regarding brain atrophy and neuropsychological performance, two female, disease duration-matched patients differing in initially impaired body side were followed over six months.ResultsA distinct pattern of neural atrophy and neuropsychological performance was revealed for both CBS: Patients with initial right-sided impairment (r-CBS) revealed atrophy predominantly in frontoparietal areas and showed, except from apraxia, no other cognitive deficits. In contrast, patients with impairment of the left body side (l-CBS) revealed more widespread atrophy, extending from frontoparietal to orbitofrontal and temporal regions; and apraxia, perceptional and memory deficits could be found. A similar pattern of morphological and neuropsychological differences was found for the individual disease progression in l-CBS and r-CBS single cases.ConclusionsFor similar durations of disease, volumetric grey matter loss related to CBS pathology appeared earlier and progressed faster in l-CBS than in r-CBS. Cognitive impairment in r-CBS was characterized by apraxia, and additional memory and perceptional deficits for l-CBS.

Primary motor cortex LTP/LTD-like plasticity in probable corticobasal syndrome

“…supplementary motor area, superior parietal cortex, and posterior cingulate cortex (Borroni et al 2008;Boxer et al 2006;Huey et al 2009;Jütten et al 2014;Lee et al 2011;Whitwell et al 2010), we suggest that the abnormally increased responses to TBS delivered over the M1 contralateral to the more affected limb might reflect a cortico-cortical disconnection syndrome due to a broader and asymmetric cortical degeneration process occurring in a specific subgroup of patients with probable CBS. The unexpected pattern of abnormally increased responses to TBS observed in the four patients (Table 1) resembles that previously reported in PSP (Conte et al 2012).…”

“…The heterogeneous TBS features observed in our cohort of patients with probable CBS undergoing Experiment 2 might reflect the lateralization (right or left) of upper limb motor symptom. In CBS, a recent MRI study of Jütten et al (2014) demonstrated that compared with patients with right-side disease onset, those with left-side disease onset manifested earlier and had a more prominent cortical gray matter loss, leading to more severe motor and nonmotor symptoms. The observation of Jütten et al (2014) is in line with a previous report in a cohort of right-handed patients with PD demonstrating that patients who manifested left-side motor symptom onset developed earlier motor disability (Marras et al 2011).…”

“…In CBS, a recent MRI study of Jütten et al (2014) demonstrated that compared with patients with right-side disease onset, those with left-side disease onset manifested earlier and had a more prominent cortical gray matter loss, leading to more severe motor and nonmotor symptoms. The observation of Jütten et al (2014) is in line with a previous report in a cohort of right-handed patients with PD demonstrating that patients who manifested left-side motor symptom onset developed earlier motor disability (Marras et al 2011). In our cohort of right-handed patients with probable CBS, we found that the lateralization (right or left) of upper limb motor symptom onset is homogeneously present in the three subgroups of CBS patients who manifested different neurophysiological patterns of response to TBS in Experiment 2 (see Table 1).…”

“…We cannot fully exclude the possibility, however, that at least some part of the neurophysiological heterogeneity observed in our study might also reflect neuropathological conditions other than CBD. A final comment is that the high M1 LTP/LTD-like plasticity asymmetry index in some patients with probable CBS manifesting abnormally increased responses to TBS might reflect specific asymmetric pathophysiological mechanisms in the two hemispheres in line with neuropathological and neuroimaging evidence of asymmetric neurodegenerative processes in widespread cortical regions in addition to M1 and basal ganglia pathology (Borroni et al 2008;Boxer et al 2006;Huey et al 2009;Jütten et al 2014;Katayama et al 2010;Lee et al 2011).…”

Corticobasal syndrome: neuroimaging and neurophysiological advances

“… and Jütten et al . reported an asymmetric fronto‐parietal atrophy contralateral to the apraxic limb suggesting unbalanced involvement of cortical atrophy in the pathophysiology of higher cortical symptoms. When Upadhyay et al .…”