Role of corpus callosum integrity in arm function differs based on motor severity after stroke

Abstract

While the corpus callosum (CC) is important to normal sensorimotor function, its role in motor function after stroke is less well understood. This study examined the relationship between structural integrity of the motor and sensory sections of the CC, as reflected by fractional anisotropy (FA), and motor function in individuals with a range of motor impairment level due to stroke. Fifty-five individuals with chronic stroke (Fugl-Meyer motor score range 14 to 61) and 18 healthy controls underwent diffusion tensor imaging and a set of motor behavior tests. Mean FA from the motor and sensory regions of the CC and from corticospinal tract (CST) were extracted and relationships with behavioral measures evaluated. Across all participants, FA in both CC regions was significantly decreased after stroke (p < 0.001) and showed a significant, positive correlation with level of motor function. However, these relationships varied based on degree of motor impairment: in individuals with relatively less motor impairment (Fugl-Meyer motor score > 39), motor status correlated with FA in the CC but not the CST, while in individuals with relatively greater motor impairment (Fugl-Meyer motor score ≤ 39), motor status correlated with FA in the CST but not the CC. The role interhemispheric motor connections play in motor function after stroke may differ based on level of motor impairment. These findings emphasize the heterogeneity of stroke, and suggest that biomarkers and treatment approaches targeting separate subgroups may be warranted.

PREP2: A biomarker‐based algorithm for predicting upper limb function after stroke

“…Further work could usefully explore other neuroimaging biomarkers that might provide important prognostic information for MEP− patients. These may involve measures of alternative descending motor pathways,25, 26, 27, 28 and of the wider ipsilesional and contralesional sensorimotor networks, including the corpus callosum 29, 30, 31, 32, 33. However, more sophisticated measures may also require expertise not readily available in most clinical settings.…”

Multimodal DTI-TMS assessment of the motor system in patients with chronic ischemic stroke

“…Indeed, one study suggested that FA in the CC motor region, explains the motor deficit scores better than FA in the CST in a subgroup of patients with minor motor impairment. 33 While in other studies, relationships between CC integrity and recovery were shown for the prefrontal CC region 31,40 , and in one of them 31 , such association existed only in a subgroup of the most severely affected patients. We defined the CC ROI based on voxelbased comparison of the "good" and "bad outcome" groups.…”

“…7 There is currently no consensus which CC areas are the most discriminative for stroke patients with motor deficit. [31][32][33] Thus, we decided to perform voxel-based comparison of FA maps between the best (Group1) and the worst recovered patients (Group3). Normalized FA maps of Group3 and Group1 were compared using two-sample t-test with the CC masks using SPM8.…”

Protective Efffects of Melatonin in Corpus Callosum Astrocytes during Ischemia in Transgenic Mice

“…Targeting astrocytes in the penumbra region, area around the ischemic core, is of great potential as a therapeutic intervention for stroke patients and may limit infarct size and further damage. Corpus callosum involvement in the infarcted area of stroke has been reported in several clinical studies [14,15] . Th e aim of the current study is to examine the eff ect of melatonin on adult corpus callosum astrocytes during an oxygen glucose deprivation (OGD) model of ischemia in transgenic mice, focusing on the role of MT1 and MT2 receptors.…”