Two hours of CIMT may be more effective than conventional rehabilitation in improving motor function and use of the paretic arm in patients with chronic stroke.
Anosognosia for hemiplegia (AHP) is informative about the neurocognitive basis of motor awareness. However, it is frequently associated with concomitant symptoms, such as hemispatial neglect and disturbances in the sense of body ownership (DSO). Although double dissociations between these symptoms have been reported, there is ongoing debate about whether they are manifestations of independent abnormalities, or a single neurocognitive deficit.We aimed to investigate the specificity of lesions associated with AHP by surpassing four, existing methodological limitations: (a) recruit a relatively large sample of patients (total N = 70) in a multi-centre study; (b) identify lesions associated with AHP in grey and white matter using voxel-based methods; (c) take into account the duration of AHP and concomitant neglect symptoms; and (d) compare lesions against a control hemiplegic group , patients suffering from AHP and DSO, and a few, rare patients with selective DSO. Results indicated that acute AHP is associated with a wide network, mainly including: (1) the Rolandic operculum, (2) the insula and (3) the superior temporal gyri. Subcortically, damage mainly involved the basal ganglia and white matter, mostly the superior corona radiate, arcuate fasciculus and the ventral part of the superior longitudinal fasciculus. Persistent symptoms were linked with wider damage involving fronto-temporal cortex and long white matter tracts. A shift in the latero-medial direction (mainly involving the basal ganglia and surrounding white matter) emerged when DSO was taken accounted for. These results suggest that while bodily awareness is processed by areas widely distributed across the brain, intact subcortical structures and white matter tracts may be necessary to support basic feelings of owning and controlling contralateral body parts. An accurate and 'up-to-date' awareness of our motor abilities, however, may rely also on intact processing in cortical areas which presumably allow higher-order inferences about the current state of the body. Reviewer #1: The authors investigated the neuronal basis for anosognosia (AHP) and related disorders (body awareness and spatial neglect). The authors report a 70-strong study cohort, which they separate into different groups for their analysis and claim a different neuronal pattern for the acute and chronic stages of anosognosia. Whilst this study is well-written and strong neuropsychologically, the imaging analysis and in particular its interpretation lack substance. The anatomical regions described most the time do not match with the figures provided and therefore the conclusion of the current manuscript are not supported by the neuroimaging findings. The authors need to work on this aspect before publication should be considered.
Motor Versus Body
General comments1. The introduction is very well written and leads nicely to the research hypotheses. However, given the limited publications available on the neuronal basis of anosognosia the authors should make an effort to include a ...
The syndrome of Anosognosia for Hemiplegia (AHP) can provide unique insights into the neurocognitive processes of motor awareness. Yet, prior studies have only explored predominately discreet lesions. Using advanced structural neuroimaging methods in 174 patients with a right-hemisphere stroke, we were able to identify three neural systems that contribute to AHP, when disconnected or directly damaged: the (i) premotor loop (ii) limbic system, and (iii) ventral attentional network. Our results suggest that human motor awareness is contingent on the joint contribution of these three systems.
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