Motor neglect and future directions for research.

摘要: Here we present an opinion on “motor neglect,” one of the several scotomas in neglect research (Kerkhoff and Schenk, 2012). We describe what it is, outline its anatomical substrate, frequency a stroke population. evidence to suggest that motor reflects impaired ability generate movements discuss possible rehabilitation technique which may target this particular deficiency. feel is timely “opinion.” Motor occur absence visuospatial (Laplane Degos, 1983; Punt et al., 2005) can have severe detrimental effect outcomes (Siekierka-Kleiser 2006). “Motor term originally coined by Laplane Degos (1983), refers underutilization affected limb compared healthy following brain damage despite normal muscle strength, reflexes, sensation. It be distinguished from “directional hypokinesia” (originally described Heilman 1985) referring slowness initiation contralesional movements, reduced spatial exploration toward side, insufficient amplitude movements. Patients with typically underuse side (even where involves inconvenience); little or no involvement bimanual tasks (e.g., clapping, opening bottle); when automatically gesturing; however, they relatively movement encouraged specifically use Riddoch, 2006; Garbarini 2012a,b). Unlike patients hemiplegia, paresis, increase tone, pyramidal signs, alterations sensation (von Giesen 1994). There information how these are able manage their activities everyday living. (1983) increased determination part patient results eventually being performed (they right hemisphere lesions using verbal strategies, while left become “left-handed”). There differential reports as neglect. Siekierka-Kleiser al. (2006), report incidence 33% acute population 74% sample having lesions, Buxbaum (2004) 12% 8% chronic (all study had lesions). According show poor recovery over first 7 days post-stroke relative without neglect; although sub-group (26.3%) recovered well, two lesions. von (1994), positron emission tomography (PET) four neglect, demonstrated primary areas underlying output system (the sensorimotor cortex, basal ganglia, cerebellum) were unimpaired, there was glucose uptake premotor, prefrontal, parietal, cingulate cortex areas, well thalamus. This substantiates clinical manifestation von hypothesized intact cortical deprived sensory voluntary drive needed for execution (see also 1983). Recent implicating parietal regions generation comes Desmurget (2009). They contrasted effects direct stimulation premotor regions. Stimulation inferior (IPL) produced desire move any overt EMG activity recorded concerned muscles. If intensity increased, reported occurred; again, actual observed. et al. argue “wanting act feeling,” resulting IPL stimulation, indicative intentions generated before (Desmurget Sirigu, 2009, 2012; 2009). Sirigu shown lobe (involving angular gyrus particular) result deficits subjective experience wanting task free execute at time own choosing. Thus, behaviorally, control participants anticipatory period prior movement, very close initiated. The inability actions illustrated recent study. (2012a,b) performance (and lack initiate action but acts) anosognosia (who reverse deficit, ability). While blindfolded, draw circles lines, either performing unimanual drawing hand drew unilateral lines) lines simultaneously, circles). showed coupling, found subjects not such coupling preserved anosognosic hemiplegic patients. particularly striking finding given unable limb, neglect. As yet (as far know) been studies addressing Exciting new techniques repetitive TMS tDCS (used enhance lesioned suppressing over-activity observed unaffected hemisphere) used general particular. facilitate ipsilesional performance, clear benefit planning. Increasing improve – (2009) increasing generation. Rehme Grefkes (2013) argued best predictor good (from phase phase) between (supplementary area, ventral M1). Such critical Recent noradrenergic (NA) tool job. (2010) crossover design stimulated selective noradrenaline reuptake inhibitor reboxetine (RBX) placebo. The goal directed joy-stick. Drug-related changes blood oxygen level dependent interregional connectivity assessed functional magnetic resonance imaging (fMRI) dynamic causal modeling (DCM). speed RBX (with corresponding regional activation), complex network affecting both neural processing within across hemispheres. Within hemisphere, enhanced known involved attention Corbetta Shulman, 2002). In addition, V1, IPS, FEF/dPMC hemispheric independent difficulty. activation engagement transformation processes facilitating integration visual into planned programs. Subsequently, Wang (2011) studied NA behavioral levels fMRI sub DCM applied data key assess system. reduction “hyperactivity” physiological subjects, especially PMC SMA, TPJ prefrontal cortex. Together help modulate pathologically altered architecture patients, improving function. Future significance showing visuomotor intention disconnectivity greatest (Rehme 2011). As course spontaneous neurological impairment shows natural logistic curve up 12–14 weeks post-stroke, after severity becomes invariant (Kwakkel 2004; Nijboer 2012), most beneficial time-window facilitation recovery.