Sequential activation brain mapping after subcortical stroke: changes in hemispheric balance and recovery

Abstract

We prospectively studied 5 patients while they were recovering from left-sided subcortical stroke affecting the cortico-spinal tract, and examined them twice with H(2)(15)O-PET over several months while performing an identical task with the affected hand. Concomitant motor recovery was assessed by measuring the number of thumb-to-index tappings performed in 15 s at each PET session. Across patients, the hemispheric activation balance tended to shift over time toward the unaffected hemisphere, but the magnitude of this shift was highly variable from patient to patient and significantly correlated with recovery. Thus, in subcortical stroke, a shift of activation balance towards the unaffected hemisphere appears associated with lesser initial recovery and, conversely, the more this physiological balance is maintained over time the better the recovery.

Movement-dependent stroke recovery: A systematic review and meta-analysis of TMS and fMRI evidence

“…Increased engagement in the lesioned hemisphere with an activity-based intervention is consistent with studies of natural recovery from stroke which show that individuals with better functional recovery of their upper extremity activate primarily the lesioned hemisphere when using the paretic arm (Calautti et al, 2001;Marshall et al, 2000;Traversa et al, 1997;Traversa et al, 1998;Turton et al, 1996). The significance of these findings contributes to the argument that targeted upper extremity therapy post-stroke can facilitate increased engagement of the lesioned hemisphere during paretic arm movements in individuals with chronic stroke.…”

“…Although still not completely understood, recent research suggests that motor recovery improvements are associated with decreased reliance on recruitment of the intact hemisphere and increased engagement in the lesioned hemisphere (Calautti, Leroy, Guincestre, Marié, & Baron, 2001;Marshall et al, 2000;Traversa, Cicinelli, Bassi, Rossini, & Bernardi, 1997;Traversa, Cicinelli, Pasqualetti, Filippi, & Rossini, 1998;Turton, Wroe, Trepte, Fraser, & Lemon, 1996). These findings indicate that conditions that promote greater neural plasticity within and recruitment of the lesioned hemisphere are likely to foster greater functional recovery of the upper limb.…”

Noninvasive brain stimulation in stroke rehabilitation

“…Increased levels of contralesional sensorimotor activation have been identified during simple movements of the paretic hand. 59,60 The magnitude of contralesional activation appears to decrease in M1 at 3 to 6 months, relative to 1 week after the stroke, 60,32 but the intensity of contralesional M1 activity does not correlate with the degree of recovery. 56 This finding might indicate that contralesional activation is not functionally relevant for recovery, 56 or that it is insufficient to compensate for a marked motor deficit.…”

Functional magnetic resonance imaging: A review of methodological aspects and clinical applications

“…In addition, patients activate the entire sensorimotor system in both hemispheres more than healthy subjects, including secondary motor areas in the premotor cortex (SMA and PmD), additional motor-related areas in the parietal cortex and the frontal operculum, and additional supramodal areas in the dorsolateral prefrontal cortex and the anterior cingulate cortex. Longitudinal studies point to an initial stronger activation (recruitment) of the intact hemisphere with a gradual normalization of the activation pattern over time (92)(93)(94)(95)(96). One way of assessing the functional significance of these reorganizational changes is the use of correlational designs in longitudinal studies.…”