Motor Strokes

Abstract

Background and Purpose-The purpose of this research was to investigate the impact of lesion location on motor excitability and motor performance. Methods-We studied patients with pure motor strokes in 4 different brain areas: motor cortex lesions (nϭ7), striatocapsular lesions (nϭ13), lacunar lesions of the internal capsule (nϭ13), and paramedian pontine lesions (nϭ10). Motor performance tests included the 9-hole-peg test and grip strength recordings. Motor excitability was determined by transcranial magnetic stimulation. Motor thresholds, stimulus-response curves, silent periods, motor cortical inhibition, and facilitation were investigated. Results-The 4 groups were clinically similar but showed major differences in motor excitability. Only motor cortex lesions had a loss of intracortical inhibition in the affected hemisphere. In the internal capsule lesion group and the pontine lesion group, stimulus-response curves were depressed on the affected side. All of the subcortical lesions showed a prolongation of the silent period in the paretic side. Motor thresholds were predominantly elevated in the lesioned hemisphere of patients with internal capsule or pontine lesions. Motor performance was correlated with silent period duration in internal capsule lesions and with motor thresholds in internal capsule and pontine lesions. Conclusions-Motor

Bilateral Versus Unilateral Upper Extremity Training on Upper Limb Motor Activity in Hemiplegia

“…Quality of Movement between the two training groups did not differ significantly which could have been due to the diverse extent of damage to the corticospinal pathways in the study subjects. Similar findings were reported by Ward NS et al [61] Liepert et al [62] and Hamzei et al [63] who noted the impact of extent and location of lesion on motor cortex excitability respectively.…”

Repetitive Transcranial Magnetic Stimulation–Induced Corticomotor Excitability and Associated Motor Skill Acquisition in Chronic Stroke

“…1,2 The affected motor cortex of the stroke patients shows a reduced cortical excitability 3,4 and a suppression of the topographical representation of the affected muscles, whereas the unaffected motor cortex shows increased excitability and an enlarged cortical motor output. [5][6][7] Depending on the frequency range, inhibitory and facilitatory modulation effects have been suggested to occur when rTMS is applied to the hand motor cortex.…”

Abnormal Motor Cortex Excitability in Congenital Stroke

“…Reduction of SICI in the affected hemisphere as it has been shown in adult patients investigated in the postacute stage (12)(13)(14)(15) as well as in chronic stage after stroke (38) might reflect a reduced number of GABAergic interneurons, which can be recruited due to the lesion. This is supported by the finding that SICI was eliminated in adults with stroke involving the motor cortex but not in patients with internal capsule, pontine, or striatocapsular lesions (15).…”

“…Until now, studies investigating intracortical excitability by transcranial magnetic paired pulse stimulation have been conducted only in patients with adulthood stroke (12)(13)(14)(15). This technique allows us to study changes in the excitability of both inhibitory and excitatory intracortical circuits, a mechanism credited to be involved in reorganization of the brain (16 -19).…”

“…This technique allows us to study changes in the excitability of both inhibitory and excitatory intracortical circuits, a mechanism credited to be involved in reorganization of the brain (16 -19). In adulthood, cortical stroke intracortical excitability is increased, as indicated by a reduced intracortical inhibition with a heightened amplitude of the conditioned motor evoked potential (MEP) (12)(13)(14)(15). There is evidence from developmental studies that corticospinal excitability as well as intracortical excitability are age dependent and are not fully established up to several years postnatally (20 -23).…”