Reference : Ipsilateral motor responses to focal transcranial magnetic stimulation in healthy sub...
Scientific journals : Article
Human health sciences : Neurology
Ipsilateral motor responses to focal transcranial magnetic stimulation in healthy subjects and acute-stroke patients
Alagona, Giovanna [> >]
DELVAUX, Valérie mailto [Centre Hospitalier Universitaire de Liège - CHU > > Neurologie Sart Tilman >]
GERARD, Pascale [Centre Hospitalier Universitaire de Liège - CHU > > Neurologie CHR >]
DE PASQUA, Victor [Centre Hospitalier Universitaire de Liège - CHU > > Neurologie CHR >]
PENNISI, Giovanni [> >]
Delwaide, Paul mailto [Université de Liège - ULiège > Services généraux (Faculté de médecine) > Relations académiques et scientifiques (Médecine) >]
Nicoletti, Fr [> >]
MAERTENS DE NOORDHOUT, Alain mailto [Centre Hospitalier Universitaire de Liège - CHU > > Neurologie CHR >]
Lippincott Williams & Wilkins
Yes (verified by ORBi)
[en] magnetic stimulation ; stroke ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cerebral Cortex/physiology/physiopathology ; Electric Stimulation/instrumentation ; Electromyography ; Evoked Potentials, Motor ; Female ; Functional Laterality ; Hand Strength ; Humans ; Male ; Middle Aged ; Motor Skills ; Muscle, Skeletal/innervation ; Neuronal Plasticity ; Pyramidal Tracts/physiology/physiopathology ; Reaction Time ; Recovery of Function ; Severity of Illness Index ; Stroke/diagnosis/physiopathology/rehabilitation ; Transcranial Magnetic Stimulation
[en] BACKGROUND AND PURPOSE: Prevalence and characteristics of ipsilateral upper limb motor-evoked potentials (MEPs) elicited by focal transcranial magnetic stimulation (TMS) were compared in healthy subjects and patients with acute stroke. METHODS: Sixteen healthy subjects and 25 patients with acute stroke underwent focal TMS at maximum stimulator output over motor and premotor cortices. If present, MEPs evoked in muscles ipsilateral to TMS were analyzed for latency, amplitude, shape, and center of gravity (ie, preferential coil location to elicit them). In stroke patients, possible relationships between early ipsilateral responses and functional outcome at 6 months were sought. RESULTS: With relaxed or slightly contracting target muscle, maximal TMS over the motor cortex failed to elicit ipsilateral MEPs in the first dorsal interosseous (FDI) or biceps of any of 16 normal subjects. In 5 of 8 healthy subjects tested, ipsilateral MEPs with latencies longer than contralateral MEPs were evoked in FDI muscle (in biceps, 6 of 8 subjects) during strong (>50% maximum) contraction of the target muscle. In 15 of 25 stroke patients, ipsilateral MEPs in the unaffected relaxed FDI (in biceps, 6 of 25 stroke patients) were evoked by stimulation of premotor areas of the affected hemisphere. Their latencies were shorter than those that MEPs evoked in the same muscle by stimulation of the motor cortex of the contralateral unaffected hemisphere. Such responses were never obtained in normal subjects and were mostly observed in patients with subcortical infarcts. Patients harboring these responses had slightly better bimanual dexterity after 6 months. CONCLUSIONS: Ipsilateral MEPs obtained in healthy individuals and stroke patients have different characteristics and probably different origins. In the former, they are probably conveyed via corticoreticulospinal or corticopropriospinal pathways, whereas in the latter, early ipsilateral MEPs could originate in hyperexcitable premotor areas.

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