FEASIBILITY OF PROBING CORTICOSPINAL EXCITABILITY IN SEVERAL UPPER LIMB MUSCLES IN STROKE PATIENTS WITH UPPER LIMB MOTOR DEFICIT
Background and Aims: The possibility to evoke a motor response
(MEP) in a hand muscle by transcranial magnetic stimulation (TMS) is a
common proxy of the corticospinal tract integrity after a motor stroke.
However, it is still not clear how many muscles should be studied, and
which muscles are preferable to probe. Here we aimed to investigate
corticospinal excitability in several muscles in stroke patients with upper
limb motor deficit.
Methods: We enrolled 31 stroke patients (15 females, mean 54 [38–83]
y.o, 4 [1–11] months poststroke) with a single clinical episode of stroke
and unilateral hand weakness, assessed by Fugl-Meyer Upper Extremity
Scale. We measured corticospinal excitability in three hand muscles of
the paretic limb and in one muscle in the unaffected hand.
Results: 7 out of 24 patients (29%) with MEPs in the affected hand had
MEPs in just one or two muscles, no significant difference was found
among resting motor thresholds (RMTs) of the affected hand muscles.
While MEP negative patients were all severely affected, patients with
MEPs varied extensively in their paresis level. RMTratio between affected
and unaffected hemispheres was the most correlated parameter with the
motor deficit (CI: 0.75 to0.16; P¼0.005).
Conclusions: Our preliminary results highlight the importance of several
muscles investigation for the purpose of MEP finding to increase the
amount of MEP positive stroke patients, which is crucial for neurorehabilitation
trials. Longitudinal studies are needed to elucidate whether the
difference in corticospinal excitability among muscles has an added value
for recovery prediction.