Objective
To dete
rmine the int
ra- and inte
r-session
reliability of
moto
r evoked potential (MEP) size pa
ra
mete
rs in the lowe
r li
mb of patients with st
roke, focussing on the nu
mbe
r of MEPs collected and the
method of
measu
ring MEP size.
Methods
Transcranial magnetic stimulation was used to elicit MEPs in the soleus muscle of patients with stroke (m>nm> = 13) and age-matched healthy participants (m>nm> = 13) during low level muscle activation. Two sets of 10 responses were collected in the first session and a further 10 responses collected in a second session held 7 days later. Four MEP size measurements were made using 4, 6, 8, or all 10 of the MEPs collected. Intra- and inter-session reliability was examined using intraclass correlation coefficients (ICC) and typical percentage error.
Results
Intrasession ICC statistics using 6 or more MEPs were >0.85 in the stroke group but intersession values were all <0.5. Reliability was best when measuring parameters from individual MEPs rather than averaged responses.
Conclusions
Reliability of intrasession MEP size is excellent in the lower limb of patients with stroke using as few as 6 MEPs but intersession reliability is poor.
Significance
Comparing MEP size measures across two or more sessions is questionable in the lower limb of patients with stroke.