Determining the appropriate stimulus intensity for studying the dipole moment in somatosensory evoked fields: a preliminary study.
OBJECTIVE
To establish a simple method of determining the appropriate stimulus intensity for studying the dipole moment in somatosensory evoked fields.


METHODS
In 17 patients (20 hemispheres), the authors studied the relationship between the dipole moment and stimulus intensity, which was quantified using the threshold of thenar muscle twitch (TMT). The dipole moment was measured at 1.0, 1.5 and 2.0 TMT. Two measurements were obtained at 1.5 TMT to determine the procedure's margin of error.


RESULTS
There was no significant difference between the dipole moments measured at 1.5 and 2.0 TMT.


CONCLUSIONS
Setting the stimulus intensity at 1.5 TMT or more ensures a consistent response.
Tsutada
T
T
Department of Geriatrics and Neurology, Osaka City University Medical School, Osaka, Japan. tsutada@usa.net
Tsuyuguchi
N
N
Hattori
H
H
Shimada
H
H
Shimogawara
M
M
Kuramoto
T
T
Haruta
Y
Y
Matsuoka
Y
Y
Hakuba
A
A
D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000502:physiology*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged