Age dynamic of the motor evoked potential from the tongue in healthy persons.

Our aim was to determine parameters of motor evoked potential (MEP), elicited by the transcranial magnetic stimulation (TMS) from the tongue in healthy persons of different age. 62 neurologically healthy individuals without any speech problems (age range from 2 years old to 75 years, 34 females & 28 males) were enrolled. All underwent diagnostic TMS, single-pulse protocol, 90-sm round coil, Neiro-MS-D device. Coil was placed on Fz point, registration was performed by the surface electrode on the middle line of the tongue. Results. MEPs were of different appearance, but were registered in all cases, its average latency was 7,14±0,63 ms, average amplitude - 1,79±1,09 mV. There were no gender differences. Significant age difference (p<0,001) was registered between children (age 2-17 years) and two older groups (18-55 and 56-75 years) both on latency and on amplitude. MEPs latency was in three age groups, respectively, 6,21±0,45; 7,05±0,76, and 7,27±0,64 ms. MEPs amplitudes were 0,81±0,61; 1,88±1,01 and 1,69±0,92 mV, respectively. In healthy people aged 2-75 years MEP from the tongue may be registered in 100% of the cases; its average latency is 7,14±0,63 ms, average amplitude - 1,79±1,09 mV; there are no significant gender differences, but significant age differences. TMS of the tongue according to this protocol is relatively simple, not time-and efforts-consuming & may be widely implemented in clinical neurophysiology. There are significant differences on MEPs latencies and amplitudes in healthy persons, which may reflect age-related changes - lengthening of the cortico-lingual pathways and tongue muscle maturing in the childhood and then fibrous tissue development and other changes in nervous tissue and tongue muscle, developing with age.