Effects of differences in age and body height on normal values of central motor conduction time determined by F-waves

Abstract

Objectives: To investigate the effect on central motor conduction time (CMCT) based on the relationship between age and height in normal subjects. Design: Retrospective study. Methods: One hundred and ninety nine normal subjects (107 men and 92 women; mean age 39.0 ± 16.4 years; mean height 164.5 ± 8.8 cm) participated in the study. The approximate ages of subjects were as follows: 82 (20-29 years old), 32 (30-39 years old), 32 (40-49 years old), 28 (50-59 years old), and 25 (≧60 years old). The heights of 9, 49, 79, 53, and 9 subjects were <150 cm, 150-160 cm, 160-170 cm, 170-180 cm, and >180 cm, respectively. CMCT-abductor digiti minimi (ADM) and abductor hallucis (AH) were calculated by subtracting the peripheral motor conduction time (PMCT) from the onset latency of motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation. PMCT was calculated from the latencies of the compound muscle action potentials (CMAPs) and F-waves as follows: (latency of CMAPs + latency of F-waves -1)/2. Outcome measures: CMCT-ADM and CMCT-AH. Results:The normative values were 5.2 ± 0.8 ms and 11.8 ± 1.3 ms for CMCT-ADM and CMCT-AH, respectively. CMCT-ADM was not significantly correlated with age (P = 0.196) and body height (P = 0.158). CMCT-AH had significantly positive, linear correlations with age and body height (CMCT-AH = 0.014 × age + 10.971, P = 0.011, R = 0.179 and CMCT-AH = 0.026 × body height + 7.158, P = 0.010, R = 0.182). Conclusions: We suggest normative values of 3.2-7.2 ms in CMCT-ADM for subjects exerting slight effort on ADM regardless age and body height. CMCT-AH had significantly positive, linear correlations with age and body height.

Utility of the central motor conduction time recorded from the abductor pollicis brevis and the abductor digiti minimi muscles in patients with C6–7 myelopathy

“…The ADM control data came from a previously published study. 1 No significant correlations were found between the CMCT-APB and the CMCT-ADM (CMCT-APB -CMCT-ADM) = 0.1±1.0 ms (P = 0.44).…”

“…The central motor conduction time (CMCT) has been used to electrophysiologically evaluate corticospinal tract function and is very useful for diagnosing corticospinal tract disorders. [1][2][3][4] Measurement of the CMCT is noninvasive and safe for investigating lateral corticospinal tract function. In our previous study, we found a systematic correlation between the CMCT recorded from the abductor digiti minimi (ADM; CMCT-ADM) and the responsible level of cervical compressive myelopathy (CCM).…”

The Promotoer, a brain-computer interface-assisted intervention to promote upper limb functional motor recovery after stroke: a study protocol for a randomized controlled trial to test early and long-term efficacy and to identify determinants of response

“…the Motor Evoked Potentials (MEPs) to evaluate the corticospinal tract integrity at screening (T(− 1)); MEPs will be recorded from the bilateral Abductor Digiti Minimi (ADM) muscle by following the methodology reported in [29]. In brief, TMS will be delivered in single stimuli at maximum output stimulator (5 stimuli for each side) and electromyographical (EMG) activity will be recorded from ADM muscle bilaterally, if allowed during voluntary contraction.…”

Amyotrophic lateral sclerosis weakens spinal recurrent inhibition and post-activation depression

“…UMN involvement was defined based on the findings of increased/hyperactive deep tendon reflexes (DTR) and/or pathological reflexes (i.e., in the upper extremity: palmomental and Hoffmann signs, and in the lower extremity: Babinski sign), in the neurological examination or abnormal findings in transcranial magnetic stimulation (TMS), i.e., absent or reduced motor evoked potential or prolonged central motor conduction time adjusted to the height of the subject (Groppa et al, 2012;Imajo et al, 2017). DTR was determined according to DTR scale (0: no response, 1+: sluggish, 2+: normal, 3+: slightly hyperactive/brisk, 4+: abnormally hyperactive with intermittent clonus) (Seidel et al, 2011).…”