Reliability of a novel neurostimulation method to study involuntary muscle phenomena

Abstract

Experimental methods involving painful electrical stimulation of a peripheral nerve showed the existence of a minimum stimulation frequency capable of inducing cramp, termed "threshold frequency" (TF). Our aim was to test an alternative method to induce fasciculations and cramps electrically. Two daily sessions of electrical stimulation of the abductor hallucis muscle were performed in 19 volunteers on 3 days: stimulation trains of 150 monophasic square pulses (duration 152 s) of increasing frequency (current intensity 30% higher than maximal; frequency of the first trial, 4 pps; recovery between trials, 1 min) were delivered to the main muscle motor point until a cramp developed. Once a cramp was induced the protocol was repeated after 30 min. To verify by electromyography that cramp occurred, a surface electrode array was placed between the motor point and the distal tendon. Ambient and skin temperature were kept constant in all sessions. Fasciculations and cramps were elicited in all subjects. We observed the following median (interquartile range) values of TF: day 1 (session 1), 13 (6) pps; day 1 (session 2), 16 (4) pps; day 2 (session 1), 16 (6) pps; day 2 (session 2), 18 (6) pps; day 3 (session 1), 17 (4) pps; day 3 (session 2), 18 (8) pps. TF intersession intraclass correlation coefficients were 0.82, 0.92, and 0.90 for days 1, 2, and 3, respectively. TF interday intraclass correlation coefficient was 0.85. The absence of pain due to the stimulation and the demonstration of TF reliability support the use of our method for the study of involuntary muscle phenomena.

Strengthening and Neuromuscular Reeducation of the Gluteus Maximus in a Triathlete with Exercise-Associated Cramping of the Hamstrings

“…This increase in excitatory responses (type Ia, II) and decrease in inhibitory responses (type Ib/Golgi tendon organs) has been hypothesized to result in sustained alpha motor neuron activity indicative of muscle cramping. 2,22,[28][29][30] Evidence suggests that EAMC also can be caused by an electrolyte deficit. Electrolyte deficit is caused by excessive sweating, leading to a loss of sodium and/ or chloride, as well as a decrease in plasma volume.…”

Neural Mechanisms of Muscle Cramp

“…Therefore, electrical stimulation is often applied directly to the muscle motor point. This produces less pain, and has been developed as an alternative to peripheral nerve stimulation and has been utilized (Minetto and Botter 2009;Minetto et al 2008Minetto et al , 2009aMinetto et al , b, 2011. A study with the motor point stimulation demonstrated that the threshold frequency and pain in intrinsic foot muscle were lower than those in leg muscle.…”

Електроміографічна Діагностика Порушень Моторики Язика Неврологічного Генезу У Пацієнтів З Оклюзійною Патологією

“…Пошире-ним методом діагностики розладів функціонування м'язів є поверхнева електроміографія [15][16][17][18]. Най-більш вивченою у стоматології є методика електро-міографії жувальних м'язів.…”