title: The effect of vocalization on spinal excitation as measured by H wave.
abstract: The aim of this study was to measure the H wave by using voice-activated electromyography to reveal how different speech outputs affect the spinal cord segments innervating the lower limb skeletal muscles. In 21 healthy adults (16 men and 5 women) seated in a semi-reclined position, the H wave was recorded using surface electrodes over the soleus muscle of the pivot leg after stimulating the tibial nerve. The amplitude of the H wave was 1.02 SD 0.69 mV under the pre-vocalization condition; 1.51 SD 0.76 mV under the submaximal vocalization condition (≥60-<80 dB); and 1.13 SD 0.59 mV under the maximal vocalization condition (≥80 dB), demonstrating that the amplitude generated with submaximal vocalization was significantly higher than the control and maximal vocalization conditions. Mean voice intensity was around 69 dB for submaximal vocalization and around 91 dB for maximal vocalization. Submaximal vocalization results in a higher H wave amplitude than the control condition, thus suggesting increased spinal cord excitation, which may be important for initiating activities of daily living (e.g., lifting objects) or mobility (e.g., moving from a sitting to a standing position).
authors.affiliation: a School of Physiotherapy, Koriyama Institute of Health Sciences , Koriyama , Japan.|b Interdisciplinary Graduate School of Science and Technology, Shinshu University , Ueda, Nagano , Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Furukawa
authors.affiliation: b Interdisciplinary Graduate School of Science and Technology, Shinshu University , Ueda, Nagano , Japan.|c Koriyama Institute of Health Sciences , Koriyama , Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: b Interdisciplinary Graduate School of Science and Technology, Shinshu University , Ueda, Nagano , Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
authors.affiliation: b Interdisciplinary Graduate School of Science and Technology, Shinshu University , Ueda, Nagano , Japan.
authors.forename: Masayosi
authors.initials: M
authors.lastname: Kamijo
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods*; D005260:Female; D006181:H-Reflex; D006801:Humans; D035002:Lower Extremity; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation*; D056888:Patient Positioning; D010699:Phonation; D013116:Spinal Cord / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*; D014831:Voice; D055815:Young Adult
keywords: H wave; phonation effect; spinal cord excitability level; therapeutic exercise