Daniel T. Barry

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Acoustic myography is the recording of sounds produced by contracting muscle. These sounds become louder with increasing force of contraction. We have compared muscle sounds with surface EMG to monitor the dissociation of electrical from mechanical events (presumably, the loss of excitation-contraction coupling) which occur with motor unit fatigue. Acoustic(More)
Acoustic, force, and compound muscle action-potential signals were recorded simultaneously during maximal isometric twitches of frog gastrocnemius muscles. The onset of sound production occurred after the onset of muscle depolarization but before the onset of external force production. Acoustic waveforms consisted of oscillations that initially increased in(More)
  • D T Barry
  • Electromyography and clinical neurophysiology
  • 1992
Muscle sounds are related to force production, fatigue, and pathology of muscle. However, sound data are frequently contaminated by tremor and motivational artifacts. Also, sound data are frequently reported in transducer-dependent units such as millivolts. To eliminate tremor and motivational artifacts and to obtain data in fundamental,(More)
The changes in mechanical resonant frequency of whole muscles during twitch and tetanic contractions were compared to changes in frequency components of the pressure wave produced by muscles during contraction. Resonant frequencies were determined by imposing sinusoidal length changes on a muscle and observing transverse standing waves when the frequency of(More)
The ratio of acoustic myography (AMG) amplitude to surface electromyography (EMG) amplitude is proposed as a measure of mechanical output compared with electrical activity of the contractile system. AMG to EMG ratios were measured from 16 children with muscle disease diagnosed by clinical criteria, EMG, and/or muscle biopsy. These were compared with the(More)
Skeletal muscle vibrates laterally during voluntary and evoked muscle contractions. We hypothesized that the vibration amplitude from evoked muscle twitches is directly related to evoked twitch force from fatiguing muscle. To test the hypothesis, vibrations produced by evoked muscle twitches were recorded during short (5-second) rest periods as the muscle(More)
The pressure field produced by an isometrically contracting frog gastrocnemius muscle is described by the fluid mechanics equations for a vibrating sphere. The equations predict a pressure amplitude that is proportional to the lateral acceleration of the muscle, inversely proportional to the square of the distance from the muscle, and cosinusoidally related(More)
  • D T Barry
  • Archives of physical medicine and rehabilitation
  • 1991
Skeletal muscle emits acoustic signals during voluntary contraction and during twitches produced by electric stimulation of peripheral nerves. Supramaximal, percutaneous electric stimulation was applied to the median or ulnar nerve, while electric and sound signals were recorded from the abductor pollicis brevis or abductor digiti minimi muscles,(More)