Effects of Wrist Tendon Vibration on Targeted Upper-Arm Movements in Poststroke Hemiparesis

Abstract

Abstract:Background. Impaired motor control of the upper extremity after stroke may be related to lost sensory, motor, and integrative functions of the brain. Artificial activation of sensory afferents might improve control of movement by adding excitatory drive to sensorimotor control structures. The authors evaluated the effect of wrist tendon vibration (TV) on paretic upper-arm stability during point-to-point planar movements. Methods. TV (70 Hz) was applied to the forearm wrist musculature of 10 hemiparetic stroke patients as they made center-out planar arm movements. End-point stability, muscle activity, and grip pressure were compared as patients stabilized at the target NOT THE PUBLISHED VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page.Neurorehabilitation and Neural Repair, Vol 25, No. 1 (January 2011): pg. 61-70. DOI. This article is © SAGE Publications and permission has been granted for this version to appear in e-Publications@Marquette. SAGE Publications does not grant permission for this article to be further copied/distributed or hosted elsewhere without the express permission from SAGE Publications.2 position for trials completed before, during, and after the application of the vibratory stimulus. Results. Prior to vibration, hand position fluctuated as participants attempted to maintain the hand at the target after movement termination. TV improved arm stability, as evidenced by decreased magnitude of hand tangential velocity at the target. Improved stability was accompanied by a decrease in muscle activity throughout the arm as well as a mean decrease in grip pressure. Conclusions. These results suggest that vibratory stimulation of the distal wrist musculature enhances stability of the proximal arm and can be studied further as a mode for improving end-point stability during reaching in hemiparetic patients.

Immediate effects of somatosensory stimulation on hand function in patients with poststroke hemiparesis

“…Moreover, another assumption of vibration effects is caused by repetitive tactile stimulation on skin, which results in benefits from synchronous activation in neural afferents and cortical neurons and influences the connectivity of cortical neurons in the sensory cortex with the neural network of other cortices (Freyer et al, 2012). After vibration stimulation, increased cortical excitability has been evidenced by numerous neuroscientific studies (Conrad et al, 2011). Such a neurophysiological correlation may be the possible mechanism for long-term potentiation derived from alterations in the strength of the corticocortical connections (Hoogendam et al, 2010).…”

“…Enhanced cortical activity of the motor area may be a contributing factor to enhance the fidelity of movement control during the initial phase of rehabilitation such as the feedforward mechanism and anticipatory motor control. Subsequently, spinal reflex systems may be effectively modulated by facilitation in descending cortical control (Conrad et al, 2011). The reinforcement of cortical activation contributes toward the increase in motorevoked potential and decrease in latency of the vibrated muscle, which is observed early after the onset of the vibration (Christova et al, 2011).…”

“…Patients were asked to sit in a chair with their elbow flexed 90°and forearm supinated. All the sensory stimulation procedures were performed on the volar surface of the hand and forearm of the affected side for 5 min (30 trials of sensory stimulation at a moving speed averaging 0.05 m/s) by applying the stimulation from the finger tips, palm, and wrist to forearm (distal to proximal) to stimulate underlying superficial and deep sensory receptors, as suggested by the somatosensory testing procedure (Conrad et al, 2011). Vibration was applied at a frequency of 80 Hz using a vibration device (Thrive MD-01; Thrive Co. Ltd, Osaka, Japan).…”

“…Previous studies have reported the functional benefits of somatosensory stimulation using warm and cold agents (Kawahira et al, 2010), tactile objects (Overvliet et al, 2011), and a vibration device (Conrad et al, 2011). Also, a neuroscientific study supported the use of repeated somatosensory stimulation to facilitate neural plasticity and cortical reorganization (Kalisch et al, 2010), and an EMG study found that the effects of somatosensory stimulation reduce the physiological latency in muscle contraction and increases muscle activity .…”

Effects of Hand Vibration on Motor Output in Chronic Hemiparesis

“…Increased amplitude and a decreased latency of the MEP generated by TMS have been observed during vibration [8,9]. Moreover, there are reports of changes in voluntary force production during and after vibration in healthy [10] and stroke [11] subjects and in motor function in patients with neurological diseases [12,13]. Thus, in the present study, 80 Hz muscle vibration was applied to explore the use of a strong sensory input to improve motor output in hemiparetic subjects.…”