The effect of head and neck positions on oropharyngeal swallowing: a clinical and electrophysiologic study.

OBJECTIVES: To determine the clinical usefulness of an electrophysiologic method for evaluating dysphagia and to identify the effects of various head and neck positions on oropharyngeal swallowing. DESIGN: Experimental, with control group. SETTING: An electromyography laboratory. PARTICIPANTS: Patients with neurogenic dysphagia (n = 51) and healthy controls (n = 24). Patients were divided into 2 groups: those patients with unilateral lower cranial lesions (n = 9) and those without laterality in the function of the oropharyngeal muscles (n = 42). INTERVENTIONS: Subjects were instructed to swallow doses of water, gradually increasing in quantity from 1 to 25 mL under 5 conditions: neutral, chin up, chin tucked, head rotated right, and head rotated left. MAIN OUTCOME MEASURES: Change in dysphagia limit through specified head and neck postures. Oropharyngeal swallowing was evaluated by laryngeal movements that were detected by a piezoelectric sensor and electromyography of the submental muscle complex. Laryngeal sensor signals occurring within 8 seconds of a swallow were accepted as a sign of the dysphagia limit. RESULTS: In the control group, dysphagia limit did not change significantly with changes in head and neck postures, except for the chin-up posture (p <.05) in which piecemeal deglutition occurred when subjects swallowed volumes less than 20 mL. Dysphagia limit improved significantly (p <.05) in 67% of the patients with unilateral lower cranial lesions when the head was rotated toward the paretic side. In dysphagic patients with bilateral symptoms, a significant (p <.01) improvement in dysphagia limit occurred in 50% of patients in chin-tuck position, but in the chin-up position, 55% of the patients experienced a significant (p <.01) decrease in dysphagia limit. CONCLUSION: The electrophysiologic method of measuring dysphagia limit confirms neurogenic dysphagia and its severity in the neutral head position. Changes in head and neck positions do not significantly alter dysphagia limit in unimpaired subjects except for the chin-up position. Although the results obtained were not compared with other techniques (eg, videofluoroscopy), this simple electrophysiologic method for describing dysphagia limit may have a place in the evaluation of dysphagia and its variability in various head and neck positions.

Tourniquet paralysis after primary nerve repair.

Paralysis after use of a tourniquet during surgery is a well recognized complication. Based on the electrophysiologic findings, 35 cases referred to our electromyography laboratory have been diagnosed as tourniquet paralysis within a 3-yr period. This preliminary report suggests that tourniquet paralysis should be considered during clinical and electrophysiologic evaluations after primary nerve repairs.

Mechanisms of action of phenol block and botulinus toxin Type A in relieving spasticity: electrophysiologic investigation and follow-up.

This preliminary study was designed to investigate the effects of botulinus toxin Type A and phenol treatments on electrophysiologic tests evaluating spinal afferent and efferent motor pathways involved in spasticity. The questions posed were whether different types of mechanisms act on reducing spasticity with these different treatment modalities and whether the tests are correlated with clinical recovery. Twenty patients with lower limb spasticity secondary to stroke were randomly assigned to receive 400 mouse units of botulinus toxin Type A injected into the calf muscles or to receive a tibial nerve blockade with 3 ml of 5% phenol. The amplitudes of the Achilles tendon response, M response, H reflex response, and maximum H:M ratio and Achilles tendon response to H response ratio were recorded from the soleus muscle at baseline and at Weeks 2, 4, and 12. The most obvious change was a reduction in the amplitude of the tendon response in the group that received botulinus toxin Type A, and it was a reduction in the M response amplitude in the group that received phenol. The decrease in the tendon response amplitude and tendon response to H ratio in the group that received botulinus toxin Type A and the decrease in the M response amplitude in the phenol group were found to be well correlated with clinical recovery as assessed by the Ashworth scale. The findings suggested that botulinus toxin Type A injection decreases spasticity primarily by affecting the fusimotor system and muscle spindle, and the involvement of the alpha-motor fibers within the tibial nerve is the most likely factor contributing to the reduction of spasticity after phenol blockade. The therapeutic effectiveness of these agents could be assessed and followed up by the changes in electrophysiologic responses matching their mechanisms of action. The findings should be supported by further electrophysiologic techniques.

Comparison of phenol block and botulinus toxin type A in the treatment of spastic foot after stroke: a randomized, double-blind trial.

Locally acting treatments for spasticity such as nerve and motor point blocks have the advantage of reducing harmful spasticity in one area, while preserving useful spasticity in another area. This randomized, double-blind study is the first trial that was designed to find out whether botulinus toxin Type A and phenol relieves the signs and symptoms of ankle plantar flexor and foot invertor spasticity after stroke and if either of these methods offers any advantages and disadvantages over the other. Twenty patients who were included in this preliminary study were randomly assigned to receive a single treatment of 400 mouse units of botulinus toxin Type A injected into the calf muscles or to receive a tibial nerve blockade with 3 ml of 5% phenol. A combination of subjective and objective measures were used to assess functional change at baseline and at Weeks 2, 4, 8, and 12. At follow-up, significant improvement (P < 0.05) in the Ashworth score for dorsiflexion was observed in both groups. The change in the Ashworth score for eversion was significant in the group that received botulinus toxin Type A (P < 0.05) but not in the group that received phenol (P > 0.05). When those variables were compared between the two groups, the change in the Ashworth score at Weeks 2 and 4 was significantly better in the group that received botulinus toxin Type A (P < 0.05) but there was not a significant difference between the two groups at Weeks 8 and 12 (P > 0.05). The decrease in clonus duration that was detected by electromyography was significant in both groups at all visits, but the decrease in the group that received botulinus toxin Type A was significantly better at Weeks 2 and 4 (P < 0.05). It is concluded that both motor point injections with botulinus toxin Type A and tibial nerve blockade with phenol are effective in plantar flexor spasticity, but the changes were more significant in the group that received botulinus toxin Type A at Weeks 2 and 4, whereas there was not a significant difference between the two groups at Weeks 8 and 12. Future research should explore the long-term effect of these two treatment modalities.

Local heat effect on sympathetic skin responses after pain of electrical stimulus.

OBJECTIVE: To investigate the analgesic effort of local superficial heating by studying sympathetic skin responses. DESIGN: Randomized trial. SETTING: Electromyography laboratory in the department of physical therapy and rehabilitation of a university hospital. SUBJECTS: Twenty healthy volunteers participated with informed consent. INTERVENTIONS: Sympathetic skin response (SSR) amplitudes following electrical stimulation of the right peroneal nerve and skin temperatures in both hands were recorded simultaneously. All of the recordings were repeated at 5-minute intervals during local heat application over the right palm and within 15 minutes after heat application was stopped. RESULTS: SSR amplitudes in both hands decreased significantly during local heating (p < .05) and did not return to their initial levels within 15 minutes of the recovery period; the reductions remained statistically significant (p < .05). Amplitude reductions were statistically more significant on the heated hand compared with those on the contralateral hand (p < .05). CONCLUSION: Therapeutic local heat application reduces the sudomotor response to a painful stimulus. This analgesic effect may be due to suppression of cortical pain sensation resulting from increased levels of endorphins, and may also be a result of local inhibition of both afferent and efferent C fibres.

Ulnar nerve lesion in the palm: report of an unusual case.

We report the case of a patient who had weakness of the fourth dorsal interosseous (DI) and third palmar interosseous (PI) muscles resulting in the abducted position of the little finger at rest. Electromyographic abnormalities were limited to only these muscles with partial denervation findings. The results of routine nerve conduction studies and imaging techniques were normal. Clinical and electrophysiological findings suggested that the lesion had occurred distal to the point where the very small motor branches to these muscles exit the deep palmar branch of the ulnar nerve.