Method: Sixteen stroke and traumatic brain injured subjects participated in this study. Electrical stimulation on the dermatome of spastic muscles was applied for 30 minutes a day for 4 weeks. Spasticity was quantified through the use of a relaxation index obtained from pendulum test and a amplitude and latency from knee tendon reflex test. The measurements were performed 6 times in treatment period. The data were analyzed by repeated measures one way ANOVA.

Results: Relaxation index was significantly increased in treatment period (p＜0.05). In each therapeutic stimulation session, relaxation index of post-stimulation was increased in comparison with that of pre-stimulation (p＜0.01). The amplitude of post-stimulation was significantly decreased in comparison with pre-stimulation status in each measurement session (p＜0.01). The latency of tendon reflex was not changed after stimulation.

Conclusion: These results showed that the electrical stimulation was useful method to decrease spasticity in patients with brain lesions. Further studies are needed to explore the effects of functional improvement and the long-lasting carryover effects on spasticity in electrical stimulation. (J Korean Acad Rehab Med 2003; 27: 27-32)

Objective: To evaluate the usefulness of the sural/superficial radial sensory nerve action potential amplitude ratio (SRAR) in the electrodiagnosis of diabetic polyneuropathy.

Method: Nerve conduction study was performed in 80 diabetic patients and 31 normal adults. Standard nerve conduction studies were performed. Sural nerve response was recorded with the active electrode on the posterosuperior margin of the lateral malleolus and stimulation 14 cm proximally. Superficial radial nerve response was recorded with the active on the snuffbox and stimulation 10 cm proximally. Baseline-to-peak sensory nerve action potential (SNAP) amplitudes were measured, and SRAR were obtained. The diabetic group was subdivided into an electrophysiologically normal group (DMNL, n=32) and neuro-

pathy group (DMPN, n=48). SRAR was compared among the control (NORM, n=31), DMNL and DMPN groups.

Results: SRAR was 0.344 in NORM, 0.314 in DMNL and 0.145 in DMPN, respectively. SRAR showed 77.1% sensitivity and 93.8% specificity. Sural SNAP amplitude sensitivity was 85.4% and specificity, 88.7%.

Conclusion: The relatively high specificity of SRAR indicates its usefulness in the diagnosis of diabetic polyneuropathy. However, as the superficial radial sensory SNAP amplitude decreased significantly in the diabetic groups compared to control, the SRAR is not superior to the sural SNAP amplitude in the diagnosis of diabetic polyneuropathy. (J Korean Acad Rehab Med 2002; 26: 147-151)

Objective: The purpose of this study is to find out whether amplitude ratio and area ratio have correlation with nerve conduction velocity in the diabetes mellitus patients.

Method: Median and deep peroneal motor nerve conduction study was performed in thirty-five normal control group and sixty diabetes mellitus patients group. The motor conduction velocity, amplitude ratio, and area ratio of the compound muscle action potential (CMAP) were measured. The experimental subjects were divided into 6 subgroups (in median nerve: M1, M2, M3, in peroneal nerve: P1, P2, P3) according to the median value of conduction velocity of each nerve; group M1 (n=35) and P1 (n=30): normal control group, group M2 (n=25) and P2 (n=30): below the median value of motor nerve conduction velocity in diabetes mellitus patients, group M3 (n=23) and P3 (n=29): above the median value of motor nerve conduction velocity in diabetes mellitus patients.

Results: There was no significant difference of area ratio between the each subgroups in both median and peroneal nerves. There was a significant difference of amplitude ratio between the M1 and M2 subgroups. There was a significant difference of amplitude ratio between the P1 and P2, P3 subgroups.

Conclusion: According to above results, the decrease of amplitude of compound muscle action potential along with the decrease of conduction velocity seems to be helpful in the electrophysiologic diagnosis of diabetic neuropathy.

Objective: Distance between the active and reference electrodes can affect the waveform configuration and amplitude of sensory nerve action potential (SNAP). This study was purposed to determine the change of SNAP parameters with varying interelectrode distance.

Metohod: Median sensory nerve conduction study was performed in the middle finger of 40 young healthy subjects by antidromic method. To ensure firm contact with skin, strip adhesive electrode was used for recording responses. The active electrode was fixed on 1 cm distal to the proximal flexion crease of middle finger and interelectrode separation was increased from 1 to 5 cm by 1.0 cm increments. Bar electrode was fixed 14 cm proximal from active electrode for stimulation in the wrist area.

Results: As the interelectrode distance increased from 1 cm to 5 cm, onset latency remained unchanged. The peak latency increased with increasing the distance up to 3 cm but didn't change beyond 3 cm (1 cm: 2.89⁑0.89 msec, 2 cm: 2.97⁑0.89 msec, 3 cm: 3.02⁑0.19 msec, 4 cm: 3.02⁑0.19 msec, 5 cm: 3.02⁑0.20 msec). Base-to-peak amplitude significantly increased only up to 3 cm (1 cm: 30.3⁑6.7μV, 2 cm: 43.7⁑8.6μV, 3 cm: 50.8⁑10.4μV, 4 cm: 51.1⁑10.9 μV, 5c m: 51.3⁑11.4μV) but peak-to-peak amplitude sequentially increased to 5 cm (1 cm: 49.6⁑12.1μV, 2 cm: 72.8⁑14.4μv, 3 cm: 83.6⁑19.4μV, 4 cm: 91.3⁑22.5μV, 5 cm: 93.4⁑23.9μV)(p＜.05).

Conclustion: This study showed that changing interelectrode distance altered some parameters of SNAP, especially the peak-to peak amplitude.

Objective: To obtain reference values of early potential latency and amplitude of pudendal SEP in Korean normal women and to correlate those values with height and age.

Method: Twenty-three normal female with mean age of 45.27 years were evaluated for pudendal SEP. Stimulation was applied on the dorsal aspect of the clitoris with a bar electrode. Onset, P1, N1, P2 latencies and P0-P1, P1-N1, N1-P2 amplitudes were measured and those of both sides were analyzed.

Results: The mean latency of P0, P1, N1, P2 were 29.0⁑2.83 msec, 35.5⁑2.91 msec, 45.1⁑4.10 msec, 56.3⁑5.20 msec by the right pudendal nerve, and 28.6⁑3.11 msec, 35.2⁑2.93 msec, 45.0⁑3.83 msec, 56.5⁑5.33 msec by the left pudendal nerve. The amplitude ranges of P0-P1, P1-N1, N1-P2 were 0.31∼2.45 uV, 0.11∼2.24 uV, 0.21∼2.62 uV by the right pudendal nerve, and 0.29∼2.46 uV, 0.25∼2.21 uV, 0.12∼5.07 uV by the left pudendal nerve. There was tendency of prolongation of the latency with increasing the height. There is no difference of amplitude according to the height and the age. There was no significant difference between right and left sides in mean latency and range of amplitude of pudendal nerve SEPs, and between premenopause and postmenopause.

Conclusion: Normal reference of female pudendal SEP were established. We suggest that pudendal SEP can be used as one of useful diagnostic tools for female urogenital and neurologic disease.

Objective: To demonstrate a conduction block of the median nerve at the flexor retinaculum (FR) in carpal tunnel syndrome (CTS), comparison of potentials obtained with stimulation of median nerve at the wrist and the palm may be required.

Method: To determine the severity and incidence of conduction block in patients with CTS, seventy hands of neurologically healthy adults (mean age, 48 years) as control, and seventy hands of patients with CTS (mean age, 51 years) were tested. We performed median motor and middle finger recorded antidromic sensory conduction study with stimulation of the wrist and palm of a distance of 5 cm. The negative peak spike duration and baseline to peak amplitude of the compound muscle action potential (CMAP), and sensory nerve action potential (SNAP) with wrist and palm stimulations were measured. From these values, the wrist to palm duration ratio and amplitude ratio were obtained.

Results: The criteria of median motor nerve conduction block were a wrist to palm amplitude ratio of less than 0.7 and a wrist to palm duration ratio of less than 1.13. The criteria of median sensory conduction block were a wrist to palm amplitude ratio of less than 0.61 and a wrist to palm duration ratio of less than 1.33. In the patient group, 10 hands (14.3%) showed motor conduction block and 12 hands (17.1%) showed sensory conduction block and 3 hands (4.3%) showed both. The wrist to palm amplitude ratios of CMAP and SNAP in the patient showing conduction block were 0.6⁑0.1, and 0.4⁑0.2, respectively. There was no correlation between palm CMAP or SNAP amplitude and respective wrist to palm ratios.

Conclusion: Comparison of the amplitude and duration of CMAP or SNAP obtained with stimulation of both wrist and palm may be able to differentiate between conduction block and axonal degeneration. These values may be useful in planning treatment and predicting outcome.

Objectives: To determine the effect of facilitation on H reflex side-to-side amplitude ratio and to determine the effect of averaging under the assumption that an averaging could further stabilize the amplitude ratio in a facilitated condition.

Method: FCR H reflex amplitude ratios of direct and averaged potentials were measured in fifty asymptomatic subjects under three conditions, during rest, during a constant 5 pound isometric contraction under the hand-dynamometer monitoring, and during a moderate constant isometric contraction under the electromyographer's verbal guidance.

Results: The lower limits of the amplitude ratios that encompass 97.5% of subjects by the percentile method under three conditions were as follows; (1) during the rest (n=37); 0.47 (direct) and 0.50 (average), (2) during the constant 5 pound isometric contraction under the hand- dynamometer monitoring; 0.47 (direct) and 0.48 (average), and (3) during the moderate constant isometric contraction under the electromyographer's verbal guidance; 0.48 (direct) and 0.46 (average), respectively.

Conclusion: There seems to be no definite effect of facilitation and averaging on H reflex amplitude ratio. H reflex amplitude ratio measured in facilitated condition without averaging is still useful for the diagnosis of unilateral radiculopathy.

The evaluation of peripheral nerve disorders has traditionally relied on clinical history, physical examination, and electrodiagnostic studies. The electrodiagnostic study is currently most popular procedure. The purpose of this study is to assess the significance of the changes of amplitude and area of compound muscle action potentials(CMAPs) in peripheral nerve injury. After compression of sciatic nerve in 65 Korean house rabbits, the amplitude and the area of CMAPs were compared to each other before and after compression injury.

The correlation coefficients between the changes of the parameters, amplitude and area, were obtained at a scheduled interval, and the parameters were also assessed when the evidence of denervation and regeneration was seen. In addition, the relationship between the degree of abonormal spontaneous activities and each parameter was assessed.

At preinjury state, there was a significantly high correlationship between two parameters. The correlation coefficients were 0.764 and 0.756 with distal and proximal stimulations respectively in abductor hallucis recordings, and 0.649 in gastrocnemius recording. At postinjury, there was more significant high correlationship between two parameters. The correlation coefficients were 0.955 and 0.962 with distal and proximal stimulations respectively in abductor hallucis recordings, and 0.930 in gastrocnemius recording. Nineteen cases showed denervation activities at postinjury 4th day. Of those cases, the amplitude was decreased earlier in 2 cases and the area in 3 cases at the same day. Of 10 cases regenerated, the amplitude was normalized earlier than the area in 2 cases. There was a significant decrement tendency in both amplitude and area with the degree of abnormal spontaneous activities.

Therefore, both the amplitude and the area of CMAPs are good quantitative indices of peripheral neuropathy and useful parameters in long-term follow up study.

Dysphagia is a disorder of the swallowing mechanism and presents a major problem in the rehabilitation of stroke patients. In the present study, computerized laryngeal analyzer (CLA) was used for noninvasive assessment of the pharyngeal phase of the swallowing mechanism. Laryngeal elevation was measured with pressor sensor placed on the skin over the thyroid cartilage. In the study, CLA was applied at each posture of neck flexion, neutral, and extension in stroke group and control group. Significant differences were found in each of these parameters measured in control group and stroke group. The quantitative measurements may aid the physician in choosing the appropriate therapy during the course of recovery.

The onset latency of swallowing was delayed in stroke group than control group at all posture of neck(p<0.05). The pharyngeal transit time (PTT) was longer at extension than flexion and neutral posture of neck in stroke group(p<0.05). The PTT was longer in stroke group than control group at all posture of neck, but not significant(p>0.05). The amplitude of swallowing was decreased in stroke group at extension and neutral posture of neck compared to those of control group(p<0.05), but there was no significant difference between stroke group and control group in neck flexion (p>0.05).