Carpal tunnel syndrome: reappraisal of five clinical tests.

A combination of 5 clinical tests: Tinel (9, 10), Phalen (wrist flexion) (1, 2, 17), reverse Phalen (wrist extension) (4), carpal compression (11, 18), vibration (13, 14) was used in 74 hands with symptoms of carpal tunnel syndrome and proved by median sensory conduction velocity and distal latency across wrist and compared with 58 normal hands. Tinel test was the most specific and the least sensitive, vibration test was the most sensitive and the least specific. Carpal compression test was less sensitive and specific compared to Durkan's study. There was no correlation between Phalen time, reverse Phalen time, carpal compression time, and nerve conduction measurements. Cases with positive Tinel and vibration tests has slower sensory nerve conduction velocity (SNCV) compared to cases with negative results. Also patients with positive vibration tests had longer duration of symptoms in comparison to patients with negative test results. Up to now electrodiagnostic studies are the standard in diagnosing carpal tunnel syndrome and determining severity of median nerve involvement at wrist.

Fibrillation potentials and positive sharp waves in patients with antecedent paralytic poliomyelitis.

The diagnosis of post-polio syndrome depends not only on clinical signs, but on sophisticated laboratory tests such as histochemical muscle biopsy and immunohistochemical studies which are very expensive and not available in all laboratories. From eighty-eight previous poliomyelitis victims, muscles with grade 4 or lower strength were examined electromyographically for fibrillation potentials and positive sharp waves. There were no muscles with grade III or IV fibrillation potential and positive sharp waves, 8 with grade I (3.7%) and 7 with grade II (3.2%). Fibrillation potentials were more frequent in muscles with lower grade of strength. The minimum time interval between primary insult and the time of evaluation for patients who had sign of denervation was 36 months. This was 28 months for patients who had no sign of denervation. So we can conclude that denervation beyond this time in muscles with power greater than 3/5 is highly suggestive of a new process rather than primary insult in patients with new atrophy or fatigue.

The central loop of H-reflex in the S1 spinal nerve: normal values and constitutional influencing factors.

OBJECTIVE: To investigate the central loop of H reflex in the S1 nerve and the constitutional influencing factors in normal healthy individuals. MATERIALS AND METHODS: The study was performed on 39 apparently healthy volunteers. To obtain central H-reflex, the cathode electrode was inserted at a point 1 cm medial to the posterior superior iliac spine, perpendicular to the frontal plane. After the needle touched the sacrum, it was slightly retracted to avoid direct contract to the sacrum. The anode electrode was placed over the anterior iliac spine. The active pick-up electrode was placed at the middle of the line connecting the popliteal crease to the medial malleolus. The reference electrode was placed 2 cm distal to it. The ground eletrode was placed near the active pick-up electrode over the calf muscles. RESULTS: Mean +/- SD for minimum necessary stimulation to obtain central H-reflex was 23 +/- 13 mA. This was significantly higher than the minimum necessary stimulation to obtain peripheral H reflex (p < 0.0001 using paired t test). Mean central loop of H reflex was 6.9 msec with SD of 0.4 msec. There were no significant differences between the two sides. Mean amplitude of M-wave was 2.2 mV with SD of 1.5 in central loop study. Mean amplitude of H-wave was 2.4 mV with SD of 1.5 in central loop study. The Mean time interval between the onset of M-wave and the end of H-wave (M-H duration) was 18.5 msec with SD of 2.3. After stepwise reduction of variables, considering the correlation between leg length and other variables, the leg length was the only variable strongly correlating with central loop of H-reflex. CONCLUSION: Lack of major influencing factors after correction for leg length, elimination of a major fraction of the afferent segment of the loop, and its ability to differentiate peripheral from central lesions make central H-reflex studies an invaluable diagnostic tool.

Median-radial sensory latencies comparison as a new test in carpal tunnel syndrome.

Median and radial distal sensory latencies (DSL) were compared in 50 patients with carpal tunnel syndrome (CTS) and 50 healthy subjects by stimulating each nerve separately and recording sensory nerve action potential (SNAP) from standard anatomical locations for stimulation and recording sites. The range of difference between median DSL and radial DSL was 0.18 -1.18 msec in control group and 1.12-4.46 msec in CTS patients with a mean of 0.69 msec and 1.99 msec respectively (P < or = 0.0001). We found the value of 1 msec as a good cut-off point for diagnosis of CTS. The test described here seems to be an effective and simple criteria for increasing the sensitivity of nerve conduction studies in CTS.

A study of the sympathetic skin response and sensory nerve action potential after median and ulnar nerve repair.

The purpose of this study was to compare SSR with sensory nerve action potential (SNAP) responses in regeneration of injured peripheral nerves after nerve repair. We studied 10 male patients with a mean age of 26.7 years. All the patients had complete laceration of median or ulnar nerves. The patients were followed up at least for six months. SSR and SNAP assessment were performed every one to two months. Normal hands were used as controls. SSR was positive after 15.8 +/- 9.4 weeks (mean +/- 2 SD) and SNAP after 27.8 +/- 12.9 weeks (mean +/- 2 SD). The difference was statistically significant (P value < 0.001). This can be due to more rapid growth of sympathetic unmyelinated fibers relative to sensory myelinated fibers. This study also shows that recovery of the sudomotor activity following nerve repair is satisfactory in general and SSR can be used as a useful and sensitive method in the evaluation of sudomotor nerve regeneration.

Normal values of F wave in lower extremities of 73 healthy individuals in Iran.

F wave latency has been shown to be a simple and valuable method in evaluation of proximal part of peripheral nerves. According to our previous study of F wave of upper extremity nerves (1), maximum normal F wave latency for the median nerve was 28 ms with stimulation at wrist and 25 ms with stimulation at elbow. These values for the ulnar nerve were 29 ms and 25 ms respectively. Maximum normal difference between right and left F wave latency with wrist stimulation was 2 ms for median nerve and 2.5 ms for ulnar nerve. Maximum normal difference between median and ulnar nerve F latency was 3.5 ms with stimulation at wrist. In this study we measured F wave of lower extremity nerves in 73 healthy individuals in Shiraz. Maximum normal F wave latency for tibial nerve was 55 ms with stimulation at ankle and 46 ms with stimulation at popliteal area. Maximum normal F wave latency for the peroneal nerve was 54 ms with stimulation at ankle and 47 ms with stimulation at fibular head. Mean F ratio for both nerves was 1.29 with stimulation at knee. Maximum normal difference in F wave latency between right and left lower extremities was 3.5 ms with stimulation at ankle and 3 ms with stimulation at knee for the peroneal nerve. These values were 3 ms and 2.5 ms for the tibial nerve respectively. Maximum normal difference in F wave latency between tibial and peroneal nerve was 4 ms with stimulation at ankle and 3 ms with stimulation at knee.

Normal values of F wave in upper extremities of 50 healthy individuals in Iran.

F wave latency has been shown to be a valuable method in evaluation of a variety of neurologic disorders. We measured F wave values in 50 healthy individuals in Shiraz. Maximum normal F wave latency for median nerve was 25.7 ms for women and 28.5 ms for men with stimulation at the wrist. It was 23 ms for women and 25 ms for men with stimulation at the elbow. Maximum normal F wave latency for ulnar nerve was 26.45 ms for women and 28.9 ms for men with stimulation at the wrist. It was 23.1 ms for women and 25.3 ms for men with stimulation at the elbow. Maximum normal difference in F wave latency between right and left upper extremities with stimulation at the wrist for total group was 2.2 ms for median nerve and 2.4 ms for ulnar nerve. Maximum normal difference in F wave latency between median and ulnar nerve in an extremity with stimulation at the wrist for total group was 2.7 ms. There was statistically significant difference in F wave latency between women and men.

Value of sympathetic skin response in multiple sclerosis.

Thirty patients with definite multiple sclerosis along with fourteen healthy volunteers as control group were studied. Mean SSR latencies in the control group was 1,467 ms for upper extremities and 1,915 ms for lower extremities while 1,655 and 2,170 ms respectively in the patients with multiple sclerosis. Mean SSR amplitudes in the control group was 2.22 mV for upper extremities and 1.21 mV for lower extremities while 1.24 and 0.64 mV respectively in the patients with multiple sclerosis. All the differences between the patients and the control group was significant using T test (P = 0.001). Using Roc-curve, limits with highest sensitivity specificity products for SSR latency were calculated to be 1,700 ms for upper and 2,400 ms for lower extremities. For SSR amplitude they were 1.2 mV for upper and 0.5 mV for lower extremities. Considering absent SSR and/or at least 3 abnormal amplitudes or latencies as the criteria of abnormality, the specificity of the test was 100% and the sensitivity was 80% among our patients. Using the following criteria for abnormality, SSR study in the patients with multiple sclerosis is a test with high specificity and sensitivity: 1--Absent SSR, and/or 2--At least 3 abnormal out of the eight recordings (amplitudes and latencies of four extremities) with normal limits for SSR latency being defined as < or = 1,700 ms for upper and < or = 2,400 ms for lower extremities and for SSR amplitude as > or = 1.2 mV for upper and > or = 0.5 mV for lower extremities.

Meralgia paresthetica as the presenting feature of chronic appendicitis.

Meralgia paresthetica is an entrapment syndrome of the lateral cutaneous nerve of the thigh manifesting as paresthesia, pain, numbness, or sensory loss in the distribution of the nerve. A variety of causes have been described; however, the etiology often remains unknown. On the basis of our investigations with a patient with meralgia paresthetica, we determined that an inflammatory rather than mechanical effect on the lateral cutaneous nerve of the thigh may account for the pathogenesis; however, a certain conclusion about this issue can not be made.