Normal Distal Motor Latency Research Articles

Electrophysiological variations of Guillain-Barre syndrome in Bangladesh- Hospital based study

Introduction: Guillain-Barre syndrome (GBS) is an immune mediated disorder of peripheral nerves which usually presents by rapidly evolving ascending weakness & mild sensory loss and hypo- or areflexia. Electrodiagnostic study (EDS) is the basis for classification of different subtypes of the disease. EDS also has a crucial role in diagnosis, ruling out of some differential diagnosis like myopathic and motor neuron disorders and confirming the neuropathic nature of GBS. The benefit of immunotherapy is greatest when introduced early. In addition, electrophysiological characteristic can predict the prognosis of patients with GBS. This study was conducted to determine the predominant subtype and electrophysiological pattern of GBS in the context of Bangladesh. Objectives: Objective of this study was to compare the electrophysiological variations among different electrophysiological subtypes of GBS. Methods: It is an observational cross sectional study conducted in Department of Medicine and Neurology, Sir Salimullah Medical College & Mitford Hospital and National Institute of Neuroscience (NINS), Dhaka, over a period of one year & four months. Total 30 patients were selected by purposive sampling technique. Demographic data were collected from the patients and recorded in structured case report form. Clinical examination and relevant investigations were done meticulously. Collected questionnaire were checked to identify any error in data. Data was analyzed with SPSS version 21 software. Result: In this study, maximum numbers of patients 53% were between 21-30 years of age group with mean value 27.47±8.1 years. Male to female ratio was 1.7:1. Frequency of Guillain-Barre syndrome is predominance at middle age group. Commonest presentation was limb weakness (parapledgia or quadripledgia) in 60% patients, paresthesias & numbness (40%), pain (100%) and deviation of mouth (63%) of GBS patients. Cerebrospinal fluid shows a mild pleocytosis (5 to 50 cells/µl) in majority of cases was found in 76% of patients. Whereas elevated CSF Protein (>45 mg/dl) was seen in all GBS patient. Increased distal motor latency (DML) was found in 93% patients, whereas 7% patients had normal DML. In the case of the lower limbs, increased distal motor latency was predominant. Decreased amplitude of sensory nerve action potential (SNAP) was seen in 83% patients while 16% patients had normal. Slowing of motor conduction velocities, decreased amplitude as well as increase in distal motor latencies were observed, being more pronounced in the lower limbs. F-wave was completely absent in 20.0% patients while 20% patients showed decreased conduction velocity with prolonged latency. Sensory nerve action potential revealed that decreased sensory conduction velocity (SCV) was seen in 26%, absent SCV in 10% and normal SCV in 63% patients. Present study demonstrated that Acute inflammatory demyelinating polyneuropathy (AIDP) was the commonest type of Guillain-Barré syndrome, present in 56% of patient. Around 30% of the patients belonged to acute motor axonal polyneuropathy (AMAN) and 13% were acute motor sensory axonal polyneuropathy (AMSAN). Conclusion: In this study AIDP was the most frequent subtype. The characteristic findings supportive of AIDP include prolonged distal motor latencies, reduced conduction velocities, conduction blocks at non-entrapment sites, temporal dispersion and prolonged F wave latencies. J MEDICINE 2024; 25: 11-16

When is needle examination of thenar muscle necessary in the evaluation of mild and moderate carpal tunnel syndrome?

Objectives This study aims to evaluate the predictors of standard nerve conduction study (NCS) parameters in determining the presence of axonal loss by means of spontaneous activity in patients with mild and moderate carpal tunnel syndrome (CTS). Patients and methods Between May 2015 and April 2018, a total of 118 patients (11 males, 107 females; mean age: 52.3±10.6 years; range, 27 to 79 years) who underwent electrophysiological studies and were diagnosed with CTS were included. Demographic data of the patients including age, sex, and symptom duration were recorded. Electrodiagnostic studies were performed in all patients. All the needle electromyography (EMG) findings were recorded, but only the presence or absence of spontaneous EMG activities was used as the indicator of axonal injury. Results In 37 (31.4%) of the patients, spontaneous activity was detected at the thenar muscle needle EMG. No spontaneous activity was observed in any of 43 (36.4%) patients with normal distal motor latency (DML). There were significant differences in DMLs, compound muscle action potential (CMAP) amplitudes, sensory nerve action potentials amplitudes, and sensory nerve conduction velocities between the groups with and without spontaneous activity (p<0.05). The multiple logistic regression analysis revealed that DML was a significant independent risk variable in determining presence of spontaneous activity. The most optimal cut-off value for median DML was calculated as 4.9 ms. If the median DML was >4.9 ms, the relative risk of finding spontaneous activity on thenar muscle needle EMG was 13.5 (95% CI: 3.6-51.2). Conclusion Distal motor latency is the main parameter for predicting the presence of spontaneous activity in mild and moderate CTS patients with normal CMAP. Performing needle EMG of the thenar muscle in CTS patients with a DML of >4.9 ms may be beneficial to detect axonal degeneration in early stages.

Guillain-Barr\xe9 syndrome following bacterial meningitis: a case report and literature review

BackgroundWe reported a case of an adult that presented Guillain-Barré syndrome (GBS) after bacterial meningitis which was secondary to chronic suppurative otitis media (CSOM). To our knowledge, this is the first case involving an adult presenting with GBS following bacterial meningitis.Case presentationA 46-year man with type 2 diabetes and otitis media (OM) suffered with fever, headache, and vomiting for 6 days. The patient’s neck stiffness was obvious and the Kernig and Brudzinski signs were produced. The result of cerebrospinal fluid (CSF) analysis and cytological examination of the CSF supported the diagnose of bacterial meningitis. On day 17 the patient felt numbness in both hands and feet, which gradually progressed to weakness of the limbs. Bladder dysfunction occurred, which required catheterization. The patient showed a tetraparesis with emphasis on the legs. The deep tendon reflexes of limbs were absent. The patient had peripheral hypalgesia and deep sensory dysfunction. The symptoms were possibly a result of GBS. Nerve conduction study showed that the F wave latency of the upper and lower limbs was prolonged, particularly the lower limbs. 8 days later the repeated nerve conduction study showed a low compound muscle action potential (3.3 mV) with a normal distal motor latency (14.2 ms) and a low motor nerve conduction velocity (34.3 m/s) in the tibial nerve. The patient still required assistance when walking 3 months after onset.ConclusionsGBS following bacterial meningitis is rare and limbs weakness in patients with bacterial meningitis was usually considered because of weakness. This case should serve as a reminder for clinical doctors that when a patient with bacterial meningitis complains about limbs numbness or weakness, GBS should be considered, especially when the patient had diabetes mellitus (DM) history.

Toward sensitive and specific electrodiagnostic techniques in early carpal tunnel syndrome

ContextThere remains no gold standard or even true agreement among clinicians as to which electrophysiological tests are most important and most relevant particularly in the mild and early carpal tunnel syndrome (CTS).AimThe aim of this study was to determine the sensitivity and specificity of electrodiagnostic (EDX) techniques to confirm the clinically diagnosed patients with mild CTS.Patients and methodsThis is a descriptive study. A total of 109 hands (68 right hands and 41 left hands) with symptoms consistent with mild idiopathic CTS, as well as 100 hands from controls, were clinically examined and underwent EDX evaluation.ResultsThe ring-difference and thumb-difference had the highest sensitivity, with the distal sensory latency (DSL) of the median nerve coming next. Combined sensory index (CSI) test at a cutoff point more than 1.1 had 100% specificity and positive predictive value. Abnormal DSL of the median nerve had the best negative predictive value. In patients with early and mild CTS and with normal distal motor latency and DSL, the CSI at cutoff point more than 1.1 is the best EDX test that is able to detect most of these patients.ConclusionCSI and its individual components appear as the best EDX tests that help in the diagnosis of patients with early and mild idiopathic CTS.

1-A-D-11. Electrodiagnosis for subtypes of Guillain–Barré syndrome: A single conduction study is not enough

Objective Current electrodiagnostic criteria for demyelinating and axonal forms of Guillain–Barre syndrome (GBS) may be incomplete. We evaluated serial changes in nerve conduction studies (NCSs) in GBS. Methods We reviewed NCS results on the first and second studies in 75 consecutive GBS patients. The patients were divided into two groups: anti-ganglioside antibody-positive and -negative (AGA-positive and -negative) groups. Results In the first study, 13 of 53 (25%) AGA-positive patients showed prolonged distal motor latency (DML) in the median nerve, whereas 5 of 22 (22%) AGA-negative patients had normal DMLs. In the second study, DMLs were shortened in the AGA-positive patients and significantly prolonged in the AGA-negative patients. Nine (17%) AGA-positive patients showed mildly prolonged DML in the median nerve, whereas 2 (9%) AGA-negative patients had normal DMLs. Most patients in the two groups did not show reduced motor conduction velocities (MCV) in the demyelinating range throughout the course. Interestingly, only few patients revealed prolonged F-waves in the demyelinating range. Conclusions To classify GBS into demyelinating and axonal forms, 2 sets of NCSs are required in which the median and ulnar but not tibial nerves are useful. Neither MCV nor F-wave is helpful for the classification.

Electrophysiological Assessment of Carpal Tunnel Syndrome in Elderly Patients: One-Year Follow-Up Study

To objectively assess elderly patients with carpal tunnel syndrome to characterize their preoperative severity and prognosis after carpal tunnel release using a electrophysiological severity scale. Electrophysiologic assessment was performed preoperatively and 1 year postoperatively following carpal tunnel release in 112 hands in patients over 70 years of age prospectively by the use of the following electrophysiological severity scale: stage 1, normal distal motor latency (DML) and normal sensory conduction velocity (SCV); stage 2, DML ≥ 4.5 milliseconds and normal SCV; stage 3, DML ≥ 4.5 milliseconds and SCV < 40.0 m/s; stage 4, DML ≥ 4.5 milliseconds and non-measurable SCV; stage 5; non-measurable DML and non-measurable SCV. Additionally, the outcomes of clinical symptoms of pain, nocturnal symptoms, numbness, loss of 2-point discrimination in the median nerve territory, and thenar atrophy were assessed. The mean age of patients was 77 years at the time of the operation. Preoperatively, the most common severity was stage 5 (70 of 112 hands, 63%), and clustering stage 4 and 5 together as severe resulted in 103 hands (92%). One year postoperatively, 97 hands (87%) demonstrated at least one stage improvement, and the numbers of mild (stage 1 or 2) increased from 3 (3%) to 45 hands (40%). Parallel with the electrophysiological improvement, pain and nocturnal symptoms resolved in 17 of 17 hands and 11 of 11 hands, respectively, in whom they were present preoperatively. Numbness, loss of 2-point discrimination, and thenar atrophy demonstrated the improvement in 96 of 112 (86%) hands, in 58 of 112 (52%) hands, and in 80 of 96 (83%) hands. We observed electrophysiologic improvement in 86% of elderly patients following carpal tunnel release. Electrophysiologic outcomes correlated with improvement in clinical variables. Therapeutic IV.

P605: Peroneal nerve damage after knee dislocation. Clinic, neurophysiology and ultrasound in diagnosis, prognosis, treatment and rehabilitation

P605: Peroneal nerve damage after knee dislocation. Clinic, neurophysiology and ultrasound in diagnosis, prognosis, treatment and rehabilitation

Delayed Electrophysiological Recovery After Carpal Tunnel Release for Advanced Carpal Tunnel Syndrome

Advanced carpal tunnel syndrome presents severe thenar atrophy with the absence of electrophysiological motor and sensory responses. Because of severity of these conditions, a substantial period of recovery after surgery is required before improvement becomes evident. In this electrophysiological-based study, the reappearance of distal motor latency (DML) at the abductor pollicis brevis and/or sensory nerve conduction velocity (SCV) after wrist stimulation were evaluated 1 year and 2 years after carpal tunnel release . To categorize outcomes, the following grading scale was used: stage I, normal DML and SCV; stage II, DML ≥ 4.5 ms and normal SCV; stage III, DML ≥ 4.5 ms and SCV < 40.0 ms; stage IV, DML ≥ 4.5 ms and nonmeasurable SCV; stage V: nonmeasurable DML and SCV. The authors found measurable DML and/or SCV and significant improvement both 1 year and 2 years postoperatively. Furthermore, the percentage of patients who recovered to the extent that they presented as mild carpal tunnel syndrome (stage I or II) increased significantly. They conclude that electrophysiological assessment of DML and SCV of advanced carpal tunnel syndrome using the above grading scale was effective as an objective evaluation tool of recovery after carpal tunnel release.

Neurophysiological classification and sensitivity in 500 carpal tunnel syndrome hands.

To evaluate the following points about carpal tunnel syndrome (CTS): 1) characterization of a wide population; 2) sensitivity of electrodiagnostic tests, and particularly the contribution of disto-proximal ratio test; 3) validity of a neurophysiological classification developed by us. Prospective study in 500 hands with CTS symptoms. Neurophysiological "standard" tests were always performed: sensory nerve conduction velocity (SNCV) first- and third digit-wrist and distal motor latency (DML). In "standard negative" hands disto-proximal ratio technique (R) was performed. Neurophysiological classification: Extreme CTS (absence of median motor, sensory responses), Severe (absence of sensory response, abnormal DML), Moderate (abnormal SNCV, abnormal DML), Mild (abnormal SNCV, normal DML), Minimal (abnormal R or other segmental/comparative test, normal standard tests). Sensibility of standard tests: 77%. R increased the diagnostic yield by 20%. CTS classification appeared reliable with significant differences between groups. R is a useful test, the classification may be useful in clinical/therapeutical decisions.

An electrophysiological severity scale in tarsal tunnel syndrome.

To propose a neurophysiological classification of tarsal tunnel syndrome. We retrospectively reviewed the medical records of two electromyography laboratories. Case inclusion criteria were based on clinical parameters. Motor conduction velocity, distal motor latency (DML), sensory conduction velocity (SCV) and sensory action potential (SAP) from big toe (T1) and from fifth toe (T5) to medial malleolus were measured in the medial and plantar nerves. When SCVs of T1 and T5 were normal, we considered the difference in T1 SCV between affected and unaffected side and in T1 SCV of the affected side with sural nerve distal SCV. Feet with TTS were classified in six electrophysiological classes: 0, normal SCV and DML; 1, normal absolute SCV with abnormal comparative tests; 2, slowing of T1 and T5 SCV and normal DML; 3, slowing of SCV and DML; 4, absence of T1 and T5 SAPs and abnormal DML; 5, absence of sensory and motor response. A total of 111 feet belonging to 96 patients (27 men, 69 women; mean age 49.6 years) were diagnosed with TTS. T1 and T5 SCV were abnormal in 82 and 73% of cases, respectively, and comparative tests were abnormal in a further 7% of cases. DML was abnormal in 82 feet (73.9%). Eight feet (7%) were without neurographic abnormalities. The distribution of feet in neurophysiological classes was: stage 0, 7%; stage 1, 9%; stage 2, 10%; stage 3, 39%; stage 4, 32%; stage 5, 3%. Higher clinical scores coincided with higher neurographic classes. The progression of neurographic abnormalities in TTS reflects the relation between SCV and DML, and between neurographic values and clinical severity. The scale assigns severity classes in a reliable and non-arbitrary way. This classification can easily be used by electrophysiological laboratories with their own electrophysiological techniques and normal values.

Electromyographic evaluation after endoscopic carpal tunnel release in idiopathic carpal tunnel syndrome

The purpose of this study was to electromyographically evaluate results in patients with carpal tunnel syndrome (CTS) who underwent endoscopic carpal tunnel release (ECTR). The subjects were 26 patients with idiopathic CTS (37 hands) who were followed for at least 6 months after ECTR. To compare results informatively, hands were classified into four groups: those with normal distal motor latency (DML) and sensory conduction velocity (SCV) were classified as group A, those with normal DML and abnormal SCV as group B, those with an abnormal DML and normal SCV as group C, and those with abnormal DML and SCV as group D. All but one of the hands were classified as group D on the basis of preoperative electromyographic evaluation, while one was classified as group C. The mean preoperative obtainable DML and SCV values were 7.2m and 27.3m/s, respectively. Postoperatively, 12 hands were in group A, 8 hands in group B, 2 hands in group C, and 15 hands in group D. The mean DML and SCV values at final follow-up were 4.3ms and 40.8m/s, respectively. Of the 25 hands with muscle atrophy before surgery, 6 hands were in group A, 5 hands were in group B, 1 hand was in group C, and 13 hands were in group D at final follow-up. Thenar muscle atrophy and denervation potentials were present before surgery in 13 of the 15 hands classified as group D at the final follow-up.

Surgical prognosis in carpal tunnel syndrome: usefulness of a preoperative neurophysiological assessment.

In this study 37 CTS hands underwent pre- and post-operative (15 days 2 and 6 months) evaluation of median nerve distal motor latency (DML) and sensory nerve conduction velocities (SNCV: I digit and III digit-wrist). Pre-operatively, CTS hands were classified as mild (decreased SNCV, normal DML), moderate (decreased SNCV, increased DML) or severe (absent sensory nerve action potentials, increased DML). Post-operatively, all hands presented clinical and neurophysiological improvement. The three groups of patient showed different clinical and neurophysiological responses to nerve decompression: we observed a rapid restitutio ad integrum in mild group, an improvement with normalisation in about 50% of the hands in moderate group, and a high percentage of restore of the sensory responses with no normalisation in severe group. A marked improvement of sensory symptoms was observed in all cases, but some degree of motor and/or sensory deficit was still present six months after surgery in more advanced cases. Preoperative electrophysiological assessment of median nerve function in CTS hands have an important role in predicting the outcome of surgical decompression.

Comparison of digital sensory studies in patients with carpal tunnel syndrome

Electrodiagnosis of carpal tunnel syndrome (CTS) often depends on the demonstration of focal slowing of median sensory fibers across the wrist. We compared the relative sensitivity of the four median innervated digits in demonstrating focal slowing in patients with CTS. Antidromic sensory studies of digits 1, 2, 3, and 4 were performed on 30 control subjects to develop normative data. Fifty-nine consecutive patients with CTS were then studied to determine the sensitivity of focal slowing of each median innervated digit. In the 26 CTS patients with a normal distal motor latency (DML) to abductor pollicis brevis, digit 1 was abnormal in 81%, digit 2 in 42%, digit 3 in 54%, and digit 4 in 38%. In the 33 CTS patients with a prolonged DML, digit 1 was abnormal in 94%, digit 2 in 88%, digit 3 in 91%, and digit 4 in 88%. We conclude that in milder cases of CTS with a normal DML, digit 1 is the most sensitive in identifying focal slowing of sensory conduction across the wrist. However, in patients with a prolonged DML, the sensitivity of sensory conduction is not significantly different among the four digits.

Carpal tunnel syndrome in patients on long-term hemodialysis.

Sixteen cases with carpal tunnel syndrome (CTS) were reported out of 412 patients on long-term hemodialysis due to chronic renal failure. Clinical symptoms included numbness in the area innervated by the median nerve in 100% of symptomatic hands and pain in the wrist and hand in 81%. This pain usually became severer at night and during hemodialysis. Muscle atrophy was noted in 41% of the hands. Nerve conduction studies revealed prolonged distal sensory latency, slowed sensory nerve conduction velocity across the wrist and normal distal motor latency in 18%, prolonged distal motor latency in 51% and no response in motor or sensory stimulation in 31%. Evidence of denervation on electromyography was seen in 36% of the hands. Patients were conservatively treated avoiding daily activities precipitating the condition with volar wrist splint only at night in 18% and in 90% with steroid hormone injection in the carpal tunnel. Median nerve release was performed in 18% of the hands. Amyloid deposit was demonstrated in 3 of 4 operated hands. Although the relation between long-term hemodialysis and the occurrence of the amyloid deposition in the carpal tunnel has not been established, the present data along with other recent reports strongly indicate that amyloid deposit in the carpal tunnel on hemodialysis patients could be one of the most possible cause of CTS.