Shoji Hemmi

Simple and novel method to measure distal sensory nerve conduction of the medial plantar nerve

A simple and reliable method for recording sensory nerve action potentials (SNAPs) of the medial plantar nerve is described. Medial plantar SNAPs were recorded by placing surface electrodes on the sole. Ring electrodes were used for orthodromic stimulation at the big toe. Sixty‐four healthy subjects ranging in age from 13 to 81 years were examined to establish normal values. Mean amplitude for the medial plantar SNAP was 4.7 ± 2.8 μV and mean maximum conduction velocity was 43.5 ± 6.4 m/s. The normal values for amplitude obtained for the medial plantar SNAPs were higher than those obtained by the method of Guiloff and Sherratt, and the sensitivity of our method for diagnosis of early sensory neuropathy was relatively higher. The method should therefore be useful in the diagnosis of early sensory neuropathy. Muscle Nerve, 2007

Muscular fatigue and decremental response to repetitive nerve stimulation in X-linked spinobulbar muscular atrophy

Background and Purpose:  We report decremental responses to repetitive nerve stimulation (RNS) in 11 patients diagnosed with X‐linked spinobulbar muscular atrophy (X‐SBMA).

Magnetic resonance imaging diagnosis of panniculitis in dermatomyositis

A 64-year-old woman noticed gradual weakness in her legs and difficulty in walking, followed by weakness in her arms and neck 4 months prior to admission. At the time of admission the patient was unable to get up from bed and was unable to lift her arms above her head. Abnormal neurological findings included MRC (Medical Research Council scale) strength of 2 in neck flexors, 3 in deltoids and biceps, 4 in hand grip, 3 in iliopsoas, and 4 in hamstrings and anterior tibialis muscles. She also had moderate atrophy in her upper arms and thighs. Erythematous rashes were noted over her arms, trunk, legs, and face. Multiple cutaneous ulcers of her elbows, wrists, and toes were first noticed 2 months after the onset of weakness. Laboratory findings included normal creatine kinase, mildly elevated aldolase, high sedimentation rate, and negative anti-Jo-1 antibody. An extensive cancer work-up was negative. Needle electromyography showed significant findings indicative of active myopathy. Magnetic resonance imaging (MRI) of the bilateral thighs showed marked enlargement of subcutaneous fat tissue (Fig. 1A,B). The subcutaneous fat showed a diffuse reticular pattern with low signal intensity on T1-weighted images (Fig. 1A). Short tau inversion recovery (STIR) images showed high signal intensity in regions with low signal intensity on T1-weighted images (Fig. 1B). These MRI findings suggested extreme subcutaneous edema and inflammation caused by panniculitis. Muscle biopsy from the left biceps brachii revealed perivascular lymphocytic inflammation and perifascicular muscle fiber atrophy consistent with a diagnosis of dermatomyositis (not shown). A subcutaneous fat biopsy specimen from the site of the muscle biopsy showed extensive lymphohistiocytic panniculitis (Fig. 1D). Once the diagnosis had been made, treatment with prednisolone at 40 mg/day was started. Immediately after the start of treatment, gradual improvement in the strength of her neck and proximal muscles was seen, and she was able to walk independently at the time of discharge. Follow-up T1-weighted images done 3 months after treatment showed normalized intensity and thickness in subcutaneous fat tissue (Fig. 1C). Cutaneous findings such as Gottron’s sign and heliotrope erythema in dermatomyositis are well known, but, clinically, subcutaneous involvement appears to be uncommon. Since the first report of panniculitis associated with dermatomyositis by Weber and Gray in 1924, only 20 cases have been reported in the literature. However, histological changes of panniculitis are more frequently observed in biopsy specimens from subcutaneous fat tissue. The incidence of these histological changes has been reported to be 3.4% by Solans et al. and 9.1% by Janis and Winkelmann. Fusade et al. considered that the discrepancy between frequencies of clinical manifestations and histological changes indicated a variable degree of severity of panniculitis. Since panniculitis is only found incidentally by biopsy in most cases, it may be an underreported finding in dermatomyositis. On the basis of clinical data in 21 panniculitis cases with dermatomyositis (our case and literature review), the sites of panniculitis were the thigh in 12 cases (57.1%), arm in 12 cases (57.1%), buttocks in 11 cases (52.4%), and abdomen in four cases (19.0%). Dates of diagnosis of panniculitis relative to the onset of dermatomyositis were antecedent in four cases (19.0%), concurrent in five cases (23.8%), and subsequent in 12 cases (57.1%). The most notable feature in our case was that MRI suggested the presence of panniculitis with dermatomyositis before biopsy from subcutaneous fat tissue. In addition, MRI was useful for assessing the effectiveness of treatment with a steroid for panniculitis. Tests should include MRI to search for signs of panniculitis, because nearly all dermatomyositis cases with panniculitis respond well to steroids, and good disease control is achieved with immunosuppressive therapy. VC 2009 Wiley Periodicals, Inc.

Diagnostic markers of axonal degeneration and demyelination in sensory nerve conduction

The aim of this study was to formulate diagnostic hallmarks of axonal degeneration and demyelination in sensory nerve conduction studies (NCS).

On-nerve needle nerve conduction study in the sural nerve: A new technique for evaluation of peripheral neuropathy

OBJECTIVE The objective of this study was to compare the nerve conduction study (NCS) data by the surface electrode (SE)-NCS versus the on-nerve needle (ONN)-NCS and to assess their clinical usefulness in the diagnosis of peripheral neuropathy. METHODS Sensory compound nerve action potentials (CNAPs) were obtained by the ONN-NCS with needle electrodes placed on the exposed sural nerve during biopsy in 94 patients with peripheral neuropathy. RESULTS The ONN-NCS is possible in 95% of cases. The ONN-NCS was able to record sensory CNAP in 15% of cases when it was unobtainable in the SE-NCS. The ONN-NCS showed higher amplitude and longer duration of the CNAP but a slower maximum nerve conduction velocity (NCV) than the SE-NCS. The ONN-NCS showed a significantly better concordance with the nerve biopsy findings, especially in demyelinating neuropathy. CONCLUSION The ONN-NCS is a better electrophysiological test for the histopathological correlation with nerve biopsy. SIGNIFICANCE The ONN-NCS was able to record sensory CNAP in 15% of cases when it was unobtainable in the SE-NCS.

INTRAOPERATIVE ON-NERVE NERVE CONDUCTION STUDY AND CONVERSION FACTOR IN THE SURAL NERVE

To determine the conversion factor (CF) of the sural nerve the correlation between the maximum nerve conduction velocity (NCV) and the diameter of the largest fibers was studied in 30 patients suspected of having neuropathy. Sensory nerve action potentials were obtained by on‐nerve needle nerve conduction study using needle electrodes placed on the exposed sural nerve during biopsy. The CF was 4.3 (n = 2) in normal sural nerves and close to the normal value (3.85, n = 4) in axonal neuropathy. The CF in demyelinating neuropathy was smaller than the normal value (2.77, n = 24), indicating disproportionately slower conduction than expected from the diameter of nerve fibers. The CF was helpful in differentiating between demyelinating and axonal neuropathies. We propose that a 36% decrease from the mean value of NCV is a reasonable criterion for demyelination of the nerve. Muscle Nerve, 2010

Tongue fasciculations in chronic inflammatory demyelinating polyradiculoneuropathy

nerve conduction study in normal subjects. Muscle Nerve 1995; 18:330–335. 2. Kumar N, Folger N, Bolton CF. Dyspnea as the predominant manifestation of bilateral phrenic neuropathy. Mayo Clin Proc 2004;79:1563–1565. 3. Lin PT, Andersson PB, Distad BJ, Barohn RJ, Cho SC, So YT, et al. Bilateral isolated phrenic neuropathy causing painless bilateral diaphragmatic paralysis. Neurology 2005;65:1499 – 1501. 4. Maher J, Grand’Maison F, Nicolle MW, Strong MJ, Bolton CF. Diagnostic difficulties in myasthenia gravis. Muscle Nerve 1998; 21:577–583. 5. Valls-Solé J, Solans M. Idiopathic bilateral diaphragmatic paralysis. Muscle Nerve 2002;25:619–623.

Variations in the distal branches of the superficial fibular sensory nerve

Introduction: We evaluated anatomic variations of distal branches of the superficial fibular sensory nerve electrophysiologically. Methods: Orthodromic nerve conduction studies (NCS) of the first and third branches (M‐I, M‐III) of the medial dorsal cutaneous nerve and the fourth and fifth branches (I‐IV, I‐V) of the intermediate dorsal cutaneous nerve (IDCN) were performed. To find anomalous innervations from the dorsal sural nerve (DSN) in the IDCN territory, NCS of the fourth and fifth branches (S‐IV, S‐V) of the DSN were also performed. Results: All sensory nerve action potentials (SNAPs) of M‐I and M‐III could be obtained bilaterally from 31 healthy Japanese volunteers. SNAPs of I‐IV and I‐V were recordable in 85.5% and 43.5% of feet, respectively. Anomalous innervations from the DSN were confirmed in 71.0% of S‐IV and 93.5% of S‐V. Conclusion: These results suggest that anatomical variations in the IDCN territory are very frequent in Japanese subjects. Muscle Nerve 55: 74–76, 2017

A NOVEL METHOD TO MEASURE SENSORY NERVE CONDUCTION OF THE SUPRACLAVICULAR NERVE

Introduction: In this report we describe a reliable method for recording sensory nerve action potentials (SNAPs) of the supraclavicular nerve. Methods: Supraclavicular SNAPs were recorded by placing a surface active electrode at the posterior border of the sternocleidomastoid muscle at a distance of 6 cm from the sternoclavicular joint. The nerve was stimulated at the lower border of the clavicle 4.5 cm lateral to the sternoclavicular joint. Results: Supraclavicular SNAPs were recorded bilaterally from 20 healthy volunteers. Mean onset latency was 1.0 ± 0.2 ms, and mean peak latency was 1.4 ± 0.3 ms. Mean baseline‐to‐peak amplitude for the SNAPs was 6.1 ± 2.2 µV, and mean maximum conduction velocity was 59.8 ± 6.2 m/s. The mean percentage of side‐to‐side difference in amplitude was 12.9 ± 11.0%. Conclusions: Supraclavicular SNAPs could be obtained in all normal subjects. Assessment of supraclavicular nerve conduction is very useful in the diagnosis of supraclavicular neuropathy Muscle Nerve 50: 1005–1007, 2014

Unilateral calf hypertrophy and focal myositis induced by S1 radiculopathy: dramatic response to steroid treatment

Unilateral enlargement of the calf in a 57-year-old man with S1 radiculopathy is described in this case report. Short tau inversion recovery-weighted imaging provided evidence of selective hypertrophy and a high signal intensity of the gastrocnemius and soleus. Histopathological analysis of the gastrocnemius revealed an endomysial inflammatory infiltrate and marked denervation lesions. Marked signs of denervation are suggestive of focal myositis secondary to neurogenic damage. The patient was treated with an oral corticosteroid (30 mg/day) and the calf hypertrophy was dramatically reduced within 5 weeks. Our case indicates that steroid therapy should be tried because it may be a potentially treatable disease.