A new technique for dorsal sural nerve conduction study with surface strip electrodes.

OBJECTIVE: To obtain higher amplitude of dorsal sural sensory nerve action potentials (SNAPs), we used a new method for dorsal sural nerve conduction study with surface strip electrodes (SSEs). METHODS: Dorsal sural SNAPs were recorded orthodromically. The recording electrodes were placed behind the lateral malleolus. SSEs were attached to the laterodorsal aspect of the foot for stimulation of the dorsal sural nerve (DSN). We also used a conventional method with a standard bipolar stimulator and compared the findings. RESULTS: Dorsal sural SNAPs were recordable bilaterally from 49 healthy volunteers. Mean peak-to-peak amplitude for SNAPs was 12.9±6.3µV, and mean nerve conduction velocity was 44.8±5.5m/s. The mean amplitude of SNAPs obtained by our method was 118.6% higher than that of SNAPs obtained by the conventional method (12.9µVvs. 5.9µV; P<0.001). CONCLUSIONS: The highest amplitude of dorsal sural SNAPs was constantly obtained by SSEs since SNAPs arising from whole digital branches of the DSN could be elicited by placement of SSEs. SIGNIFICANCE: When the DSN supplies more cutaneous branches to the lateral half of the foot, SSEs gives higher amplitude of dorsal sural SNAPs than that of the standard innervation type.

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.

[Early Detection of Manganese Intoxication Based on Occupational History and T1-weighted MRI].

Manganese regulates many enzymes and is essential for normal cell function. Chronic manganese intoxication has an insidious and progressive course terminating to atypical parkinsonism with little therapeutic efficacy. For subjects with chronic manganese exposure such as welders, manganese intoxication can be detected early based on the presence of hyperintensity in the globus pallidus on T(1)-weighted MRI and abnormally high urinary excretion of manganese with a chelating agent even in cases of normal serum/urine level of manganese.

Acute disseminated encephalomyelitis associated with oral polio vaccine.

A 27-year-old woman presented with acute paresis after taking an oral polio vaccine (OPV). Deep tendon reflexes were preserved, needle electromyography showed no neurogenic changes, and there were no lesions on spine magnetic resonance imaging (MRI), suggesting that motor neurons of the spinal cord were not affected. Brain MRI showed abnormal lesions in the tegmentum of the upper pons, left cerebral peduncles, truncus of the corpus callosum, and right parietal lobe. Cerebrospinal fluid revealed mild pleocytosis. The most probable diagnosis was acute disseminated encephalomyelitis associated with OPV.