Nerve conduction studies through landmark based recording and effects of hand length.

As per existing guidelines, the distance between stimulator and recording electrodes in nerve conduction studies (NCS) should be the same (fixed) in all the subjects, i.e., it should not be based on anatomical landmarks. However, there are no studies comparing fixed distance recordings with landmark based NCS. We postulated that hand length can influence the NCS parameters in fixed distance recordings and this can be nullified using landmark based recordings. To test this theory, we performed NCS in 48 normal subjects as per standard guidelines (standard protocol) and then compared it to NCS with ulnar styloid as the landmark (modified protocol). NCS were performed on median and ulnar nerves of the right upper limb. Three motor NCS parameters including distal latency, compound muscle action potential (CMAP) amplitudes and nerve conduction velocities were measured. Sensory nerve action potential (SNAP) amplitudes and conduction velocities were the two sensory parameters measured. On analysis, ulnar motor conduction velocity was the only parameter affected by hand length in both standard and modified protocols. Modified protocol did not have any additional advantage to the standard protocol advised by NDTF. We conclude that the NDTF guidelines are therefore reasonable when considering the effects of hand length. Possible reasons for this result including anatomical and anthropometric explanations are discussed.

Spectrum of Acute Neuropathy Associated With Covid-19: A Clinical and Electrophysiological Study of 13 Patients From a Single Center.

OBJECTIVES: To analyze clinical and nerve conduction patterns in patients with acute neuropathy, preceded by or concomitantly having Covid-19 disease (Acute neuropathy associated with Covid-19 or ANAC 19). METHODS: A retrospective analysis of clinical details, laboratory evaluation and electrophysiological parameters in patients with ANAC 19 was performed. These data were compared with non-Covid Guillain-Barre syndrome (GBS) described in literature and also with patients with acute neuropathy without Covid-19 who had presented to the center during the study period. RESULTS: Records of 13 patients with ANAC 19 were reviewed. Most patients clinically had paraparesis, and electrophysiologically showed demyelinating neuropathy. Peroneal and sural nerves were the most frequently abnormal motor and sensory nerves, respectively. A proportion of patients showed a peroneal velocity-sparing pattern. Higher incidence of paraparesis and encephalopathy differentiated ANAC 19 from non-Covid GBS. CONCLUSIONS: ANAC 19 had a comparable electrophysiological profile to non-Covid GBS; however, it had a distinct clinical presentation.

Sleep profile and Polysomnography in patients with drug-resistant temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) and the effect of epilepsy surgery on sleep-a prospective cohort study.

OBJECTIVES: We analyzed changes in sleep profile and architecture of patients with drug-resistant TLE-HS using three validated sleep questionnaires- Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), NIMHANS Comprehensive Sleep Disorders, and polysomnography (PSG). We studied the effect of epilepsy surgery in a subset of patients. METHODS: In this prospective observational cohort study, sleep profile of 40 patients with drug-resistant TLE-HS was compared to 40 healthy matched controls. Sleep architecture of 22 patients was studied by overnight PSG and compared to 22 matched controls. Sleep profile was reassessed in 20 patients after a minimum period of three months after epilepsy surgery. RESULTS: The mean PSQI was higher among patients compared to controls(P=0.0004) while mean ESS showed no difference. NCSDQ showed fewer patients feeling refreshed after a night's sleep compared to controls (p=0.006). PSG revealed a higher time in bed (p=0.0001), longer total sleep time (p=0.006) and more time spent in NREM stage 1 (p=0.001) and stage 2 (p=0.005) while spending less time in stage 3 (p=0.039) among TLE patients. Sleep efficiency was worse in patients on ≥3 ASMs compared to those on 2 ASMs (p-0.044). There was no change in mean ESS (p=0.48) or PSQI (p=0.105) after surgery. CONCLUSIONS: Patients with drug-resistant TLE-HS have an altered sleep profile and architecture. Patients on ≥3 ASMs have a lower sleep efficiency. Reassessment at short intervals after epilepsy surgery did not reveal significant changes in sleep profile.