American Association of Electrodiagnostic Medicine guidelines for outcome studies in electrodiagnostic medicine

OUP accepted manuscript

Spinocerebellar ataxias consist of a highly heterogeneous group of inherited movement disorders clinically characterized by progressive cerebellar ataxia variably associated with additional distinctive clinical signs. The genetic heterogeneity is evidenced by the myriad of associated genes and underlying genetic defects identified. In this study, we describe a new spinocerebellar ataxia subtype in nine members of a Spanish five-generation family from Menorca with affected individuals variably presenting with ataxia, nystagmus, dysarthria, polyneuropathy, pyramidal signs, cerebellar atrophy and distinctive cerebral demyelination. Affected individuals presented with horizontal and vertical gaze-evoked nystagmus and hyperreflexia as initial clinical signs, and a variable age of onset ranging from 12 to 60 years. Neurophysiological studies showed moderate axonal sensory polyneuropathy with altered sympathetic skin response predominantly in the lower limbs. We identified the c.1877C > T (p.Ser626Leu) pathogenic variant within the SAMD9L gene as the disease causative genetic defect with a significant log-odds score (Z_max = 3.43; θ = 0.00; P < 3.53 × 10⁻⁵). We demonstrate the mitochondrial location of human SAMD9L protein, and its decreased levels in patients’ fibroblasts in addition to mitochondrial perturbations. Furthermore, mutant SAMD9L in zebrafish impaired mobility and vestibular/sensory functions. This study describes a novel spinocerebellar ataxia subtype caused by SAMD9L mutation, SCA49, which triggers mitochondrial alterations pointing to a role of SAMD9L in neurological motor and sensory functions.

Ultrasound-guided perineural vs. peritendinous corticosteroid injections in carpal tunnel syndrome: a randomized controlled trial

BACKGROUND

Corticosteroid injections are proven to be effective in the management of carpal tunnel syndrome (CTS); however, the optimal injection site still remains unclear.

AIM

To compare the efficacy of perineural vs. peritendinous target sites for corticosteroid injection in CTS.

DESIGN

A Randomized, Single-Blind, Controlled Trial.

SETTING

Outpatients, tertiary care center.

POPULATION

Forty-six patients were equally randomized into two intervention groups as Group A (18 F and 5 M, mean age;50.0 ± 15.9 years, mean symptom duration;5.9 ± 3.3 months) and Group B (19 F, 4 M patients, mean age;54.3 ± 15.0 years, mean symptom duration;5.9 ± 4.7 months).

METHODS

Methylprednisolone acetate (40 mg) and 1 mL of 1% trimecaine hydrochloride was injected next to the median nerve (Group A) or among flexor tendons away from the nerve (Group B) under ultrasound (US) guidance. The visual analogue scale was used as the primary outcome measure, and the symptom severity scale and functional status scale of the Boston Carpal Tunnel Questionnaire were used as the secondary subjective outcome measures. Twopoint discrimination, grip strength, cross-sectional area, and distal motor latency were assessed as objective outcome measures. The data were collected at baseline and at 2, 6 and 12 weeks after the injection.

RESULTS

Both groups showed improvement in subjective and objective measures at 2 weeks following the injection - also maintained up to 12 weeks during the follow-up (p<0.05). However, no difference was observed between the two groups (p<0.05). No serious adverse effects were observed in either group.

CONCLUSIONS

Both intervention techniques seem to be effective and safe in the conservative treatment of CTS.

CLINICAL REHABILITATION IMPACT

Based on this study results, it might be noteworthy that physicians can opt for perineural or peritendinous injections without compromising the treatment efficacy and safety. Herewith, US guidance is, for sure, necessary for performing safe and accurate injections.

Diagnostic Accuracy of the Neck Tornado Test as a New Screening Test in Cervical Radiculopathy

BACKGROUND

The Spurling test, although a highly specific provocative test of the cervical spine in cervical radiculopathy (CR), has low to moderate sensitivity. Thus, we introduced the neck tornado test (NTT) to examine the neck and the cervical spine in CR.

OBJECTIVES

The aim of this study was to introduce a new provocative test, the NTT, and compare the diagnostic accuracy with a widely accepted provocative test, the Spurling test.

DESIGN

Retrospective study.

METHODS

Medical records of 135 subjects with neck pain (CR, n = 67; without CR, n = 68) who had undergone cervical spine magnetic resonance imaging and been referred to the pain clinic between September 2014 and August 2015 were reviewed. Both the Spurling test and NTT were performed in all patients by expert examiners. Sensitivity, specificity, and accuracy were compared for both the Spurling test and the NTT.

RESULTS

The sensitivity of the Spurling test and the NTT was 55.22% and 85.07% (P < 0.0001); specificity, 98.53% and 86.76% (P = 0.0026); accuracy, 77.04% and 85.93% (P = 0.0423), respectively.

CONCLUSIONS

The NTT is more sensitive with superior diagnostic accuracy for CR diagnosed by magnetic resonance imaging than the Spurling test.

Description of transthyretin S50A, S52P and G47A mutations in familial amyloidosis polyneuropathy

OBJECTIVE

To describe 58 subjects with rare TTR mutations, and to compare the different biomarkers between carriers and patients.

METHODS

TTR gene sequence test was performed in 15 suspicious subjects and in their direct family. All positive subjects undertook prospective evaluations in a period of 49 months.

RESULTS

Of 95 genetic tests performed, 58 (61%) were positive for TTR mutations, Ser50Arg mutation in 38 (65%), Ser52Pro in 15 (26%) and Gly47Ala in 5 (9%). Initial symptoms were neuropathic in 19 (73%), gastrointestinal in 6 (23%) and autonomic in 1 (4%).

CONCLUSIONS

The natural history of Ser50Arg, Ser52Pro and Gly47Ala TTR mutations is similar to the Val30Met mutation described in endemic areas. The small fiber assessments were the initial tests to show abnormalities in asymptomatic subjects.

Reversal of suprascapular neuropathy following arthroscopic repair of massive supraspinatus and infraspinatus rotator cuff tears

PURPOSE

The purpose of this study was to study the prevalence of suprascapular neuropathy (SSN) in the setting of massive rotator cuff tears and to determine if arthroscopic rotator cuff repair, even if partial, was associated with reversal of SSN and clinical improvement in pain and function.

METHODS

Over a 13-month period, 26 of 216 patients with rotator cuff tears treated operatively were identified to have massive tears associated with retraction and moderate to severe fatty infiltration of the supraspinatus and infraspinatus muscles. All patients had pain and marked weakness in abduction and external rotation which did not improve with conservative treatment. Electrodiagnostic electromyographic/nerve conduction velocity (EMG/NCV) evaluation, as well as pre- and postoperative questionnaire and physical examination, were performed. An arthroscopic repair, either partial or complete, was performed on patients identified to have a massive rotator cuff tear in association with SSN.

RESULTS

Fourteen of 26 patients with massive rotator cuff tears (54%) were identified to have a peripheral nerve injury. Seven of these 26 (38%) had isolated suprascapular nerve injury, 4 had axillary nerve injury, 2 had an associated upper trunk brachial plexus injury, and 1 had a cervical radiculopathy. All 7 patients with isolated suprascapular injury underwent arthroscopic treatment, 1 of which was not technically reparable at the time of surgery. In the 6 patients who underwent either partial or complete arthroscopic repair, follow-up EMG/NCV after 6 months demonstrated partial or full recovery of the suprascapular nerve palsy that correlated with complete pain relief and marked improvement in function.

CONCLUSIONS

SSN is found in a significant proportion of patients with massive rotator cuff tears, and is associated with pain and dysfunction. Arthroscopic rotator cuff repair can result in reversal of SSN, which may correlate with substantial improvement in pain and function.

LEVEL OF EVIDENCE

Level IV, case series.