The flail-arm syndrome: the influence of phenotypic features.

Objective: The flail-arm syndrome (FAS), one of the Amyotrophic lateral sclerosis (ALS) phenotypes, is characterized by slow progression and predominantly lower motor neuron (LMN) involvement with proximal upper limb (UL) weakness. We aim to characterize the clinical features, progression and survival of FAS associated with distal or proximal onset and presence or absence of upper motor neuron signs (UMN) signs at diagnosis. Methods: Data from 704 ALS patients was analyzed. Of the 190 patients with UL onset; 134 were excluded as not respecting the published criteria for FAS. The included patients were divided into four groups according to distal/proximal onset and presence/absence of UMN signs. Results: 56 FAS patients (8% of the population), median age at onset 59.9 years (Q1/Q3, 50.3-68.1), 75% men, were studied. Distal onset with UMN signs occurred in 37.5%, distal onset without UMN signs in 28.6%, proximal onset with UMN signs in 8.9% and proximal onset without UMN signs in 25%. Age of onset, sex, fasciculations at onset, diagnostic delay, progression rate, time to respiratory involvement and survival were similar among the four groups. Sex ratio was more balanced in patients with UMN signs (p = 0.032) and survival was shorter (69.5 months, 95% CI: 55.4-110.4 vs 152.6 months, 95% CI: 69.0-177.3; p = 0.035). The Cox regression identified rate of progression (p < 0.001) and UMN signs (p = 0.003) as independent predictors of shorter survival. Conclusions: Distal or proximal onset had no influence on clinical characteristics and prognosis but UMN signs at diagnosis are a negative prognostic predictor.

Breathing new life into treatment advances for respiratory failure in amyotrophic lateral sclerosis patients.

In the last three decades, improvements in respiratory management are responsible for increasing survival and improving quality of life for amyotrophic lateral sclerosis (ALS) patients. Nowadays, ALS patients with respiratory involvement are offered a support treatment other than the traditional respiratory palliative care. Knowledge about available respiratory support potentialities is essential for appropriate, customized and effective treatment of ALS, which should probably be started sooner than the conventional approach. There is evidence supporting that respiratory support has a larger impact than riluzole on survival. Noninvasive ventilation is essential in the treatment of ALS patients with respiratory involvement. In this article methods to determine respiratory failure in ALS, mechanical invasive and noninvasive ventilation, telemetry, diaphragm pacing, cough aids and respiratory exercise are reviewed, after a brief overlook of respiratory insufficiency in ALS.

Impact of medical audit on electrodiagnostic medicine in polyneuropathy.

OBJECTIVE: The aim of the study was to investigate whether experienced physicians' electrodiagnostic practice and criteria can be influenced by international collaboration involving peer review medical audit. METHODS: Data was obtained from the ESTEEM project, an ongoing collaboration since 1991 among European neurophysiologists concerned with quality improvement in electrodiagnostic medicine. Three sets of the physicians' polyneuropathy examinations performed with intervals of 2-4 years were analysed. RESULTS: Changes towards increased homogeneity among the physicians were found in (1) the average number of studies performed per patient and the number of abnormal studies required for accepting the diagnosis of polyneuropathy, with the most pronounced changes seen for abnormal motor nerve segments, abnormal F-wave studies, and electromyographic studies, and (2) the agreement on pathophysiological interpretation of nerve conduction studies and classification of polyneuropathy. CONCLUSIONS: Changes towards increased homogeneity contributed to years of participation in peer review medical audit, were seen among a group of experienced physicians. Peer review medical audit as carried out here is however difficult to scale up. Therefore guidelines or minimal criteria should ideally supplement a medical audit process to disseminate the results obtained to a larger audience. SIGNIFICANCE: These results support the role of international peer review medical audit in quality improvement of electrodiagnostic medicine.

Motor Unit Number Index (MUNIX): a novel neurophysiological marker for neuromuscular disorders; test-retest reliability in healthy volunteers.

OBJECTIVE: To investigate the intra-rater and inter-rater test-retest reliability of the Motor Unit Number Index (MUNIX) in healthy subjects in a multicentre setting. METHODS: Six study centres applied the MUNIX technique in 66 healthy subjects. Five to six muscles (biceps brachii, BB; abductor digiti minimi, ADM; abductor pollicis brevis, APB; tibialis anterior, TA; extensor digitorum brevis, EDB and abductor hallucis, AH) were measured in each volunteer four times by two independent examiners. RESULTS: The method was easy to perform and well tolerated. The intraclass correlation coefficient (ICC) varied between centres and muscles. Intra-rater reliability was greatest for the AH (ICC 0.83) and EDB (ICC 0.81). Inter-rater reliability was greatest for the AH (ICC 0.69) and ADM muscles (ICC 0.69). The most critical muscle was the APB muscle (ICC 0.52, total variability). This was mostly due to variability in the compound muscle action potential (CMAP) measurements. MUNIX values of the APB, ADM and TA fell into the same range as in other motor unit number estimation (MUNE) studies. CONCLUSION: MUNIX measurements in multiple muscles show good inter- and intra-rater reliability in healthy subjects. CMAP amplitude must be controlled to optimize reliability. SIGNIFICANCE: Results suggest that MUNIX could serve as a reliable marker for motor neuron loss in diseases like amyotrophic lateral sclerosis.

Awaji diagnostic algorithm increases sensitivity of El Escorial criteria for ALS diagnosis.

We have tested the sensitivity of a recently published approach to combining clinical and EMG data in the 'research diagnosis' of ALS, in 55 consecutive patients clinically diagnosed with ALS. The application of this 'Awaji algorithm' to the revised El Escorial diagnostic criteria for diagnosis of ALS achieved a diagnostic sensitivity of 95% for definite ALS compared with 18% using the clinical El Escorial criteria and 53% when the EMG criteria as defined in the El Escorial criteria, were applied to the same dataset. This increased sensitivity was particularly relevant for bulbar onset patients (sensitivity improved from 38% to 87%) and for patients with El Escorial clinically possible ALS (from 50% to 86%). We suggest that, in future, investigators and triallists should use the Awaji algorithm superimposed onto the El Escorial criteria, in selecting patients for research studies.