João Costa

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.

Neurophysiological techniques to detect early small-fiber dysfunction in transthyretin amyloid polyneuropathy

Introduction: Transthyretin familial amyloid polyneuropathy (TTR‐FAP) is characterized by early selective involvement of small nerve fibers. Initial clinical diagnosis is complicated by psychosocial factors. We evaluated diagnostic accuracy of sural sensory nerve action potentials, plantar sympathetic skin response (SSR), and cortical laser‐evoked potentials (LEP) to dorsal foot stimulation in the early diagnosis of TTR‐FAP.Methods: Sixty‐three subjects with TTR‐FAP (Val30Met) mutation were split into 2 groups (asymptomatic carriers and early‐symptomatic patients) and compared with 33 healthy controls. Results: The diagnostic accuracy of plantar SSR amplitude and LEP N2 latency was similar; all had very high specificity (94 to 97%) but low sensitivity (22 to 32%) in distinguishing controls from carriers and early‐symptomatic patients. No control had abnormal results on both tests. Conclusions: Plantar SSR and LEPs have similar diagnostic performance in detecting small‐fiber dysfunction in early TTR‐FAP; we propose that both tests should be used to investigate this population. Muscle Nerve 49: 181–186, 2014

The cost and burden of schizophrenia in Portugal in 2015

Católica Lisbon School of Business and Economics, Universidade Católica Portuguesa, Lisbon, Portugal Centro de Estudos de Medicina Baseada na Evidência, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal Centro Hospitalar de Lisboa Central, EPE, Lisbon, Portugal Laboratório de Farmacologia Clínica e Terapêutica, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal