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Mamede de Carvalho

Publications and source records attributed to Mamede de Carvalho.

28 records · Page 2Linked to original sources
PubMed2004

The Neurophysiological Index in ALS.

The Neurophysiological Index (NI) consists of a mathematical derivation of three standardised neurophysiological measurements. Since these measurements are part of routine practice in any clinical neurophysiology laboratory, calculation of the NI is within the capability of any laboratory. The NI is derived from the CMAP, the DML and the F-wave frequency (CMAP amplitude/DML) x F frequency %), representing aspects of the effects of denervation and reinnervation, of degeneration of the terminal part of the motor axons, and of the excitability of anterior horn cells. We have shown that this simple index is reproducible in consecutive studies of normal subjects and of patients with ALS (intra-rater reliability), and is sensitive to change. In ALS, the NI differentiates rapidly and slowly progressive disease at least as sensitively as other measures in common use, including the ALS-FRS. We propose that the NI could be used as a sensitive measure of change during the course of ALS and its treatment. In combination with relevant measures of clinical benefit, such as ALS-FRS and a QoL measure, this could simplify trial design and allow more rapid determination of the efficacy of putative new therapies in clinical trials.

Amyotrophic Lateral Sclerosis↗
PubMed2003

Motor responses evoked by transcranial magnetic stimulation and peripheral nerve stimulation in the ulnar innervation in amyotrophic lateral sclerosis: the effect of upper and lower motor neuron lesion.

We studied the upper (UMN) and lower motor neuron (LMN) innervations of 159 hands from 81 patients with amyotrophic lateral sclerosis (ALS). Eleven patients with various chronic LMN disorders causing weakness in the abductor digiti minimi (ADM) muscle served as LMN controls. Thirty healthy subjects served as normal controls. Cortical motor threshold, central conduction time (CMCT), and motor-evoked response amplitude (MEP) after transcranial magnetic stimulation (TMS) were studied, and the MEP/M wave ratio was calculated. The data was analyzed in the ALS subjects in groups defined by ADM muscle strength and by the presence or absence of clinical signs of UMN involvement. CMCT was not increased in the ALS or LMN disease groups. The threshold was higher in limbs with both weak ADM muscles and UMN signs. The MEP/M wave amplitude ratio was increased in weak muscles in the ALS patients, notably in limbs with no UMN signs, and also in weak muscles in patients with other chronic LMN disorders. It was frequently decreased in strong muscles. There was no difference between bulbar-onset and limb-onset ALS groups, and there was no correlation between threshold and disease duration. We suggest that expressing the data as an index and utilising the MEP/M wave amplitude ratio as a variable is a sensitive method for detecting UMN abnormality in ALS in particular in early affected muscles.

Adult↗
PubMed2003

Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis.

There is a need for a sensitive neurophysiological measure of disease progression in following the course of patients with amyotrophic lateral sclerosis (ALS). We studied two groups of nine ALS patients, one with slow progression (Group A) and the other with rapid progression (Group B). We evaluated muscle strength scores using the Medical Research Council (MRC) scale in limb and trunk muscles, forced vital capacity (FVC), and ALS functional rating scale (ALS-FRS) scores. Maximal voluntary isometric contraction (MVIC) of the abductor digiti minimi muscle (ADM) was measured, using a digital device. We also measured M-wave amplitude and area in the ADM, and the distal motor latency and F-wave frequency in the ulnar nerve; from these data, the neurophysiological index (NI) was calculated, as described previously. In both groups, the NI was the most sensitive measure of change, with the smallest coefficient of variation. We conclude that the NI, which requires no special technology and no new clinical or technical skills to use, is sensitive to change, and therefore may be useful in clinical trials, as well as in a clinical setting.

Adolescent↗
PubMed2003

Nocturnal pulse oximetry: a new approach to establish the appropriate time for non-invasive ventilation in ALS patients.

Previous studies have supported non-invasive ventilation (NIV) in amyotrophic lateral sclerosis (ALS), indicating that it prolongs survival. However, criteria for the use of NIV are yet to be defined. The aim of the present study was to evaluate the potential use of nocturnal pulse oximetry (NPO) as a tool for determining the most appropriate time at which to initiate NIV in ALS patients. We conducted a prospective, comparative, historical-controlled clinical study of 64 consecutive ALS patients. Group 1 (historical control group) comprised 44 patients, 14 women and 30 men, with a mean age of 60+/-13 years, in whom we used NIV after detecting early signs of diurnal respiratory insufficiency (RI). Group 2 had 20 ALS patients, 8 women and 12 men, with a mean age of 56+/-11 years, for whom we started NIV after detecting more than 15 periods of nocturnal desaturation/hour by NPO. All patients were periodically evaluated with Norris spinal and bulbar scores, respiratory function tests (RFT) and NPO at three month intervals for one year. They were subsequently followed until death or loss of autonomy from the ventilator. We compared survival time or time to loss of autonomy from the ventilator between both groups. Survival was longer in Group 2 (p<0.002). We concluded that NPO is a valuable screening test to establish the need for NIV. Our results also suggest that the early diagnosis of RI and the early use of NIV increase patient compliance with NIV.

Amyotrophic Lateral Sclerosis↗
PubMed2003

Clinical and therapeutic implications of presymptomatic gene testing for familial amyloidotic polyneuropathy (FAP).

Presymptomatic gene testing for familial amyloidotic polyneuropathies (FAP) is integrated in genetic counseling protocols common to other "Later onset, hereditary, autosomal dominant, no cure diseases" namely Huntington's Disease (HD) and Machado-Joseph disease (MJD). However, presymptomatic gene testing has specific clinical and therapeutic implications for FAP. Moreover, at least in Portugal, FAP ATTR Val30Met is a serious health problem. The most important implications are: the possibility of family planning including prenatal and preimplantation diagnosis; treatment with liver transplantation (TX); clinical follow-up according to protocols for early diagnosis which will allow patients to access therapy in useful time. This concept of useful time in FAP treatment is discussed. The growing possibilities of different therapeutic approaches are considered. In conclusion, presymptomatic gene testing for FAP may have a positive impact on candidate quality and prolongation of life, and on the future of disease studies.

Amyloid Neuropathies, Familial↗
PubMed2002

The corticomotor threshold is not dependent on disease duration in amyotrophic lateral sclerosis (ALS).

INTRODUCTION: It is suggested that early in ALS the corticomotor threshold (CMT) is low, but increases with increasing duration of the disease. POPULATION AND METHODS: We compared CMT, central conduction time and motor-evoked response/M-wave amplitude in two populations of ALS patients: one with disease duration shorter than 6 months (Group A, 11 patients) and another who had had the disease for more than 24 months (Group B, 14 patients). These two groups were compared with a control group of 30 subjects. In all the ALS patients, abductor digiti minimi (ADM) strength was greater than MRC 3. RESULTS: M-wave amplitude was comparable in the three groups. We found no difference between the three groups in these transcranial magnetic stimulation studies and there was no correlation between disease duration time and CMT. CONCLUSION: We did not confirm a relation between CMT and disease duration. An increased CMT late in the disease progression is associated with greater lower motor neuron loss, and greater corticospinal tract degeneration with dispersion of the descending motor volley.

Adult↗
PubMed2002

F-Waves and the corticospinal lesion in amyotrophic lateral sclerosis.

INTRODUCTION: In upper motor neuron (UMN) syndromes, F-waves are of higher amplitude, increased duration, and increased latency. Increased F-wave frequency in UMN syndromes is not well documented. We have studied the effect of corticospinal lesion on F-wave frequency, M-wave amplitude, distal motor latency and on the Neurophysiological Index (CMAP amplitude/DML x % F-wave frequency) which we have described previously in amyotrophic lateral sclerosis (ALS). METHOD: We studied 145 abductor digiti minimi (ADM) muscles in 75 patients with ALS. Six groups of hands were defined, based on strength of the ADM, as assessed clinically by the MRC scale, and the presence or absence of UMN signs in the same upper limb. RESULTS: CMAP amplitude and area were decreased, and DML increased, in weaker muscles (MRC < 3) causing a change in the ALS Neurophysiological Index. In general, UMN signs were not correlated with increased F-wave frequency. In five weak hands F-responses were studied in individual motor units. A larger number of responding motor units in these weak limbs with UMN signs was observed. CONCLUSION: F-wave excitability is largely dependent on the size of the lower motor neuron pool.

Action Potentials↗
PubMed2002

Long-term quantitative evaluation of liver transplantation in familial amyloid polyneuropathy (Portuguese V30M).

Familial amyloid polyneuropathy (FAP) is associated with massive endoneurial and extracellular deposition of amyloid, which isformed from a mutated transthyretin (TTR) protein. Ninety percent of TTR protein is produced in liver. Liver transplantation (LT) is the only treatment that can halt FAP clinical progression. We studied 35 LT patients. The mean age of the first symptoms was 36.6 years (ranging from 27 to 56), 19 were males, and 16 females, they underwent LT after a mean time of 5 years of symptomatic disease. Fifteen patients followed for more than 24 months after LT had periodic evaluations with clinical and neurophysiological scores (CS and NS). Ten were first evaluated before LT (mean follow-up time of 44 months after LT), and 5 were evaluated only after LT (or a mean time of 41 months). Five patients were followed periodically before LT (mean time of 44 months) to study the natural course of this condition. The mortality rate was of 14% in the first 6 months and was related to known complications of the surgery. No deaths occurred in the period 6 months to 1 year after LT. Five patients (14%) died 1-2 years after LT, 4 of whom were transplanted in advance stages. In the survival group, CS tended to stabilize shortly after LT and to remain invariable later on. The NSprogressed in the first year following LT, and subsequently it did not increase significantly. LT changed the natural course of FAP-I.

Adult↗