F-Waves and the corticospinal lesion in amyotrophic lateral sclerosis

Carvalho, Mamede de; Scotto, Manuel G.; Lopes, Arminda; Swash, Michael

doi:10.1080/146608202760834139

Cited by 29 publications

(25 citation statements)

References 17 publications

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“…8,20,21 F-wave persistence when compared with controls was abnormal in 23 patients with MND and decreased as MRC graded strength decreased. F-wave latencies and chronodispersion, defined as the difference between the maximal and minimal F-wave latencies, were increased in the ALS patients as compared to the controls in this study by Argyriou and colleagues.…”

Section: Peripheral Nerve Conduction Studies In Alsmentioning

confidence: 88%

Electrodiagnosis in Persons With Amyotrophic Lateral Sclerosis

Joyce

Carter

2013

PM&R

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Electrophysiology remains an important tool in the evaluation of patients presenting with signs and symptoms of motor neuron disease (MND). The electrodiagnostic study should include peripheral nerve conduction studies (NCS) and needle electromyography (EMG) to both exclude treatable disease and gather evidence toward a diagnosis of amyotrophic lateral sclerosis (ALS). The recent changes in the revised El Escorial criteria, recommended by the Awaji-shima consensus group, have increased the diagnostic significance of fasciculation potentials to equal that of fibrillation and positive sharp wave potentials in the needle EMG examination of the patient suspected of having ALS. In addition, electrophysiologic evidence is now considered equivalent to clinical signs and symptoms in reaching diagnostic certainty of ALS. These changes, strategies for the design and implementation of an effective electrodiagnostic evaluation, and additional electrophysiologic techniques and their relationship to the evaluation of a patient with ALS are reviewed and discussed.

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Section: Peripheral Nerve Conduction Studies In Alsmentioning

confidence: 88%

Electrodiagnosis in Persons With Amyotrophic Lateral Sclerosis

Joyce

Carter

2013

PM&R

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“…A reduction of F‐wave persistence associated with immobility has been described, although this has not been replicated by others . Upper motor neuron lesions are associated with a higher frequency and amplitude of F‐wave responses, as observed in amyotrophic lateral sclerosis . The effect of immobility on H‐reflex responses is less well studied.…”

Section: Introductionmentioning

confidence: 94%

Immobility and F‐waves: Impact on lower motor neuron excitability

Pereira¹,

Swash

Carvalho

2020

Muscle and Nerve

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Introduction Immobility of the upper limbs has been associated with reduction of F‐wave frequency. However, there are no similar studies on lower limb (LL) F‐waves. We investigated the impact of LL rest on F‐wave and H‐reflex parameters. Methods The LLs of 14 healthy participants were studied after 90 minutes rest. F‐waves (frequency, latencies, chronodispersion, and mean amplitude) and H‐reflexes (latency and recruitment curve) were investigated bilaterally. In seven participants the protocol was repeated, but the temperature of one limb was reduced. Results Immobility only changed F‐wave latencies, which increased significantly (mean value of 2 ms, P < .01). Limb cooling did not influence results. Discussion Contrary to what occurred in cervical lower motor neurons (LMN), LL LMNs did not show a reduced F‐wave response to immobility, but their latency increased significantly. This could have been due to reduced Renshaw inhibition of small LMNs, thus facilitating their response to antidromic stimulation and causing delayed late responses.

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“…The F‐wave minimal latency was determined from recordings following 20 consecutive supramaximal stimuli at 1 H Z . A peak‐to‐peak deflection from baseline of at least 40 μV was accepted as an F wave 8, 10. At the first investigation, standard ulnar nerve conduction studies were performed below and across the elbow to exclude ulnar nerve entrapment.…”

Section: Methodsmentioning

confidence: 99%

“…In a previous study in ALS patients, we observed significant positive correlations between strength of the abductor digiti minimi muscle (ADM) and a number of neurophysiological parameters, particularly compound muscle action potential (CMAP) amplitude and area, and F‐wave frequency; in addition, a negative correlation was found with distal motor latency (DML) 8. From these data, we calculated the neurophysiological index (NI), according to the formula: (CMAP amplitude/DML) × F frequency % 8, 10. This index proved to be strongly correlated with strength 8, 10…”

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confidence: 99%

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Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis

Carvalho

Scotto

Lopes³

et al. 2003

Muscle and Nerve

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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.

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F-Waves and the corticospinal lesion in amyotrophic lateral sclerosis

Abstract: F-wave excitability is largely dependent on the size of the lower motor neuron pool.

Cited by 29 publications

References 17 publications

Electrodiagnosis in Persons With Amyotrophic Lateral Sclerosis

Electrodiagnosis in Persons With Amyotrophic Lateral Sclerosis

Immobility and F‐waves: Impact on lower motor neuron excitability

Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis

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