Detecting fasciculations in amyotrophic lateral sclerosis: duration of observation required

Mills, Kerry

doi:10.1136/jnnp.2009.186833

Cited by 55 publications

(48 citation statements)

References 13 publications

(14 reference statements)

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“…We have demonstrated that such a localized event, even at the distal end of the axon, can trigger hyper-excitability and generate ectopic APs. This phenomenon is reminiscent of fasciculation potentials, an early clinical hallmark of the disease (Mills, 2011), reflecting spontaneous discharges of single motor units. The origin of fasciculation potentials has been a source of intense debate since the early work of Denny-Brown and Pennybacker (1938).…”

Section: Discussionmentioning

confidence: 99%

A Computational Model of Motor Neuron Degeneration

Masson

Przedborski

Abbott

2014

Neuron

139

163

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SUMMARY To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations.

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Section: Discussionmentioning

confidence: 99%

A Computational Model of Motor Neuron Degeneration

Masson

Przedborski

Abbott

2014

Neuron

139

163

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“…The conventional EMG method for fasciculation detection requires recording with a concentric needle EMG electrode from several locations, each for at least 90 s to be sure that fasciculations are or are not present 53. Fasciculation potentials should be searched for in several upper limb and lower limb muscles and also, when clinically relevant, in the genioglossus, although in the latter it is difficult to achieve full relaxation during needle EMG examination.…”

Section: Methods For Detecting Fasciculationsmentioning

confidence: 99%

Fasciculation in amyotrophic lateral sclerosis: origin and pathophysiological relevance

Carvalho

Kiernan

Swash

2017

J Neurol Neurosurg Psychiatry

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This review considers the origin and significance of fasciculations in neurological practice, with an emphasis on fasciculations in amyotrophic lateral sclerosis (ALS), and in benign fasciculation syndromes. Fasciculation represents a brief spontaneous contraction that affects a small number of muscle fibres, causing a flicker of movement under the skin. While an understanding of the role of fasciculation in ALS remains incomplete, fasciculations derive from ectopic activity generated in the motor system. A proximal origin seems likely to contribute to the generation of fasciculation in the early stages of ALS, while distal sites of origin become more prominent later in the disease, associated with distal motor axonal sprouting as part of the reinnervation response that develops secondary to loss of motor neurons. Fasciculations are distinct from the recurrent trains of axonal firing described in neuromyotonia. Fasciculation without weakness, muscle atrophy or increased tendon reflexes suggests a benign fasciculation syndrome, even when of sudden onset. Regardless of origin, fasciculations often present as the initial abnormality in ALS, an early harbinger of dysfunction and aberrant firing of motor neurons.

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“…We identified FPs only when potentials of the same shape appeared at least twice. To detect FPs, we observed spontaneous activity at one site in each muscle for 60–90 s, which is sufficiently long enough to confirm the reproducibility of FPs 29. Any persistence of voluntary MUPs was considered to render the identification of FPs impossible.…”

Section: Methodsmentioning

confidence: 99%