What does fibrillation mean on EMG?

Fibrillation potentials are the most common abnormal spontaneous discharges recorded during needle EMG. Fibrillation potentials represent the action potentials of single muscle fibers that fire spontaneously in the absence of innervation (Buchthal and Rosenfalck, 1966; Goodgold and Eberstein, 1967).

What does abnormal EMG sound like?

The sound of positive sharp waves have been described as, like ‘claps of distant thunder’, and fibrillation potentials a higher pitched and shorter duration sound, like ‘rain on a tin roof’.

What is the difference between fasciculations and fibrillations?

Fibrillation and fasciculation both show up on EMGs, but fibrillations show a very very tiny electrical impulse, whereas a fasciculation would show a very large impulse.

What are fibrillation potentials?

Introduction. Rhythmic fibrillation potentials are the hallmark of denervated muscle fibres in needle EMG of a striated muscle (Conrad et al. 1972, Heckmann & Ludin 1982). They are readily activated by the insertion of an EMG needle electrode (Kugelberg & Petersén 1949).

How are fibrillation potentials recorded in the muscle?

Fibrillation potentials may be triggered by mechanical stimulation of a muscle fiber from the needle electrode; however, the recording of fibrillation potentials using subcutaneous electrodes without needle compression of the muscle supports their spontaneous occurrence (Buchthal and Rosenfalck, 1966 ).

When to expect positive wave fibrillation in neurogenic disorders?

In early studies, it was suggested that positive sharp wave fibrillation potentials were encountered more frequently in neurogenic than myopathic disorders ( Goodgold and Eberstein, 1967 ). Additionally, positive wave fibrillation potentials might be encountered earlier after injury to a nerve than spike form fibrillation potentials.

How is fibrillation recorded on a monopolar needle?

Fibrillation is the name given to spontaneous activity recorded by a monopolar or concentric needle inserted into a muscle belly while the muscle is at rest.

What can an electromyography ( EMG ) tell you about your body?

Statistics from Altmetric.com. Electromyography (EMG), the recording of electrical activity in muscle, should be regarded as an extension of the clinical examination. It can distinguish myopathic from neurogenic muscle wasting and weakness. It can detect abnormalities such as chronic denervation or fasciculations in clinically normal muscle.