Uses
The number of motor units per muscle can change due to aging, disease, or injury. These techniques are used to diagnose disease or monitor the effects of aging, disease and injury over time. In neuropathies, motoneurons die off, reducing the number of motor units progressively. In myopathies the size of the motor units is reduced because of the death of motor fibres, but the number of motor units remains the same until the disease progresses to a very severe state. In collaboration with other electromyography techniques, these conditions can be diagnosed and monitored. In a similar vein, normal aging also reduces the number of motor units but not to the same degree as disease. The effects of injury depend on the circumstances.
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