Since 1988 when multifocal motor neuropathy (MMN) was first described as a distinct neurological entity, numerous attempts to classify its exact nature have been proposed.
Currently the following ten criteria are generally accepted as clinical presentations for multifocal motor neuropathy.
- Slow or stepwise progressive limb weakness
- Asymmetrical limb weakness
- Fewer than 7 affected limb regions (upper/lower arm, upper/lower leg on both sides)
- Tendon reflexes in affected limbs are decreased or absent
- Signs and symptoms are more pronounced in arms than in legs
- Age 20-65 years at onset of disease
- No objective sensory abnormalities except for vibration sense
- No bulbar signs or symptoms
- No upper motor neuron features
- No other neuropathies
Along with laboratory and electro-diagnostic testing, a qualified professional can make a tentative diagnosis if the patient does indeed have multifocal motor neuropathy.
As the preferred treatment options for this rare, but debilitating disease are different from other conditions which closely mimic MMN, a definitive diagnosis is essential for successful treatment to begin.
Since multifocal motor neuropathy does not have a fatal prognosis, early detection can lead to arresting its effects for a limited time, although as yet a full cure is not possible.