Diagnosis of<unk>  can be difficult, since the symptoms are hard to separate from complications due to the original<unk>  infection, and from the normal infirmities of aging. No laboratory test for<unk>  is known, nor are any other specific diagnostic criteria. Three important criteria are recognized, including previous diagnosis of<unk> , long interval after recovery, and gradual onset of weakness. In general,<unk>  is a diagnosis of exclusion whereby other possible causes of the symptoms are eliminated. Neurological examination aided by other laboratory studies can help to determine what component of a neuromuscular deficit occurred with<unk>  and what components are new and to exclude all other possible diagnoses. Objective assessment of muscle strength in<unk>  patients may not be easy. Changes in muscle strength are determined in specific muscle groups using various muscle scales that quantify strength, such as the Medical Research Council (MRC) scale. magnetic resonance imaging, neuroimaging, and electrophysiological studies, muscle biopsies, or spinal fluid analysis may also be useful in establishing a<unk>  diagnosis.
Post-polio syndrome
Leukomyelitis
Guillain–Barré syndrome
FACES syndrome
Acute disseminated encephalomyelitis
Eastern equine encephalitis
Tension myositis syndrome
Postvaccinal encephalitis