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Normal volitional control of movement depends on the balanced relationship of the cortical, subcortical, cerebellar, spinal, and peripheral nervous systems. Neurologic dysfunction can result from compromise at any point in this balance resulting in motor or sensory impairment, or both. This chapter reviews essential features of common diseases encountered in neurorehabilitation, including amyotrophic lateral sclerosis, Guillain-Barré syndrome, polio and post-polio syndrome, and Parkinson’s disease, with a focus on diagnosis, treatment, and rehabilitation for each disorder.



  • Most widely known motor neuron disease.

  • Insidious onset and rapidly progressive course.

  • Most common presentation is painless asymmetric limb weakness and atrophy.

  • Diagnosis is primarily clinical, based on the presence of upper and lower motor neuron signs.

General Considerations

In its classic form, amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease affecting both upper and lower motor neurons that results in destruction of the anterior horn cells, motor cranial nerve nuclei, and corticospinal–bulbar tracts. Patients most commonly present with painless asymmetric limb weakness, but other symptoms associated with upper and lower motor neuron degeneration include spasticity, pathologic reflexes, and muscular atrophy. The worldwide prevalence is 5–7 in 100,000, and men are more commonly affected than women at a ratio of 1.5:1.0. The disease onset is typically between 40 and 60 years of age (mean: 58 years).

A group of atypical motor neuron diseases has been studied that usually but do not always evolve into ALS. These disorders—progressive muscular atrophy (PMA), progressive lateral sclerosis (PLS), and progressive bulbar palsy (PBP)—are distinct but interrelated disorders, perhaps representing variants within a spectrum of ALS disease.

A. Progressive Muscular Atrophy

PMA is a sporadic disease affecting only the anterior horn cells without involvement of the upper motor neurons (UMNs). Hence, those affected exhibit only lower motor neuron (LMN) signs. As such, the most common presenting symptom of PMA is distal limb weakness with muscle atrophy. The natural history of PMA and ALS demonstrate such a high degree of similarity as to often be indistinguishable, and in one study of PMA subjects, 35% of patients developed UMN signs, mirroring the classic ALS phenotype.

B. Progressive Lateral Sclerosis

PLS is also a rare sporadic motor neuron disorder. The initial manifestations of the disease are dominated by UMN features. The chief complaint is progressive asymmetric spasticity, most commonly in the legs followed by the arms or bulbar muscles. The disease progression appears to be slower than in ALS, occurring over years to decades. The life expectancy of patients with PLS is also better than that of ALS patients, ranging between 7 and 14 years. Ultimately, approximately 45% of PLS patients go on to develop LMN symptoms and progress to ALS.

C. Progressive Bulbar Palsy


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