[Electromyography in atypical variants of motor neuron disease: a case series].

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both the upper and lower motor neurons, it has a heterogeneous clinical presentation, there are atypical variants that differ from the classic form of the disease. The criteria for diagnosis have evolved over time, with the support of electromyography (EMG), we present a patient series with these variants in which EMG was crucial to make the diagnosis. Clinical cases: Six cases are described with atypical presentation of motor neuron disease, for the isolated bulbar ALS phenotype, three cases are reported: two male patients (68 and 62 years old) and one woman (33 years old), with initial symptoms in the bulbar segment and late progression. to a second segment, corroborating characteristic findings by EMG. For the variant of Vulpian-Bernhardt syndrome (VBS), two male patients aged 82 and 72 years are reported, with initial symptoms in the thoracic segment with electromyographic support for the diagnosis; Finally, a case of amyotrophic diplegia of the legs (APD) is described in a 50-year-old female patient with symptoms isolated to the pelvic limbs, with a slow clinical evolution, corroborated by EMG with involvement of other spinal segments. Conclusions: ALS a spectrum of motor neuron disease, a neurodegenerative disease of the CNS, without curative treatment and one with a fatal outcome, the diagnosis of ELA is complex and becomes more complex for atypical phenotypes, as observed in the presented cases EMG is an essential part of the approach and part of the diagnostic criteria.