Confounding effects of mimicking disorders in the early diagnosis of amyotrophic lateral sclerosis.

A diagnosis of amyotrophic lateral sclerosis (ALS) should be given to the patient only when the doctor or the neurologist feels confident or certain about the diagnosis. Certainty of a diagnosis of ALS is important because there are a number of disorders that could mimic the symptoms of ALS but differ in prognosis and treatment. Early treatment of ALS is critical to offer optimal therapy to the patient. However, ALS is difficult to diagnose at an early stage. The fact that ALS is a rare disease means doctors and neurologists do not always have the necessary experience to diagnose confidently. Therefore, clear strategies involving criteria for clinical evaluation and ancillary tests such as electromyography, muscle biopsy and magnetic resonance imaging, must be set up to establish the presence of upper and lower motor neuron abnormalities.