Abstract: ObjectiveTo explore the factors that delayed the diagnostic process and resulted in misdiagnosis of amyotrophic lateral sclerosis (ALS),in order to look for solution. MethodsThe records of 99 cases with ALS from 1999 to 2003 in our hospital were reviewed retrospectively. Clinical characteristics and diagnostic process on the patients were statistically analyzed.ResultsThe time needed to confirm diagnosis was (13.1±7.5) months. There was a positive correlation between the time when EMG was performed and the time the diagnosis was made. 58.6% of patients were initially misdiagnosed in other hospitals. The most common misdiagnosis was cervical spondylosis. The misdiagnosis more likely occured in the patients of 40-59 years old. The misdiagnosis rate in the patients with initial lower extremities symptoms was higher than that with initial bulbar and upper extremities symptoms. The misdiagnosis more likely occured in patients with early cervical MRI.ConclusionThe major causes of misdiagnosis are unfamiliarity of the physician with the disease,misleading findings or misinterpretation of neuro-radiological or neuro-physiological findings.

Key words: amyotrophic lateral sclerosis, early diagnosis, misdiagnosis