The Awaji Commission recently proposed a modification of the electrodiagnostic 
criteria for ALS. We assessed whether the Awaji recommendations improve the 
sensitivity of the early diagnosis of ALS. In a retrospective study we reviewed 
clinical and neurophysiological data for 213 patients who visited our motor 
neuron disease outpatient clinic between October 2006 and December 2008. Using 
the El Escorial criteria, 51 patients were diagnosed with definite or probable 
ALS, 14 with probable laboratory-supported ALS, and 28 with possible ALS. An 
alternative diagnosis was present in 120 patients. Applying the Awaji 
recommendations, 66 patients were diagnosed with either definite or probable 
ALS, and 27 with possible ALS. Of the 14 patients diagnosed with probable 
laboratory-supported ALS, eight switched to probable ALS and six to possible ALS 
using the Awaji recommendations; none of the patients with an ALS mimic was 
diagnosed with ALS according to the Awaji recommendations. In conclusion, the 
new criteria for ALS do not result in a loss of specificity and can potentially 
improve the sensitivity by 16%. However, this diagnostic improvement appears 
eliminated if patients with probable laboratory-supported ALS - due to UMN signs 
in one region - should be categorized as possible ALS.