Background: Recently, new electrophysiological ALS criteria incorporating fasciculation potentials (FPs) as evidence for lower motor neuron signs (Awaji Criteria (AC)) was proposed to provide earlier detection of early-stage ALS than revised El Escorial electrophysiological criteria (REEC). However, serial electrophysiological analysis is lacking to ascertain the original intention. The objective for this study was to elucidate whether electrophysiological criteria set for AC detects ALS earlier than REEC's counterpart in patients with ALS.
Methods: Of the 51 patients who were clinically suspected of ALS, 35 patients prospectively received serial electrophysiological studies every 3 months until (1) both electrophysiological AC and REEC criteria were met in more than two muscles representing both of the cervical and lumbosacral segments or (2) either clinically definite or clinically probable REEC criteria was met. The intervals were determined between the initial disease onset and when the respective electrophysiological criteria were met.
Results: Electrophysiological diagnostic criteria were met in 94.3% by AC and 40% by REEC at the initial visits. The intervals between the disease onset and the time of meeting the electrophysiological criteria were shorter in AC (mean: 9.0 months) than in REEC (mean: 15.2 months) (P<0.01). Eleven patients who met only AC electrophysiological criteria on the initial study subsequently met REEC electrophysiological criteria with the mean interval of 3.8 months. A higher percentage of bulbar-type ALS (83.3%) met AC than limb-onset ALS (43.4%) (P<0.05). FPs tended to be more frequently observed than fib/psw in the muscles outside the region of initial clinical onset.
Conclusion: Electrophysiological criteria of AC were met earlier than that of REEC in ALS patients, especially in patients with bulbar onset. Early recognition of ALS by AC may allow effective therapeutic intervention in the early disease stage.
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