ALS Diagnootic Criteria

EMG's decreased recruitment, unstable MUPs, fasciculations, fibrillation potentials, polyphasiscs, increased amplitude and duration. NCS show low amplitude CMAPs which are related to disease severity and prognosis. Ulnar stimulation at Erb's point is necessary to look for conduction block. EMG muscle selection should be done to minimize sticks. Need to see decreased recruitment large MUPs and fibs in at least three levels. Thoracic paraspinals are typically abnormal (80 % quoted) and are useful if coexisting cervical paraspinal abnormalities are seen. EL Escorial Criteria (replaces prior Lambert criteria which were more stringent). There are 4 body regions: bulbar, cervical, thoracic and lumbar. Definite ALS requires denervation in 3 of 4 levels; probable, 2 levels, possible 1 level; suspected 2 levels without UMN signs. In each level, at least two muscles of different spinal nerve, and peripheral nerve innervation should be tested.