P344 Motor cortical excitability changes in early stage ALS patients using automatic threshold tracking method

Abstract

Objectives to determine motor cortical excitability changes in early stage ALS patients. Methods Twenty-seven ALS patients were recruited the study. The mean age was 55.2 years and seven patients were female. Cortical excitability tests performed on the diagnostic stage of the disease. Investigated cortical excitability parameters were; resting motor threshold: (RMT), short interval intracortical inhibition (SICI), short interval intracortical facilitation (SICF) and intracortical facilitation (ICF). Results Mean RMT was 60.1 ± 2.2% MSO for ALS patients, 52.9 ± 3.1% for control group. There was not significant difference between two groups ( p > 0.05 ). Factor analysis of SICI resulted in two factors with eigenvalues more than 1. In the calculation of factor 1 (SICI1-2.5 ms) values, short ISI values have more weight than long ISI values. The opposite was true for factor 2. (SICI2.5-5 ms). Mean SICI1-2.5 msvalues were 11.3 ± 11.7 in ALS group and 74.3 ± 9.9 in control group ( p 0.05 ) while mean SICI2.5-5 ms were 10.6 ± 9.7 in ALS group and 67.8 ± 9.8 in control group ( p 0.05 ). Factor analysis of SICF and ICF resulted in two factor with eigenvalues more than 1. There were no significant difference between two groups any of these two factors both for SICF and ICF ( p > 0.05 ). Comment SICI values are significantly reduced in ALS patients at the early stage of the disease. Significance SICI analysis with automatic threshold tracking method may have potential role for diagnosis of ALS. Reliability and reproducibility of this test should be performed before using it as a diagnostic test.