Impaired transcallosal function in Amyotrophic Lateral Sclerosis

Objective: Identification of upper motor neuron (UMN) involvement is essential for the diagnosis of amyotrophic lateral sclerosis (ALS). Transcranial magnetic stimulation (TMS) has been shown to be useful to assess subclinical UMN involvement. In ALS mirror movements (MM) suggest an involvement of transcallosal fibre tracts associated with UMN involvement. The present study deals with the question of whether the analysis of transcallosal inhibition (TI) tested by TMS allows detection of cortical affection in ALS, even in early stages of the disease. Methods: In 17 patients with suspected ALS (12 male, 5 female,…