Orofacial Apraxia in Motor Neuron Disease

Introduction: Cognitive and behavioral impairments are considered to occur frequently in amyotrophic lateral sclerosis/motor neuron disease (MND). Rarely, apraxia has been reported in MND. Orofacial, or buccofacial, apraxia is characterized by a loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles in the presence of preserved reflexive and automatic functions of the same muscles. Methods: We report a patient with MND who presented with spastic dysarthria and asymmetric orofacial apraxia. She progressed to frontotemporal dementia (FTD). Results: Clinical and neurophysiological examinations were suggestive of bulbar-onset MND-FTD. Tractography showed a reduction of fractional anisotropy in the centrum semiovale, corona radiata, corticomedullary pathway and inferior aspect of the medulla; the changes were more severe on the left side. To our knowledge, this is the first report of an asymmetric presentation of an apraxic syndrome in MND-FTD.