Changes in the excitability of anterior horn cells in a mental rotation task of body parts.

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.

Esclerosis Lateral Amiotrófica, presentación atípica / Atypical presentation of Amyotrophic lateral sclerosis

La esclerosis lateral amiotrófica (ELA) es una enfermedad neurodegenerativa, progresiva, con desenlace fatal, que afecta a neuronas motoras de la médula espinal, tronco cerebral y corteza motora. Se produce un fracaso del sistema motor que dirige, regula y mantiene la musculatura esquelética, responsable de la capacidad para moverse y relacionarse con el entorno. Presentamos el caso de un hombre de 58 años de edad con diagnóstico de ELA, con sintomatología inicial atípica que dificultó el juicio clínico final, resaltando en el diagnóstico diferencial la miopatía por cuerpos de inclusión (AU)

Amyotrophic lateral sclerosis (ALS) is a progressive, neurodegenerative fatal disease that affects motor neurons in the spinal cord, brain stem and motor cortex. It produces a failure of the motor system that directs, adjusts and maintains skeletal muscles, responsible for the ability to move and interact with the environment. We report the case of a 58-year-old male diagnosed with ALS, with atypical initial symptoms that hindered the final clinical judgement, and where inclusion body myopathy stood out during the differential diagnosis (AU)