Age-related Changes in Movement-related Cortical Potentials

Abstract

Movement-related cortical potentials (MRCP) were measured in young normal subjects (age<40) and aged normal subjects (age≥60). All were right-handed. MRCPs were recorded for voluntary self-paced extension of the right middle finger or the right foot. For the middle finger extension the latency and slope of the Bereitschaftspotential (BP) and the negative slope (NS') were measured at the contralateral hand motor area, and for the foot movement they were measured from Cz. MRCPs for the finger extension were examined in 12 young subjects (5 men, 7 women, 22-38 years old, mean age 26.3±5.2 years) and 18 aged subjects (9 men, 9 women, 60-82 years old, mean age 69.4±7.2 years). BP latency and NS' latency were significantly longer in the aged subjects than in the young subjects (p<0.001 and p<0.05, respectively). MRCPs for the foot movement were measured in 10 young subjects (3 men, 7 women, 22-38 years old, mean age 27.1±5.4 years) and 10 aged subjects (5 men, 5 women, 60-82 years old, mean age 70.3±8.1 years). BP latency was significantly longer in the aged subjects than in the young subjects (p<0.05), but NS' latency was not. For both finger and foot extension, neither BP slope nor NS' slope differed significantly between the groups, although both slopes were steeper in the young subjects than the aged ones. These findings sugest that the time required by the cerebrum to prepare for voluntary movement and the period of preparation for movement are longer in aged subjects than in young subjects.