Apraxia and motor control disorders in Rett syndrome: a longitudinal study in the first decade of life

Resumen

The sequential clinical features of motor behaviour deterioration were collected, from clinical examination and from retrospective and prospective video-recordings, in a series of 14 girls with Rett syndrome, at an age range from the second to the tenth years of life. The time of follow-up in each case ranged from 4 to 8 years (mean: 6 years 2 months). The hallmark motor features can be grouped in three periods. First (age 1-4 years): manual praxic skills (melokinetic and ideomotor) deteriorate until the subject is completely unable to perform purposeful actions with external objects. Second (age 2 1/2-7 years): abnormal approach-to-own-body gesturing becomes gradually more pronounced (finger-to-finger, hand-to-mouth, and hand-to-hand ''washing'' sterotypic patterns), as do active tactile reactions of avoidance of external objects. And third (age 7 years onwards): progressive dystonia in distal parts of lower limbs, hypomimia, deficit in rapid postural axial reactions and freezing, leading to progressive loss of locomotion. This sequence of praxic and motor control deterioration probably reflects a physiopathological background involving basal ganglia and their related frontal and parietal cortical regions. Motor disorders may act as a dungeon of some residual cognitive and interactive abilities in these subjects, thus parents and professionals may learn to use accurate signals to communicate with Rett syndrome patients.