Contribution of balance training in AMD patients' rehabilitation

Abstract In addition to central visual loss, 2/3 of the patients with Age-related Macular Degeneration (AMD) present balance deficits [J.P. Diard, et al., CIMM (Comite International de Medecine Militaire), vol. 71/3, 1998, p. 225.]. With aging, efficiency of sensory and motor functions decreases, resulting in falls [S.R. Lord, et al., Sensori-motor function, gait patterns and falls in community-dwelling women, Age Ageing 25 (4) (1996) 292–299.]. Balance control involves visual, vestibular, and somesthetic and motor interactions. It can be rehabilitated by training. We investigated the effect of AMD on balance, the effects of multi-sensory training on postural stability and sensory organization in elderly controls and AMD patients. In AMD patients, we measured the impact of rehabilitation on stabilization of an eccentric retinal fixation. We expect to foster the use of the visuo-vestibulo-proprioceptive loop and so to shorten the number of rehabilitation sessions needed. We compared the results of 15 patients (60–90 years old, central scotoma, 1.7   0.5 LogMAR), with those of 13 age-match controls. We measured balance status and training efficiency on a postural platform (Multitest Framiral®), stressing sensorimotor coordination by selectively inhibiting or luring either visual, vestibular or somesthetic information. Producing a conflict between two systems implies the reinforcement of the other system. We assessed benefit of balance training on three visuomotor tasks: finger pointing accuracy, shift of PRL to TRL and reading performance (not related here). Preliminary results indicate that training balance accelerates sensory reorganization and, for AMD patients, improves visual information integration used in stabilization of eccentric fixation and accuracy in visuomotor tasks. These results suggest that sensory and motor processes interfere with visual processing in cross-modal balance training.