Balance training and visual rehabilitation of age-related macular degeneration patients

Patients with Age-Related Macular Degeneration (AMD) experience a large scotoma precluding central vision. In addition, 2/3 of these patients present visuomotor and balance deficits resulting in clumsiness and increased risk of falls. On the basis of previous work demonstrating that visual, vestibular and somatosensory functions involved in balance control can be rehabilitated by training, we attempted to improve these functions by balance training. We measured the impact of balance training on several visuomotor functions and reading speed. We compared balance status of 54 AMD patients to 55 normal controls. Sixteen of these patients and 14 controls subsequently received balance training sessions on a postural platform (Multitest) stressing sensorimotor coordination by selectively inhibiting or disturbing either, visual, vestibular or somatosensory input. Producing a conflict between two inputs reinforces the use of the third. We assessed postural sway, pointing accuracy, reading performance and, for the patients, the effect of low vision training and balance training on the shift from several spontaneous Preferred Retinal Loci (PRLs) to one or more Trained Retinal Loci (TRL). Even after a limited number of sessions of cross-modal balance training, the results show a significant improvement for the vestibular input and fixation stability. A decrease of visual dependency was observed only in the control group. Apart from these improvements, pointing accuracy and reading speed were not significantly improved compared to controls, leading to the conclusion that more training sessions may be necessary to gain more significant improvement of visuo-motor functions.