Wednesday, May 11, 2005

When Five Senses Become One - Sensory Integration and Virtual Rehabilitation

Gemma Calvert's review begins, "The past decade has witnessed a growing shift of emphasis away from the study of the senses in isolation and towards an understanding of how the human brain coordinates the unique sensory impression provided by the different sensory streams..." New technology has provided researchers with a glimpse of complexity of how primary senses interact, integrate, and are coordinated with each other. It looks like there are sites that integrate signals from different sensory modalities (like sight and sound) early in the processing pathway, in addition to late actors that coordinate the different received signals to convey a 'gestalt' view of the outside world.

The research itself is fascinating, but be aware that it will take years for the information to trickle down to many medical professionals, educational experts, and the public at large. With many sites for the integration of sensory signals to be affected, the clinical presentations are diverse. Look at the figure below.

There are some areas that are relatively selective for visual, auditory, or tactile motion processing, but other areas that seem to process various combinations of inputs. Knock any one out, and the others are affected. The computing brain will now receive inaccurate signals about motion, the result being mistakes in the gauging of self-movement (may act clumsy), the movement of others, and errors of sight (moving people, read text on a page) or sound etc. localization.

The downside of multisensory integration is that if one sensory modality is defective, there's a high likelihood that other senses can be affected too. In some cases this is good - like hearing becoming more sensitive in the setting of visual deprivation - but in others, the compensations may cause problems of their own (e.g. auditory hypersensitivity, hyperactivity from tactile, proprioceptive, or movement-seeking behaviors).

Interestingly, some of the new research technologies might also prove extremely valuable to future rehabilitation techniques. Researchers have already been able to demonstrate that functional imaging can visualize changes in brain activation when subjects voluntarily direct their attention toward or away from sensory stimuli (thereby affecting sensitivity and reaction times) but rehabilitation researchers want to carry the work a step further, for instance learning the best 'tweaks' optimize multisensory integration as well as motor recovery.

Multisensory Research (technical)
Multisensory Perception of Movement pdf
Multisensory Integration During Motor Planning pdf
Believable VIrtual Environment

No comments:

Post a Comment