It is very well documented that sensory information is necessary for efficient postural control and balance. It is also well known that it is possible to balance and be involved in sport without vision. However when we are moving through the environment we use vision to sample the environment coming up, and assist us in anicipatory postural adjustments (APA’s). This allows us to be much more working on a feedforward ‘preparatory’ basis and not a feeedback ‘reactive’ kind of balance.
I have just returned from a skiing holiday in France where the first three days had huge amounts of snow, such that the piste was well covered and soon very bumpy, but more importantly the visibility was very poor.
I became very aware of how much I rely on vision to anticipate the necessary postural readiness and assist in muscular adaptation to the undulations in the bumpy piste.
I have a vestibular hypofunction so I have realised that in the dark my balance is not so hot. However being unable to determine if the slope I was on was inclining or declining or sideways, because of the poor visibility, meant that my postural control and movement efficiency were so much worse than usual
Since we normally have an efficient anticipatory postural control system we can minimise the need for the corrective compensatpry postural adjustments. Skiing this week, with reduced sensory information from my eyes to guide this mechanism, meant my muscles were working much harder in response to fear of falling. My ‘preparedness’ for the upcoming motor plan was diminished and so I was acting in a less efficient way – using feedback corrective mechanisms more heavily instead.
This made me acutely aware that many of my patients with decreased ability to integrate sensory information and so develop APAs will be also functioning in a feedback way and so their fatigue in doing every day activity such as walking is understandably much more fatiguing than normally.
I have always been aware of the ability for blind people to ski and I have always felt that is quite an achievement to entirely rely on somatosensory info for balance control; but after my week skiing in these difficult conditions my respect is so much more!
I tried to redress the balance between the sensory systems so that I could improve my use of somatosensory rather than visual information. Weighting sensory information in this manner is something the CNS does readily to use the sense most relevant to the task in hand.
I began to practice taking turns in good visibility (on a clear piste to protect my fellow skiiers!) with my eyes closed.
This developed my ability to use the somatosensory information more, and not just the limited visual information, so I was more able to feel the piste and therefore recalibrate my balance system, so I became less dependent on vision, more relaxed, less fearful and so much more able to adapt to changes in the piste.
This also made me reflect about the neurological patient who learns to become very dependent on vision at the expense of confidence in balance, so if the visual environment suddenly changes they are at risk of falling. Therapy often tries to change this weighting and decrease dependence on vision
From personal experience it certainly helps!
If you would like to deepen your understanding of Postural Control mechanisms and balance systems, then consider joining one of our Problem Solving Workshops, or Advanced Courses – see the Courses section of the BBTA website