The American Stroke Association claims that about 40 percent of stroke survivors have serious falls within a year of their stroke. In a study published in Stroke: Journal of the American Heart Association, (1) women stroke survivors who reported difficulty maintaining their balance while dressing were seven times more likely to fall than women who didn’t report balance problems.
Physical therapist Sapan Palkhiwala, from the Long Beach Memorial Balance and Vestibular Center in California, says the body uses a combination of three systems to stay balanced: vision, vestibular and somatosensory. The vestibular system monitors changes in your head movements with respect to the pull of gravity. It includes two parts: the central system (housed in your brain) and the peripheral system (in your inner ear). These systems are connected by the vestibular nerve. Some strokes or injuries affect the brainstem, and if this occurs, the vestibular system is vulnerable to damage. Symptoms of a brainstem stroke can be dizziness, or vertigo causing imbalance.
The somatosensory system relates to the perception of sensory stimuli from the skin and internal organs. Using this system the body picks up information where it can: from the pressure of the feet on the floor, for example, or the ankle positioning, to help balance the body.
More simply, clients – whether generally healthy or not – may experience balance problems simply because one side is stronger than the other, but they can build up their affected side by using it in every day movements, such as reaching and grasping. Constraint-induced movement therapy (CI therapy) forces patients to use their affected side while restraining their unaffected side. We can use this idea and adapt it by asking clients to put their stronger arm behind their back, and reach for a dumbbell or other free weight from a range of different positions using only their weaker arm, and then clean or press it.
Where there is unilateral weakness, we need to build up the weaker side by working it proportionally harder, in order to bring it up to – or at least nearer to – the level of the stronger limb. Training both sides equally will leave the disparity unchallenged.
Loss of vestibular function can be pretty devastating. In “The Brain that Changes Itself”(2), the author Norman Doidge relates a case of a woman who lost her vestibular function as a side effect of a prescribed drug. “Suddenly one day she discovered she couldn’t stand without falling. She’d turn her head, and the whole room would move. She couldn’t figure out if she or the walls were causing the movement.” She was tested and was found to have only 2 per cent vestibular function.
If the vestibular system is damaged, causing vertigo, motion sickness or dizziness, we can introduce exercises to re-train the brain to accept these movements and so reduce or eradicate the symptoms. For example, fixating on an object with your eyes while moving your head in different directions can train the brain to accept the discomfort, so that ultimately the symptoms begin to reduce. This approach can be repeated with other activities the client finds uncomfortable, such as walking up stairs while turning head from side to side. Trainers can also experiment with their clients balancing on shifting surfaces such as sand or using a Core-Tex. Because the client’s feet aren’t planted he can’t use them to get his bearings so that he will be obliged to use vision to keep balance.
Another viewpoint on balance comes from the book The Brain that Changes Itself. Here, the author explains how balance can be seen as a sixth sense, and normally works very efficiently; so that we fail to concede it is another sense. A fully functioning vestibular apparatus is markedly connected to vision, allowing us to move at speed and still focus on a visual target ahead, while the vestibular system feeds information regarding speed and direction of travel to the brain. These messages encourage the brain to allow movement at the eyeballs to adjust focus on the target.
Where the vestibular apparatus has been damaged, the sufferer finds it impossible to track a moving target with his eyes, images bounce about, and if vision is temporarily blocked (eg using a blindfold) he will instantly fall over, as he has no further clues to impart information to the brain. Even with sight restored, the images are erratic and the messages conflicting, so that the sufferer can often feel lopsided or experience a permanent sensation of falling. One of my clients, having suffered a series of strokes, can no longer track objects overhead: if he tilts his head, he falls over. When questioned, it transpired he only felt safe if he kept his gaze directly ahead of himself, neither turning to the left nor right. Any other movement he lost visual tracking capacity and he would fall.
In such situations, we want to develop a sense of balance, but we won’t necessarily know if that is viable purely through exercise. There are other issues worth exploring in the face of impaired balance, such as left/right recognition, sensory impairment at extremities, and visual disturbance. A rehab programme needs to be a measured programme that also takes into account the likely incidence of setbacks, plateaux, and good and bad days. With a basic understanding of this crucial element of human well being, you can help your client through the dips and troughs towards a sense of balance – literally!
(1) WHO report – A Global Report on Falls Prevention Epidemiology of Falls (2007)
(2) The Brain that Changes Itself, Norman Doidge