Posture, balance control, movement: Involvement in vestibular rehabilitation

Abstract

The ability to move upright maintaining balance is a pre-requisite for most human behavior and independence. To maintain balance and to orientate, we use sensory information from vestibular, visual and somatosensory receptors (see above). The information is coordinated and integrated in the central nervous system (CNS) and modifies the motor control efferent command, which regulates the muscles that keep us upright. The motor command leads to correcting movements, which lead to new information from the sensory systems. In this aspect, the vestibular senses have a special and non-complementary role. Thus, changes in afferent sensory information arising from one or more receptor systems may affect the motor control performance by evoking and modifying the motor output elicited at all levels from the spinal medulla to the cerebral cortex. However, it has become evident that the different sensory systems, the neural control as well as the cognitive attitude all interact in achieving and expressing what human postural control is. All these players operate in concert with overlap, redundancy and adaptive capacity. Therefore, a lesion of one function will most often have an effect on several other components. Thus, a more advanced research methodology is necessary to reach useful understanding and interventions. Therefore, we need a system-biology or system-medicine approach both to analyse and to treat loss of balance and especially when it depends on vestibular loss. Vestibular rehabilitation’ is a physiotherapeutic approach to help regain balance after vestibular lesions with maladaptation. In patients with Meniere's disease not responding to conservative treatment, vestibular nerve section or transtympanic gentamicin is the last option to achieve vestibular ablation. However, this causes the subjects to suffer from acute unilateral vestibular loss. In patients with vestibular schwannomas and with remaining vestibular function, surgery will cause a combined effect of an acute unilateral vestibular lesion and manipulation of the cerebellum with possibly compromised compensatory mechanisms. These patients form a model of vestibular rehabilitation. We therefore train patients with rehabilitation even before the treatment and lesion. Our experience is that we reduce the time for recovery. We have seen occasional patients that have gone through a gentamicin treatment without any sick leave! In schwannoma patients, we see stunning postoperative recovery and may postulate that we will avoid some cases of lifelong incapacity due to combined cerebello-vestibular lesions. Furthermore, both frequency and time dispersing in training seem to be of major importance. In postural training, it seems that a 3 times a day schedule is not surpassed by more frequent training, which is of importance for planning the rehabilitation.