Background
Falls represent a major health problem in elderly subjects because of their high prevalence and the seriousness of their physical, functional, psychological and financial consequences. Indeed, about 30% of independent people living in the community over 65 years old and 50% of those over 80 years old suffer at least one fall per year; a third of the fallers experience repeated falls [
1]. The human and economic cost of falls increases along with the aging of the population, particularly in Western societies. In 2015, EuroSafe (European Association for Injury Prevention and Safety Promotion) [
2] classified falls as the 3rd most common cause of disability among the elderly and one of the main causes of admission to specialized institutions.
Prevention of falls is widely recognized as one of the priorities for healthy and active aging of the population. Most recommendations for fall prevention, such as STEADI [
3] or The ProFouND [
4], call for regular assessments of elderly patients at risk and the provision of appropriate interventions. Van Voast Moncada et al. [
5] summarized the different interventions evaluated in the literature, such as therapeutic education, dietary supplementation, functional rehabilitation to improve walking, strength or balance, treatment of hypotension, review of medication, podiatry or even management of vision problems or home design. Taken separately, each intervention has only a moderate impact on the risk of falling, and elderly people at risk of falling should be offered a broader protocol combining different methods [
6]. Prevention of physical deconditioning is a prerequisite for "successful aging" [
7]. Various elements have been identified as physical components [
8] that contribute to the maintenance of autonomy and can therefore be used as a control during management. In elderly people who fall, there is a maladaptation of the balance strategy: weakened postural and general control, impaired visual feedback, as well as impaired proprioceptive and vestibular systems and neuromuscular coordination [
9,
10]. The loss of lower limb strength directly influences Walking Speed (WS) [
11], which is a recognized marker for predicting the risk of falling and is correlated to static and dynamic balance [
12]. Age leads to the appearance of a cautious attitude with a reduction in WS [
13] and a change in the distribution of support on the ground with an increase in pressure peaks at the level of the hindfoot and a decrease in support at the level of the hallux [
14‐
16].
Spinal curvatures change with age, tending to a general increase in curvatures, an increase in asymmetries and an protraction of the head [
17,
18] which may influence balance in the senior citizen. The neurological system also undergoes major modifications with a reorganization of the motor units [
19], a decrease in the number of mechanoreceptors, and an alteration of the function and vestibulospinal reflexes [
20]. Finally, the aging of the autonomic nervous system and more particularly of its parasympathetic component [
21] may indirectly influence balance through its link with the cardiovascular system [
22]. This is why the analysis of Heart Rate Variability (HRV) is a good indicator in the evaluation of the risk of falling due to orthostatic decrease in the elderly [
23].
From a clinical point of view, the cervical spine could be of particular importance due to its position and constitution: at crossroads of articular, visual and vestibular proprioceptive afferents, rich in neurological and motor elements [
24‐
26]. Its role is mechanical (shock absorption of movements [
27] and stabilization of vision [
28]); but also neurological (regulation of the autonomic nervous system). Quek et al. [
29], have shown that a decrease in cervical mobility and the presence of rotational asymmetry caused an alteration in anteroposterior oscillations during static equilibrium. They hypothesize that in subjects unable to effectively recruit the muscular and proprioceptive system of the neck, a compensatory system based on vision and vestibular system comes into play. This suggest that preserving cervical movement capacity across lifespan could limit compensations and risk of falling. The role of the tone of the cervical musculature seems to be essential since it has been shown [
30] in young subjects that muscular fatigue in that area reduces the speed of displacement of the Center of Pressure (CoP), and in elderly subjects there is a modification of the recruitment pattern of the neck muscles in favour of the superficial muscles (to the detriment of the deep muscles) which favours the modification of the cranio-cervical angle and the orientation of the lordosis, generating an protraction of the head [
31].
If the management of the cervical spine seems to be of interest in balance strategy, its vascular and neurological environment makes investigation and local treatment delicate especially in elderly. Myofascial Release (MFR), which is a form of manual therapy, seems particularly appropriate as it is non-invasive and can be adjusted to the recommendations of use. MFR needs application of a low load, long duration stretch to the myofascial complex, intended to restore optimal length, decrease pain, module neural transmission and improve function. The effects of neuromuscular stimulation of the cervical region remain poorly explored. Studies have shown that the application of vibrations to the cervical spine improves sensorimotor function and decreases postural sway in subjects with neck pain, while it alters head positioning in healthy subjects [
32,
33]. Applied on C4 level this technique could provide stimulation of the carotid sinus and its baroreceptors, the superior cervical ganglion, the nuchal ligament, the longus neck muscle and the vestibulospinal reflex. An other technique commonly applied in MFR, usually called “suboccipital decompression”, seems to have an interesting impact on different postural determinants, in particular the cranio-cervical angle, the position of the head or even the stiffness of the posterior chains of the lower limbs [
34,
35]. This technique enables an action on the oculo-cephalogyre muscles (the rectus capitis posterior major and minor, obliquus capitis superior and inferior) and the vestibulospinal reflex as well as the upper cervical proprioceptors, the neurovegetative structures of the posterior torn hole (X and XI) and of the carotid corpuscle by anastomosis. Other manual protocols aimed at the myofascial system as a whole or more specifically in the neck region have been evaluated and seem to indicate a favourable effect on balance, especially on anteroposterior sway [
36] which is a parameter characterizing the displacement of the CoP, cervical mobility [
37,
38] or even the Time Up and Go Test (TUGT). Unfortunately, these studies are sometimes of questionable methodological quality whether this is because of a small number of subjects, the absence of a controlled or placebo group or even a timing of different treatments depending on the groups.
However, there is no consensus on the frequency or number of treatments necessary with MFR, regardless of the reason for which they are used, for example: chronic low back pain, fibromyalgia, functional capacities… [
39,
40]. Whatever the modality of application (massage or osteopathic manual therapy) or location (lower limb or trunk) it seems that only one MFR session have a limited or even non-existent effect on balance [
41,
42] while recent studies have shown that two sessions can [
43,
44].
To our knowledge, no study has yet proposed to evaluate the effect of a cervical spine MFR protocol on balance in older adults. The main hypothesis of the present study is that a two sessions MFR protocol have a beneficial impact on the balance and motor performance of older adults, which will result in improved balance and WS in the experimental group compared to the placebo group. The study also aims to propose an assessment of the physical parameters of balance, looking for links to validate the contribution of the cervical spine in compensatory mechanisms.
Primary and secondary objectives
The primary objective of this work will be to evaluate the influence of some MFR techniques address to cervical spine on WS and SPPB (Short Physical Performance Battery test) score. It can be assessed by the main hypothesis:
H0: SPPB score and WS of MFR protocol group ≤ SPPB score and WS of light touch group.
H1: SPPB score and WS of MFR protocol group > SPPB score and WS of light touch group.
Secondary objectives will be to evaluate the influence of the protocol on other measured balance parameters, including cervical strength and mobility as well as lower limb strength, ground support and HRV. The data can also be used to explore the relationships between the different parameters.
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