About the Author
Dr Benjamin Sinclair attained his PhD at the University of Queensland and has worked as a lecturer in MRI physics at the University of Queensland and as a Research Fellow at the University of Melbourne.
His major area of study and research is in the field of brain imaging. Dr Sinclair has published papers on a range of topics including supernova cosmology, space plasma physics, the heritability of brain networks and effects of physical exercise interventions on brain atrophy in elderly people.
The Science of REVIVER
Thus far, self-reports by users of the REVIVER exercise machine and simple observations by Isodynamics centre staff indicate a myriad of benefits.
A number of users demonstrate immediate and marked improvements in walking and posture, which persists through regular use. Regular use also produces visually evident increases in muscle tone, and some users report improvements in memory and reduction in pain symptoms from pre-existing ailments.
In what follows, the probable scientific basis of the observed improvements is explored. The physical benefits obtained from the use of the REVIVER derive from improvements in both muscular and neural systems.
These improvements can be explained by a number of principles; neuroplasticity, neuromodulation, assisted motion, recruitment of full-body automatic/reflex actions and utilisation of gravity.
2. Neurological Effects
All motion other than simple reflexes originates in the brain. The brain and the bodywork as a single integrated system, and many physical impairments have origins in the brain.
In fact, improvement in any movement or action, from hitting a tennis ball to walking up the stairs results from refining and strengthening of the neural circuits which compute and execute these actions. The strengthening of these circuits comes about by repetition and adaptation in response to external feedback.
The drastic improvements observed after relatively short periods of use on the REVIVER exercise machine are most likely due to a process of neuromodulation.
Neuromodulation is the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body. In the context of therapy, neuromodulation is primarily used as a means of inducing neuroplasticity, which is described in the following section.
Neural activation is crucial for neuroplasticity to occur. For example, stem cells can replace damaged oligodendrocytes and re-insulate axons, but will only do so if the neuron is active, which is often not the case for damaged or disused tissue.
Neuromodulation for therapeutic purposes artificially activates natural intact pathways, and synchronises healthy neural tissue, leading to stronger connections and healthier neurons within these pathways (Kuo et al., 2014; Ridding and Ziemann, 2010). Neuromodulation can also enforce reconnection in malfunctioning tissue.
Neuromodulation has been used effectively for Parkinson’s Disease patients, whereby an implantable pulse generator is implanted in areas identified via Magnetic Resonance Imaging as defective.
This treatment generally reduces motor symptoms and most patients can reduce medication (Benabid et al., 2009). Neuromodulation has also been used effectively for Epilepsy patients, where the vagus nerve is stimulated, and 30-50% of patients experience a reduction in seizure frequency and severity (Ben-Menachem, 2002).
These therapies are quite invasive and require the implantation of a device. Less invasive methods involve the application of a miniature electrode array to the tongue, a technique developed by the Neurorehabilitation group at the University of Wisconsin.
This group applies the stimulation to the tongue at the same time as the patient carries out a movement task (Cranial Nerve, Non-Invasive Neuromodulation; CN-NINM). This combination is thought to be highly efficient at stimulating neuroplasticity (Danilov et al., 2007; Wildenberg et al., 2010). This technique yields large and rapid improvements in walking capabilities of traumatic brain injury and multiple sclerosis patients.
We have documented equally large and rapid improvements in low-mobility elderly participants and in one case a cerebral palsy patient.
The REVIVER uses a very similar principle to CN-NINM but is even less invasive. The stimulus is the periodic perturbation of the vestibular system via circular motion at a tilted angle.
Such a stimulation does not occur in day-to-day life. Although the input stimulus is not electrical, the stimulus (motion) will generate an electrical impulse in the vestibulocochlear (ear) nerve in much the same way as the microelectrode array in CN-NINM generated an electrical impulse in the hypoglossal (tongue) nerve.
The combination of a targeted stimulus (the circular motion) with physical activity (the contracting and relaxing of muscles required to maintain equilibrium), is likely to enhance neuroplasticity in damaged or disused motor and balancing circuits. In fact, given the strong neural interconnections between balancing and motor systems, we hypothesise that the vestibular system is a particularly appropriate target for neuromodulation.
The brain has an innate ability to heal itself, and to compensate for lost function by strengthening existing pathways, or recruiting new pathways should an existing pathway be irrevocably damaged. There are a large number of mechanisms contributing to this ability, which are collectively termed neuroplasticity, and are described below.
2.2.1 Structural plasticity
Neurons themselves can change structurally
Requires neighbouring neurons to fire in synchrony
Receiving (postsynaptic) neuron can increase the length and number of dendrites (the branches of the neuron which pick up incoming signals)
Transmitting neuron can create more axonal branches and terminals.
2.2.2 Synaptic plasticity
Neuroplasticity can occur at the terminal between two neurons.
When a neuron is repeatedly active
The amount of neurotransmitter released for each impulse (action potential) increases
The number of receptors on the receiving neuron can also increase.
Communication between neurons is critically dependent on the insulation of the wiring (axon)
Axon is covered in myelin
Speed of electric signal dependent on the amount of myelin
Use of a pathway increases the amount of myelin.
Thousands of new neurons are produced each day from stem cells
In the event of injury, stem cells migrate from their origin in the brain to damaged areas.
It is not yet known whether and under what conditions these stem cells can repair damaged tissues.
We cannot say which of the above mechanisms are specifically targeted by the REVIVER machine, but any alteration to brain function will be a result of one or multiple of the above mechanisms.
2.3. Exercise Effects on Brain Health
Some of the brain benefits from use of the REVIVER can be attributed simply to the more general benefits of any exercise to the brain. Humans evolved as a nomadic specie, constantly on the move, and today’s sedentary lifestyle does not provide the brain with the activity and nourishment needed for optimal performance.
Physical activity is extremely beneficial for brain health via a number of mechanisms. Exercise increases the creation of new brain cells (neurogenesis), increases the production of neurotrophic factors, which support the growth and survival of neurons and exercise increases blood flow to the brain (Hillman et al., 2008).
The primary cell in the brain is the neuron.
Neurons consist of a cell body which receives signals and performs calculations, and axons, which relay signals to other neurons. Grey matter is the term used to refer to the cell bodies of neurons. Exercise increases the volume of grey matter in the hippocampus, the area of the brain responsible for memory formation, and the prefrontal cortex, involved in working memory, attentional control, decision making and behavioural inhibition. White matter is the term used to refer to the axons of the neurons, and more specifically, the myelin which insulates the axons and improves conduction of electrical signals. Exercise improves the structural integrity of the white matter tracts in the brain, and thus improves communication between different regions of the brain (Sexton et al., 2016).
These positive effects of exercise on brain anatomy and physiology are accompanied by improvements in cognition, in particular executive function (Hillman et al., 2008; Hotting and Roder, 2013), which includes functions such as attentional control, planning and working memory.
It should be noted that the vast majority of studies looking at the effect of exercise on brain health consider aerobic exercise. The effects of resistance training are much less well documented. However, resistance exercise has been seen to improve executive cognitive function (Liu-Ambrose et al., 2012; Nagamatsu et al., 2012).
Since the Reviver allows people to perform movement they may otherwise be unable to perform, then a large part of the benefit of the Reviver derives from allowing people to tap into these benefits of exercise which were previously unavailable to them.
Furthermore, the improvements in muscle tone and balance acquired from using the REVIVER can allow elderly people to subsequently engage in more demanding activities, and thus further the neurological benefits of exercise.
2.4. The Motor System
The neural apparatus for executing movements is distributed throughout the brain. The primary motor cortex sends signals to the muscles via motor neurons telling them to contract. If the strength of this signal reduces, the efficacy of contraction reduces. But before this signal is sent to the muscles, a complex system of planning, feedback and modulation takes place in the brain.
The premotor areas plan sequences of movements and integrate movements with sensory information, the cerebellum calibrates the timing and precision of movements, the basal ganglia modulate and smooth movements.
Damage to any of these areas, or the connections between them will result in suboptimal movement. Additionally, non-use of these areas and circuits, either through physical impairment or changes in lifestyle will weaken the connections and excitability between the involved brain regions (Facchini et al., 2002; Kaneko et al., 2003). Conversely, the motor system displays a high degree of plasticity and can be strengthened through motor training (Adkins et al., 2006; Boroojerdi et al., 2001).
In summary, early observations indicate that the REVIVER is extremely promising as an exercise machine and even as a therapeutic tool.
Objective measurements and follow-ups will be needed to validate its efficacy and determine in which conditions it is most effective. These trials are currently in the planning stages.
At this point, we can say with very little speculation that the Reviver machine is particularly adept as a tool for elderly users with reduced function, as the machine assists them to perform motions beyond their current physical capabilities, and activates muscles which are rarely used in day to day activities and are thus subject to atrophy.
Rapid improvements in some users are best explained in terms of neurological, rather than muscular phenomena. The closest precedent in scientific literature is the emerging field of neuromodulation.
The REVIVER inputs a strong targeted and novel stimulus simultaneously to the user being engaged in some task, which is a hallmark of a number of more high tech neuromodulation strategies. This combination is thought to optimally stimulate neuroplasticity and strengthen the users' natural neural systems, which could explain the rapid improvements in walking and posture in some users.
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