MODIUS is a vestibular stimulation device – it activates the vestibular system by sending a small electrical impulse into the area behind each ear.
It was noticed in 2002 that vestibular stimulation causes a significant reduction in the body fat of animals. (Link)
The authors of this study commented that ‘after 8 weeks, percent body fat was significantly lower’, and that ‘it thus seems that the neurovestibular system can influence changes in body composition, particularly the mobilization and utilization of fat.’
Moreover, they also observed what they termed ‘a metabolic “shift” to a leaner state’, which they interpreted as supporting ‘a role for the neurovestibular system in modulating body composition’.
In fact, similar findings to this had been observed repeatedly over the previous decades – for instance, see this 1972 NASA research paper (Link) where a similar significant decrease in body fat was noted. However, the researchers on those occasions had mistakenly attributed their observations to non-specific effects, and failed to appreciate that it was vestibular stimulation causing the animals to become leaner.
While the previous application of vestibular stimulation, as demonstrated in the animal studies, is not practical for human use, it is possible to use a small electrical pulse to non-invasively activate the same part of the vestibular system that had been found to be important – i.e. the otolith organs that are involved in detecting horizontal movement (Link). This is the same technology that is delivered by MODIUS headsets.
In the laboratory setting, 15 human volunteers received vestibular stimulation while various assessments of both its immediate and longer-term impact were carried out. An initial study (Link) looking at the effects of repeated stimulation over a period of 16 weeks, in nine of these subjects, observed a significant reduction in body fat as measured by whole body DXA scans. The average reduction in abdominal fat in the active group was about 8% with the range being between 2 and 14%. This was statistically different from the control group and none of the volunteers changed their diets or exercise. In the immediate term, providing just one hour of vestibular stimulation was found in six fasted subjects to increase the secretion of the hormones insulin and leptin, while simultaneously decreasing appetite. Interestingly, even though these subjects fasted, this response would typically be observed after eating a meal.
Outside the laboratory, setting MODIUS has been utilized by people with varying lifestyles. The most significant result was seen in BODPOD scans at Ulster University, Coleraine. Over the period of one year, regular use of a MODIUS prototype, with an active and healthy lifestyle, brought about a 44% reduction in body fat, with a simultaneous 2kg increase in lean muscle mass in one participant. However, this result should not be viewed as typical.
These findings align with a significant amount of related research carried out by other scientists across the world.
While MODIUS is intended solely to assist adults with their weight loss and weight management goals, vestibular stimulation in general, due to its influence on the brain and endocrine system, has been researched as a therapeutic intervention in diabetes, high cholesterol, thyroid dysfunction, and as a means of reducing stress and anxiety.
MODIUS activates the vestibular system using a small electrical pulse. This activation then proceeds through to the brainstem and onwards into the hypothalamus. The hypothalamus is a crucial area in how the brain maintains stable internal physiological processes within the body, part of which includes fat storage and appetite.
In this regard, there is thought to be a ‘set-point’ in the hypothalamus that acts to regulate body fat. This acts to modify feeding behaviour and metabolic rate, in order to maintain body mass composition within set parameters and does so in order to optimize energy utilization. As such, deviations too far in either direction from the set-point are strenuously resisted. Thus, not only is it hard to change body mass composition via diet and exercise but even if you can, maintaining the new leaner composition in the long term is typically doomed to failure, as the brain, in effect, fights against the change.
Several areas within the hypothalamus are implicated in regulating this set-point, but a particularly vital one appears to be the arcuate nucleus with its populations of pro-opiomelanocortin (POMC), and agouti-related peptide (AgRP) / neuropeptide Y (NPY) co-expressing neurons. These neurons are part of the central melanocortin system, which acts by responding to circulating hormones, nutrients, and neuronal inputs. In the case of the POMC neurons, the response is anorexigenic with a decrease in food intake and an increase in energy expenditure. Conversely, the orexigenic AgRP/ NPY neurons act antagonistically to this.
The set-point for body mass composition that is determined by the central melanocortin system obviously varies from person to person and is influenced by both genetic and epigenetic factors. However, it appears that exposure to Western diets, particularly during childhood and adolescence, with their often excessive quantities of sugar and saturated fatty acids can damage neuronal populations within the hypothalamus and push the set-point for body fat upwards. This makes the overweight body composition appear to be the ‘new normal’ as far as the brain is concerned, and reverting to a leaner set-point once this has occurred can be very difficult.
As alluded to, the ability of vestibular stimulation to reduce total body fat appears to be mediated via a vestibulo-hypothalamic pathway. This reflects the vestibular system’s vital role in homeostasis and, indeed, vestibular input is known to project to multiple brainstem homeostatic sites, including the arcuate nucleus of the hypothalamus, which as stated, sits at the crux of the central melanocortin system.
Notably the medial vestibular nucleus is the main projection target of the utricle, which is the otolith organ that detects movement in the horizontal plane. Also, studies have shown that this same brain area is involved in the control of the sympathetic nerves running to fat deposits throughout the body. In summary, it appears that the central melanocortin system interprets activation of the medial vestibular nucleus (by horizontal movements stimulating the utricle) to indicate a state of increased physical activity. In such a state of apparent increased activity, it is optimal, from an energy conservation point of view, for the body to have a leaner composition, in order to reduce unnecessary energy expenditure from carrying around excess fat. Given its described connections to both sides of the autonomic nervous system the medial vestibular nucleus is well placed to reduce total body fat.
Thus, vestibular stimulation (such as that delivered by MODIUS), when repeatedly administered over time, causes recurrent activation of the medial vestibular nucleus, which we believe is taken by the central melanocortin system to indicate a state of chronically increased physical activity. When this happens, the body naturally shifts towards a physically leaner state.