Effect of Vestibular Stimulation on Fat Consumption and Energy Expenditure as Assessed Using Indirect Calorimetry

There is a growing realization that obesity can, in many ways, be viewed as a neurological
disease triggered by lifestyle factors. There is clear evidence that the central melanocortin
system, which is centered in the arcuate nucleus of the hypothalamus, regulates a "set-point"
for how much fat the body should have. It does so by altering appetite and metabolic rate so
that deviations too far in either direction are strongly resisted. This set-point is
determined by genetic, epigenetic and lifestyle factors. Thus, excessive exposure to dietary
monosaccharides, such as glucose, and saturated fats, especially in childhood and
adolescence, can damage the neurons of the arcuate nucleus and push the set-point up. This
then can condemn sufferers to a lifetime of obesity, despite individual efforts to combat it
using diet and/or exercise.

Establishing a method of tuning down the set-point for body fat thus has to be a goal if the
current obesity pandemic is to be successfully combatted. A significant amount of animal work
suggests that stimulating the vestibular system in the inner ear, by means of chronic
centrifugation, actually does just that and causes a reduction in body fat. This is likely
because chronic vestibular activation is taken by the brain to represent a state of increased
physical activity, and in order to optimize homeostasis it would be appropriate for the body
to have a leaner physique, by reducing unnecessary energy expenditure from carrying excess
fat.

It is possible to stimulate the vestibular nerve in humans by applying a small electrical
current to the skin behind the ears. This is an established technology that is believed to be
safe, but only previously used for research purposes. The investigators found in a pilot
study that recurrent stimulation of this kind for two or three hours a week over four months
led to a statistically significant reduction in truncal fat in the active group as opposed to
the control group who underwent sham stimulation.

Given the current, and increasing levels of global obesity, it is important to determine
whether non-invasive electrical vestibular nerve stimulation (VeNS), otherwise known as
galvanic vestibular stimulation (GVS), is a viable treatment option, since if it were this
would be of significant scientific importance.

The investigators wish to use the technique of indirect calorimetry to explore this. This
involves wearing a tight face mask to collect all inspired oxygen and expired carbon dioxide
and using formulae to calculate total energy expenditure and the component of metabolism that
is derived from fat as compared to carbohydrate.

Inclusion Criteria:

1. Signed informed consent

2. Body mass index (BMI) > 25 kg/m2

3. 18-65 years of age inclusive on starting the study.

4. Successfully completed the screening questionnaire.

Exclusion Criteria:

1. History of vestibular dysfunction.

2. History of bariatric surgery, fundoplication, gastric resection or major
upper-abdominal surgery (acceptable surgeries include cholecystectomy, hysterectomy).

3. History of skin breakdown, eczema or other dermatological condition (e.g. psoriasis)
affecting the skin behind the ears, or of the head and neck.

4. History of weight loss device implantation (e.g. VBloc Maestro or Abiliti).

5. Positive response in Physical Activity Readiness Questionnaire.

6. Currently taking medication for asthma or other breathing conditions.

7. Untreated thyroid disorder (stable treatment for 3 months is acceptable).

8. Other endocrinological causes of weight gain (e.g. Cushing's disease, Cushing's
syndrome or acromegaly)

9. Previous diagnosis of HIV infection or AIDS (HIV is known to cause a vestibular
neuropathy which would prevent VeNS from working).

10. History of cirrhosis, or liver, kidney or heart failure.

11. Chronic pancreatitis.

12. Treatment with prescription weight-loss drug therapy in the year before starting the
study.

13. Tobacco or marijuana smoking in the 6 months prior to study.

14. Known genetic cause of obesity (e.g., Prader-Willi Syndrome).

15. Diabetes mellitus (Types 1 & 2).

16. Diagnosis of epilepsy or use of anti-epileptic medication within six months of
starting the study (e.g. for the treatment of peripheral neuropathy)

17. Chronic (more than a month of daily use) treatment with opioid analgesic drugs within
the last year.

18. Regular use (more than twice a month) of anti-histamine medication.

19. Use of oral or intravenous corticosteroid medication within two years of starting the
study.

20. Use of the beta-blockers atenolol, metoprolol or propranolol within 3 months of
starting the study.

21. Current use of tricyclic antidepressant medication for whatever reason.

22. Current alterations in treatment regimens of anti-depressant medication for whatever
reason (other than tricyclic antidepressants) (Note: stable treatment regimen for
prior six months acceptable).

23. An active diagnosis of cancer.

24. A previous myocardial infarction.

25. A history of stroke or severe head injury (as defined by a head injury that required
intensive care). (In case this damaged the neurological pathways involved in
vestibular stimulation).

26. Presence of permanently implanted battery powered medical device or stimulator (e.g.,
pacemaker, implanted defibrillator, deep brain stimulator, vagal nerve stimulator
etc.).

27. Psychiatric disorders (including untreated severe depression, schizophrenia, substance
abuse, bulimia nervosa etc.)

28. Current participant in a clinical trial for weight loss.