Introduction: Retinoblastoma is a rare type of childhood genetic cancer that affects children worldwide. The diagnosis is often missed due to lack of education and difficulty in presentation of the tumor. Frequently, the tumor on the retina is noticed by photography when the red-eye flash, commonly seen in normal eyes, is not produced. Instead, a yellow or white colored patch is seen or the child has a noticeable strabismus. Early detection can be life-saving though often results in removal of the affected eye. Remaining functioning in the healthy eye when the child is young has resulted in super-vision and high or above-average intelligence. Technological advancement of cameras has helped in early detection. Brain imaging has also made possible early detection of neurological diseases and, together with the monitoring of cortisol levels and yawning frequency, promises to be the next new early diagnostic tool for the detection of neurological diseases where cortisol insufficiency is particularly salient, such as multiple sclerosis and Cushing’s disease.
Methods: Eighty-two volunteers were recruited from students and the research volunteer pool at Bournemouth University using the computerized recruitment system and Facebook. All participants were properly consented according to code of conduct and research guidelines, and exposed, under randomized controlled trials guidelines, to three conditions intended to provoke a yawning response – photos of people yawning; boring text about yawning; short video of person yawning. Comparisons were made with people exposed to the same conditions but who did not yawn.
Saliva samples were collected at start and again after yawning response [Fig. 1], together with electromyography data of the jaw muscles to determine rest and yawning phases of neural activity
Results: There were no significant differences between groups in terms of age, HADS anxiety and depression scores, and GHQ28 scores. Normative data for saliva cortisol is known, and lies within the following ranges: (a) Morning collection is
3.7 to 9.5 nanograms (one billionth of a gram or 10-9) per milliliter of saliva; (b) Noon collection is 1.2 to 3.0 nanograms per milliliter; (c) Evening collection is 0.6 to 1.9 nanograms per milliliter.
In saliva cortisol sample 1, the means for non-yawners was
2.1 (SD = 1.67), and for yawners was 2.6 (SD = 1.99). In sample 2, the means were 2.2 (SD = 1.72) for non-yawners, and 3.1 (SD = 2.26) for the yawners. Hence, the yawners had higher levels of resting and post-experiment saliva cortisol levels than the non-yawners. In addition, there was a significant difference between sample 1 (saliva cortisol) and sample 2 (saliva cortisol) amongst the yawners: t (37) = 2.842, p = .007.
For the yawners, at rest, the EMG range was -100 to 200 millionth of a volt (mean of 182.2) as compared with -60 000 to 18 000 (mean of 3 897.4) after yawning. For non-yawners,
the range was -80 to 120 (mean of 37.2) and -400 to 800 (mean of 57.5) after the stimuli presentation. Therefore, the yawners tended to show a larger peak following the yawn as compared with the non-yawners, post-stimuli.
Conclusion: Potential application of these findings is in the diagnosis of neurological diseases such as in immune suppression syndromes where cortisol is important for good health maintenance.
The release of cortisol into our circulation system appears to have many roles, including protection and regulation of other neurochemicals. Yawning and cortisol is of particular interest and whilst still presenting a scientific conundrum in terms of its origin and mechanism, research has indicated that it features in a number of neurological disorders as well as in healthy individuals.
Cortisol is of interest to clinical scientists, practitioners, neurologists and neuroscientists because of its importance in stress response within the HPA-axis. Identifying threshold levels of cortisol and the recruitment of brain region activity may be important in determining future functioning deficits and neuronal damage.
Image capturing technology is also particularly useful for the detection for Rb, and with the advent of sophisticated camera technology, early diagnosis of Rb is made more possible. It is hoped that this technology can be put to good use and for the benefit of all individuals who have had neurological or genetic diseases impaired in the near future.