(Image from Dr S. Olvey's presentation slides at the ICMS 2016 AGM)

More concussion. We can't get enough of it. It has mushroomed over the past few years and is firmly in the public awareness, especially amongst sports competitors.

Until recently, there have been two levels of diagnosis; point of care and clinic-based. Point of care testing occurs on the sidelines or in the event medical centre and needs to be:
  • rapid,
  • easily applied,
  • cheap,
  • easily accessible
  • and have good test characteristics (sensitivity, specificity, PPV, NPV, repeatability, reliability and validity).
For this, in addition to clinical assessment we have test like the ImPACT, SCAT and King-Devick which we've discussed previously.

Clinic testing, while more accurate, tends to:
  • require specialised training to conduct and interpret
  • need a specific appointment to attend which take a reasonable amount of time
  • be conducted only at specific centres
  • be expensive

If only there was something to bridge the gap.

Luckily, some plucky researchers and engineers have taken a simple concept that uses bulky equipment and applied virtual reality style technology to try and develop a portable, easy to use and interpret diagnostic modality for concussion called the IPAS Goggles. And they sound great.

Prof. Michael Hoffer is one of the lead researchers on this project and I met him briefly at the recent ICMS meeting in Indianapolis where he showed me how the goggles work. He agreed to come on the podcast and discuss the background to the goggles and the evidence that his team has produced to date. He also talks about issues such as the potential to game some of the current sideline assessment tools that use a baseline, the potential for young, fit athletes to outperform tests even when impaired (similar to how they may outrun a treadmill ECG during assessment for chest pain) and a little bit about the potential for placing commercial gain over test validity for conditions such as concussion that may be hard to diagnose and yet have significant possible consequences and popular and media attention.

The IPAS set up at the ICMS conference.

An example of the real-time data display

Here's the podcast

Here are three papers that link vestibulo-occular deficit to concussion:

And an overview of occular defects in concussion in general:

Sports-Related Concussion: The Eyes Have It. Leonard V Messner. Department of Optometry, The Illinois College of Optometry, USA.

Here are the two published papers mentioned by Michael in the podcast:

Oculomotor, Vestibular, and Reaction Time Tests in Mild Traumatic Brain Injury. Balaban C, Hoffer ME, Szczupak M, Snapp H, Crawford J, et al. PLoS ONE 11(9)(2016): e0162168. doi: 10.1371/journal.pone.0162168. PubMed PMID:27654131
Clinical trials in mild traumatic braininjury. Hoffer ME, Szczupak M, Balaban C. J Neurosci Methods. 2016 Apr 30. pii: S0165-0270(16)30073-5. doi: 0.1016/j.jneumeth.2016.04.021. [Epub ahead of print] PubMed PMID: 27141855.

One concern regarding these goggles is that they rely on the concept of occulovestibular dysfunction (measured via reaction time; hence OVRT) reflecting the presence of concussion through disturbance of vestibulo-occular reflexes such as the optokinetic relex, cervico-occlar reflex and the vestibulocolic (not what you think that is) reflex. Reports suggest that anywhere between 10-80% of concussed patients with have an occulovestibular defect (either of version or vergence). So while the sensitivity of the goggles might be excellent in patients with an occulovestibular defect following concussion, what is it for a concussed patient with no OV deficit and therefore should test candidates be pre-screened for dizziness, vertigo, balance and visual impairment first?
(Version = saccadic movement, gaze fixation and smooth pursuit. Vergence = diplopia, accomodation, strabisumus)

If you want to know more, you can email Michael Hoffer directly or go and have a look at the NKI website.

What do you think? Possible game-changer?