Review of OKN treatment for MdDS.
Timothy C. Hain, MD • Page last modified: May 10, 2023
See implementation of OKN stimulus that runs on your device:
Overview:
There are currently several "OKN treatments" offered for MdDS. By this we mean that the main intervention is visual stimulation. OKN means optokinetic stimulation, and usually refers to a large patterend visual stimulus that stimulates "nystagmus" or jumping of the eyes. The purpose of this page is to discuss the evidence concerning whether or not it helps.
 |
| Treatment Paradigm (From Dai et al, 2014). |
Dai protocol
Figure 4 from Dai et al, 2017, showing percentage of 141 patients with a reduction of 50% or more on symptom score, as a function of time after treatment. Dai et al (2014) reported "successful treatment" of MdDS in about 60% of cases using a procedure involving optokinetic visual stimulation and tilting of the head about the front-back axis (roll). The procedure involved multiple short sessions over a week. The study was uncontrolled, but subsequently there have been a small controlled study (e.g. Mucci et al, 2018). According to Cohen et al (2015), more than 100 patients have been treated with this protocol, and the "cure rate" is similar to the original report (about 60%). A recent follow-up (Dai et al, 2017), reported outcomes in 141 patients (122 females, 19 males). Their criteria for "significant improvement" was a reduction in the score on a symptom questionnaire by 50% or more. Patients were categorized as "classic" or "spontaneous" MdDS. They reported "significant improvement" in 78% of "classic MdDS", and 48% of "spontaneous MdDS". At one year, "significant improvement was maintained in 52% of classic, and 48% of spontaneous patients". They found that success was "generally inversely correlated with the duration of the MdDS symptoms and with the patients' ages".
The Cancieri et al (2018) online survey called the Dai protocol "VOR protocol". They reported that this protocol was tried in about 10% of their respondants. The VOR protocol rate of response was " (36.2%), then meditation (34.1%)". Or in other words, the Dai protocol was slightly better than meditation. Thats not medication, it's "meditation". Hm.
This protocol and result was replicated in about 25 patients in our clinical practice in Chicago, although we have discontinued this protocol due to logistical issues. We are dubious that roll adaptation explains MdDS, and for this reason we are also dubious about the rationale for this treatment. Still, it seems harmless and given that it seems occasionally successful clinically, we think it reasonable to try the home variant in MdDS patients that have not resolved with other treatment attempts
Dai and colleagues (2017) suggested that the optokinetic treatment is more successful in the classic motion triggered "MdDS", than the group variously called "rockers" -- also known as "spontaneous" MdDS, or non-motion triggered MdDS (which is an odd construction -- lack of motion triggering for a syndrome named for "debarquement"). This was also suggested by the Canceri et al (2018) survey (36% benefit for the OKN treatment in the motion triggered group, 20% for the spontanous). Pretty close to vitamins actually.
The initial rate of benefit is also higher in persons who have had MdDS for shorter times (e.g. 1 year as opposed to 3 years). After treatment, Dai et al (2017) found that there was partial regression, particularly in the "spontaneous" group, over about a year (see above for results in the "classic" MdDS group, that did better than the spontaneous). So far, a blinded trial has not been reported. We hope that this occurs. We no longer offer this treatment in our practice in Chicago. Logistics were just too difficult. We still maintain a home program page, for previous patients who are interested in a refresher.
Habituation:
The roll adaptation protocol of Dai et al (2014) could be reasonably viewed as a type of habituation. Motion sickness has been treated successfully with habituation (Dai, Raphan et al. 2011), and one might reasonably argue that MdDS, being a motion sickness variant, might also respond to a similar approach. Habituation entails a down-weighting of responses to motion input, and can reduce the long duration vestibular responses commonly associated with motion sickness susceptibility (Dai, Raphan et al. 2007).
Although there are well developed self-directed motion habituation protocols such as the PUMA exercises (Puma 2010), there are presently no published reports of their efficacy in MdDS (or motion sickness for that matter). Nevertheless, we are sympathetic to the general idea that things that make you feel worse (when you are dizzy) usually does result in some improvement (if you can stand it). The Puma protocol exercises are just so extremely stimulating that so far -- nobody amoung our MdDS patients has been able to tolerate them for more than a session or two. The Puma protocol exercises can be purchased on the web in the form of a DVD from Dr. Puma's website.
The OKN protocol reloaded --Vertical rather than horizontal
Yakushin et al (2022) reported that "This protocol was not effective in alleviating the MdDS pulling sensations.", here referring to the OKN/roll protocol described above. They indicated for their new protocol (see below) that " Overall, pulling symptoms in 72% of patients were immediately alleviated after the treatment and lasted for 3 years after the treatment in 58% of patients. The treatment also alleviated the pulling sensation in patients where pulling was not the dominant feature. Thus, the OKS method has a long-lasting effect comparable to that of OKS-VOR readaptation."
So perhaps this is a better OKN protocol ? I guess time will tell. If we recall, the original OKN protocol papers from this group suggested it succeeded about 60% of the time, but over time, it appears to score similarly to vitamins/minerals and psychotherapy. In their methods here they report "downward OKS to treat pulling forward and downward, leftward OKS to treat pulling right, and rightward OKS to treat pulling left. . " This paper is available online if you want to take a closer look. The implementation doesn't seem that hard - -just use an OKN stimulator that can be configured to similarly to the paradigm reported by Yakushin. We would think that bigger would be better -- i.e. a full field might be better than a cell phone. An OKN (oks) program that will run on your web device and goes left/right/up/down can be found here. We have had no experience with MdDS patients and this particular treatment, as of 2022.
Virtual reality as a way to deliver OKN.
We also think that a virtual reality (VR) type device (now they are down to about $200/Oculus Rift), combined with an active head movement protocol, might be fairly cost effective. Yakushin et al (2020) reported good results in a small group of 5 patients treated with VR. Certainly one could program a VR device to present an optokinetic stimulus that rotates with orientation to gravity. This is the same idea as the Dai protocol, just implemented with less cost. We are not sure if anyone has done this.
Along these lines, I have been told that the Newport-Mesa audiology practice in California offers a VR based treatment for MdDS (rented out). The general idea of using VR to implement vestibular habituation seems very reasonable to me. We don't see why it should be so expensive however. Right now, the lack of evidence or detail about the methodology of the Newport-Mesa process, makes this approach a bit worrisome. In addition to having no published evidence that it works, there is also no explanation as to what is happening. You can read more about the Newport-Mesa claims of "measureable, clinical improvement" here. Hopefully, this group will publish their results in a peer-reviewed publication. .
We think that what matters is how much you can reasonably stimulate the vestibular system, without having the person "bail" due to nausea. Protocols that gradually "ramp up" exposure, would seem fairly logical. Procedures that use the coriolis effect or pseudo-coriolis to create vestibular conflict also seem very reasonable. I would think that any successful device would also involve some nausea.
References: See here