Tomi Sarkanen, MD, on Narcolepsy Scales
The Ullanlinna Narcolepsy Scale (UNS) is an 11-item questionnaire used to measure the symptoms of narcolepsy in adults and children. But how well does it compare with other narcolepsy scales? A new study1 sought to find out.
Neurology Consultant caught up with lead author Tomi Sarkanen, MD, who is a neurologist in the Department of Neurology at the Tampere University Hospital in Finland and in the Department of Neurological Sciences at the University of Helsinki in Finland.
Here are his responses to our burning questions.
NEUROLOGY CONSULTANT: Can you give us some background on your study? How did it come about?
Tomi Sarkanen: My personal interest on narcolepsy started at a conference I attended during my residency in neurology in 2012. At that time, I knew little about narcolepsy, and before that conference I thought other topics, like restless legs syndrome and Parkinson disease, would be more interesting. The conference presentations from top narcolepsy researchers were eye-opening and showed me that narcolepsy syndrome was incredibly complicated and fascinating.
At that time, the media attention on narcolepsy in Nordic countries had increased dramatically. There were large numbers of new narcolepsy cases, especially in younger age groups. These patients also had sudden onset, severe symptoms and significant behavioral problems. Earlier studies had reported that diagnostic delay in narcolepsy is rather long, on average more than 10 years. These patients, however, presented much earlier, even before media awareness was raised.
I was also interested in methods and possible biases in observational studies that reported the risk since, for example, in China there was a 3-fold increase in number of new narcolepsy cases, without association with vaccine.
NEURO CON: Tell us more about your findings. Did any of them surprise you?
TS: Maybe the most elementary finding was that narcolepsy is a very heterogenous disease in terms of symptom severity. It is difficult to find an explanation for why someone with similar sleep study findings and cerebrospinal fluid hypocretin/orexin levels does much better or worse than another. Medication side effects were also relatively common among the participants.
I was also a bit surprised about the consistency of risk among countries where the Pandemrix vaccine was used in large amounts. Moreover, it is also surprising that there seems to be no risk associated with the similar Arepanrix vaccine or any other vaccine, or H1N1 infection (excluding China).
The UNS also seems to be a very useful tool in clinical practice to help determine the pre-test probability of positive or negative multiple sleep latency test result. Although the UNS was developed for screening for narcolepsy in the general population in epidemiological studies, it seems to also work very well in sleep clinics. A cut point of 14 identifies narcolepsy patients with high sensitivity and specificity.
NEURO CON: How will your results impact clinical practice?
TS: These results emphasize individual treatment of narcolepsy. Medication side effects also need attention, as they might substantially lower the quality of life in these patients. Fortunately, new treatment options are emerging. The UNS is also something that I would recommend using routinely for sleep patients and possibly also in patient follow-up.
NEURO CON: What is the next step in your research? What else do you plan to study?
TS: There would be many interesting things to look for, but the next steps would be identifying the factors that affect the phenotype of narcolepsy patients. Is it some biological, possibly compensatory factor? Or is it some psychological aspect or trait? And if it is, how could we improve or strengthen positive coping mechanisms?
Even if the UNS seems like a good tool clinically, we will also continue to look for other tools that might capture narcolepsy symptoms more comprehensively.
NEURO CON: What is the key takeaway from your study for neurologists?
TS: Only the Pandemrix vaccination was associated with narcolepsy. It increased narcolepsy in young adults, especially in children. These patients need individualized therapy, and a good patient-doctor relationship is a cornerstone for comprehensive treatment. I would also recommend getting familiar with the UNS as a clinical tool.
Reference:
- Sarkanen T, Alakuijala A, Partinen M. Ullanlinna Narcolepsy Sale in diagnosis of narcolepsy. Sleep. 2019;42(3). https://doi.org/10.1093/sleep/zsy238