Here’s installment 3 in my series on research posters at the Movement Disorders Society conference in Copenhagen in August.  The first 2 posts covered treatment and non-imaging diagnostic testing, respectively.  The topic now is clinical features.  Don’t forget – these have not yet been submitted for publication in most cases.   All I have to work with are the abstracts, typically of about 400 words.  I don’t even have the full posters, much manuscripts.  I found 7 that I expect to survive the peer review process at respectable journals.  The first 4 are here.  Give me a couple of days for the last 3.  As before, my own editorial comments appear in italics.

The prevalence and characteristics of REM sleep behavior disorder in progressive supranuclear palsy patients.

A.P.H. Phoumindr, J.S.R. Srignean, R.B.H. Bhidayasiri (Bangkok, Thailand)

The set of symptoms called “rapid eye movement behavioral disorder” (RBD) occurs in 95% of people with Parkinson’s disease (PD) and in virtually everyone with dementia with Lewy bodies (DLB).  In RBD, one acts out dreams in the form of limb twitches; talking or shouting; sleepwalking; or even violent movement that can endanger the bedpartner.  In the morning, the patient recalls none of it.  For both PD and DLB, RBD can start years before the movement problem and is considered a major “pre-motor” predictive factor for those diseases.  It was originally thought to be rare in PSP, but more recent research has shown that it occurs in something like 30-40% of patients.  In this poster, neurologists in Bangkok, Thailand found that 10 (53%) of their 19 patients with PSP had experienced RBD.  The survey was performed after 6 years of PSP, on average.  

It’s hard to draw conclusions from the statistics because of the small size of the group, but the take-home is that a Thai population corroborates the general observation that RBD can occur in PSP.  Neurologists hearing of fragments of RBD in people with PSP should bear in mind the possibility of RBD because precautions against injury can be instituted and effective medication, usually melatonin or clonazepam, at bedtime can be started.  If the clinical symptoms seem diagnostically equivocal, a formal sleep study would tell the tale.

Impulse control disorder related to dopaminergic therapy in progressive supranuclear palsy

T. Thammongkolchai, P. Termsarasab (Bangkok, Thailand)

Two other neurologists from Thailand report one patient with PSP who experienced impulse control disorder, in his case pathological gambling and ice cream consumption, after starting pramipexole, a dopamine agonist medication.  This effect is well-known in Parkinson’s, where that drug class often provides good benefit, but this case shows that it can also happen in PSP, where dopamine agonists give little to no benefit.

This is another reason not to use the dopamine agonists in PSP without some special reason.  Whatever benefit they do provide is exceeded by the benefit of levodopa, which has far fewer side effects in PSP.  For a list of dopamine agonist drugs in clinical use world-wide, click here.

An acoustic-perceptual analysis of speech in clinical PSP phenotypes

G. Di Rauso, F. Cavallieri, A. Gessani, D. Fontanesi, S. Coniglio, V. Fioravanti, S. Contardi, E. Menozzi, S. Meletti, F. Antonelli, V. Rispoli, F. Valzania, C. Budriesi (Modena, Italy)This is a detailed, careful and very technical comparison of speech disturbances between 25 people with PSP-Richardson’s syndrome (PSP-RS) and 16 with PSP-Parkinsonism (PSP-P).  The researchers evaluated both the speech produced and the ability to understand speech.  They found no differences between the two subtypes and conclude that the formal diagnostic criteria for PSP-RS and PSP-P were justified in not attempting to use the type of speech disturbance to distinguish between them.

This finding makes sense because the main features of PSP dysarthria, spasticity (an explosive or rubber-band-like quality) and ataxia (a drunken-type, irregular pattern) are not part of the features distinguishing PSP-RS from PSP-P in other parts of the nervous system.  The finding is helpful in that it dissuades neurologists from trying to differentiate PSP-RS from PSP-P by their motor or perceptual speech abnormalities.  This is a fine example of a “negative” trial that is nevertheless important and useful.

Progression of the clinical features of progressive supranuclear palsy-Richardson syndrome in early and advanced stages

T. Xie, C. Liao, L. Golbe (Chicago, USA)

This project demonstrates that difficulty swallowing solids and liquids progressed faster late in the course of PSP, while all the other items in the PSP Rating Scale progressed at a uniform pace throughout the disease course.  The analysis was original in benchmarking each patient’s course not by calendar years, but by progression milestones of their own time downgaze palsy – a central feature of PSP.  It’s also unique in tabulating patients’ exam results from onset to within a few months of death, on average. 

Full disclosure: Yes, “L. Golbe” is yours truly.  Tao Xie (pronounced “she”) is a prominent neurologist at the University of Chicago with whom I’ve worked before and Chuanhong Liao is a biostatistician there.  Dr. Xie gets all the credit for the creative scientific thinking and the study design.  My most important contribution was a database of 462 patients I saw from 1994 to 2020 and evaluated with the PSP Rating Scale at each visit. The results can be used to counsel patients in symptomatic management.  They may also serve as “historical control” data in the long-term, open-label phase of neuroprotective treatment trials in which the double-blind phase lasts only 12 months and occurred much earlier in the course.  We have submitted a paper for publication.