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Published online before print January 16, 2008, doi:10.1212/01.wnl.0000304134.33380.1e)
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NEUROLOGY 2008;70:802-809
© 2008 American Academy of Neurology

Why do patients with PSP fall?

Evidence for abnormal otolith responses

K. Liao, MS, J. Wagner, MD, A. Joshi, MS, I. Estrovich, BS, M. F. Walker, MD, M. Strupp, MD and R. J. Leigh, MD

From the Neurology Service and Daroff-Dell’Osso Laboratory (K.L., A.J., I.E., M.F.W., R.J.L.), Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH; and Department of Neurology (J.W., M.S.), Ludwig Maximillians University of Munich, Germany.

Address correspondence and reprint requests to Dr. R. John Leigh, Department of Neurology, 11100 Euclid Avenue, Cleveland, OH 44106-5040 rjl4{at}case.edu

Background: Patients with progressive supranuclear palsy (PSP) fall frequently, beginning early in the course of their disease. Abnormal vestibulospinal reflexes are suspected, but the angular vestibulo-ocular reflex, which is mediated by the labyrinthine semicircular canals, survives late into the course of the disease.

Objective: To test the hypothesis that otolithic-mediated reflexes are abnormal in PSP.

Methods: We tested otolith-ocular reflexes (the translational vestibulo-ocular reflex [tVOR]) during combined rotation-translation in nine patients with PSP and nine age-matched control subjects; subjects viewed far and near targets. We also tested click-induced otolith-spinal reflexes (vestibular-evoked myogenic potentials [VEMPs]) in 10 patients with PSP and 30 age-matched controls.

Results: All patients with PSP had small tVOR responses during near viewing that were, on average, only 12% of those of control subjects (p = 0.001). Patients with PSP also showed a reduction of the amplitude of VEMPs compared to control subjects (median [range]: 54.3 [16.8 to 214] vs 149 [11.6 to 466], p = 0.001).

Conclusions: Taken together, these results indicate that abnormal otolith-mediated reflexes may be at least partly responsible for frequent falls in progressive supranuclear palsy, and deserve further study.

Abbreviations: aVOR = angular vestibulo-ocular reflex; NS = normal subject; PSP = progressive supranuclear palsy; RR = responsivity ratio; SCM = sternocleidomastoid; tVOR = translational vestibulo-ocular reflex; VEMPs = vestibular-evoked myogenic potentials.

e-Pub ahead of print on January 16, 2008, at www.neurology.org.

Supported by NIH grant EY06717, the Office of Research and Development, Medical Research Service, Department of Veterans Affairs, NASA/NSBRI NA00208, and the Evenor Armington Fund.

Disclosure: The authors report no conflicts of interest.

Received August 8, 2007. Accepted in final form October 16, 2007.






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