Why do patients with PSP fall? Evidence for abnormal otolith responses

• Published in: Neurology Vol. 70; no. 10; p. 802
• Main Authors: Liao, K, Wagner, J, Joshi, A, Estrovich, I, Walker, M F, Strupp, M, Leigh, R J
• Format: Journal Article
• Language: English
• Published: United States 04.03.2008
• Subjects: Accidental Falls; Aged; Efferent Pathways - physiopathology; Female; Head Movements - physiology; Humans; Male; Middle Aged; Oculomotor Muscles - innervation; Oculomotor Muscles - physiopathology; Otolithic Membrane - physiopathology; Postural Balance - physiology; Reflex, Abnormal - physiology; Reflex, Vestibulo-Ocular - physiology; Saccule and Utricle - physiopathology; Semicircular Ducts - physiopathology; Supranuclear Palsy, Progressive - complications; Supranuclear Palsy, Progressive - physiopathology; Vestibular Diseases - diagnosis; Vestibular Diseases - etiology; Vestibular Diseases - physiopathology; Vestibular Function Tests; Vestibular Nuclei - physiopathology; Vestibule, Labyrinth - physiopathology
• ISSN: 1526-632X
• DOI: 10.1212/01.wnl.0000304134.33380.1e

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