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SUMMARY:Puzzles\, Progress and Possible Directions for Persistent Postural
  Perceptual Dizziness (PPPD) - Professor Petroc Sumner (Cardiff University
 )
DTSTART:20221111T163000Z
DTEND:20221111T180000Z
UID:TALK178850@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:Our sense of balance occurs through integration of vestibular\
 , visual\, and proprioceptive signals. Conflict between these signals (e.g
 . in virtual reality) can create dizziness or nausea. However\, in a puzzl
 ing clinical condition disabling dizziness is triggered by visual motion t
 hat is unproblematic for most people (e.g. cinema) and often without theor
 etical cue conflict (e.g. supermarket aisles or walking past a railing / h
 igh contrast grating). These patients also commonly experience anxiety\, a
 nd sometimes even out-of-body or dissociative episodes (feeling ‘not the
 re’). The condition is Persistent Postural Perceptual Dizziness (PPPD) a
 nd the prevailing explanation is that patients have become over-reliant on
  vision (‘visually dependant’) following  a vestibular deficit\, and a
 re therefore destabilised by complex visual environments and motion. Howev
 er\, this general framework leaves many puzzles unanswered\, which we have
  begun to address: 1) why do some people develop PPPD and some not\, follo
 wing similar vestibular deficit? We found a spectrum of visually-induced d
 izziness in the healthy population (N=2335)\, with 10% in the patient seve
 rity range\, implying a predisposition to disabling PPPD should a vestibul
 ar deficit occur. 2) what is the nature of this predisposition? We found c
 orrelation with visual discomfort to stationary images that deviate from n
 atural scene statistics (r= 0.46\; N=1387)\, aligning PPPD with the visual
  discomfort literature\; and with sensitivity and aversion in other senses
  (e.g. to loud noises\, strong tastes\; r= 0.54\; N=1107)\, suggesting the
  predisposition is multisensory (it also correlates with migraine\, but fi
 ndings hold in non-migraineurs). 3) What does it mean to be ‘visually de
 pendent’? We found little correlation between measures of visual depende
 nce\, raising questions about how to define and measure the purported root
  of PPPD symptoms. The next steps are to unpack the nature of multisensory
  sensitivity\, and to model visual dependence using formal sensory integra
 tion frameworks.
LOCATION:Ground Floor Lecture Theatre\, Department of  Psychology
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