Impaired perception of surface tilt in progressive supranuclear palsy

Abstract

IntroductionProgressive supranuclear palsy (PSP) is characterized by early postural instability and backward falls. The mechanisms underlying backward postural instability in PSP are not understood. The aim of this study was to test the hypothesis that postural instability in PSP is a result of dysfunction in the perception of postural verticality.MethodsWe gathered posturography data on 12 subjects with PSP to compare with 12 subjects with idiopathic Parkinson’s Disease (PD) and 12 healthy subjects. Objective tests of postural impairment included: dynamic sensory perception tests of gravity and of surface oscillations, postural responses to surface perturbations, the sensory organization test of postural sway under altered sensory conditions and limits of stability in stance.ResultsPerception of toes up (but not toes down) surface tilt was reduced in subjects with PSP compared to both control subjects (p≤0.001 standing, p≤0.007 seated) and subjects with PD (p≤0.03 standing, p≤0.04 seated). Subjects with PSP, PD and normal controls accurately perceived the direction of gravity when standing on a tilting surface. Unlike PD and control subjects, subjects with PSP exerted less postural corrective torque in response to toes up surface tilts.DiscussionDifficulty perceiving backward tilt of the surface or body may account for backward falls and postural impairments in patients with PSP. These observations suggest that abnormal central integration of sensory inputs for perception of body and surface orientation contributes to the pathophysiology of postural instability in PSP.

Cutaneous sensory and autonomic denervation in progressive supranuclear palsy

“…Moreover, the loss of mechanoreceptors and related myelinated tural instability [39] that is more relevant in PSP.…”

“…The loss of cutaneous sensory nerves may account for the occurrence of sensory symptoms that were present in 60% of PSP and 29% of PD patients, in line with a greater loss of unmyelinated and myelinated nerve endings and with a lower amplitude of sural nerve action potentials in the former compared to the latter group. Moreover, the loss of mechanoreceptors and related myelinated endings, may contribute to the central mechanisms producing postural instability [39] that is more relevant in PSP.…”

Gait and balance disturbances are common in young urbanites and associated with cognitive impairment. Air pollution and the historical development of Alzheimer's disease in the young

“…Gait, equilibrium and postural disorders are linked to neurological and neurodegenerative pathologies. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 Gait is a complex activity requiring the activation of the cerebral cortex, basal ganglia, cerebellum, brainstem, spinal cord and the musculoskeletal system. 14 , 15 , 16 , 17 , 18 Independent papers by Kaoru Takakusaki, Klaus Jahn and Anat Mirelman et al, 14 , 15 , 16 extensively discuss human locomotion and the key regions associated with gait and posture i.e., the mesencephalic locomotor region (MLR) and its projections to the pontomedullary reticular formation; the subthalamic locomotor region (SLR) and the cerebellar locomotor region (CLR).…”

Vestibular Deficits in Neurodegenerative Disorders: Balance, Dizziness, and Spatial Disorientation

“…However, how much this contributes to postural instability and falls in comparison to other factors is yet to be elucidated. Indeed, findings of impaired proprioceptive sensory inputs in PSP indicate it is likely to be an abnormality in central sensory integration, rather than a sole vestibular deficit ( 46 ). Dale et al performed postural stability tasks on PSP patients versus healthy controls, finding patients with PSP had an inability to perceive backward tilt of the surface or body.…”