Effects of lighting illuminance levels on stair negotiation performance in individuals with visual impairment

Publication date: Available online 16 January 2018
Source:Journal of Electromyography and Kinesiology
Author(s): Aliah F. Shaheen, Alexandros Sourlas, Khim Horton, Christopher McLean, David Ewins, David Gould, Salim Ghoussayni
BackgroundStair-related falls of older people cause a substantial financial and social burden. Deterioration of the visual system amongst other factors put older people at a high risk of falling. Improved lighting is often recommended. The aim of this study was to investigate the effect of lighting illuminance on stair negotiation performance in older individuals with visual impairment.MethodsEleven participants aged 60 or over with a vision of 6/18 or worse ascended and descended a staircase under: 50lx, 100lx, 200lx, 300lx and distributed 200lx lighting. A motion capture system was used to measure movements of the lower limb. Clearance, clearance variability, temporal and spatial parameters and joint/segment kinematics were computed.FindingsThere was no effect on clearance or clearance variability. Participants had lower speed, cadence, increased cycle time and stance time in the 50lx compared to 300lx and distributed 200lx lighting in descent. The minimum hip angle in ascent was increased in the 200lx lighting. Clearance was found to be moderately correlated with balance scores.InterpretationIndividuals with visual impairment adopt precautionary gait in dim lighting conditions. This does not always result in improvements in the parameters associated with risk of falling (e.g. clearance).



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