Relative Difficulties of Daily Living Tasks with Retinitis Pigmentosa

Abstract

Purpose To determine the relative difficulty of activity of daily living tasks for people with retinitis pigmentosa (RP). Methods Participants with RP (n = 166) rated the difficulty of tasks (n = 43) underpinning the Dutch Activity Inventory goals of mobility indoors and outdoors, shopping, and using public transport. Demographic characteristics were also determined. Responses were Rasch analyzed to determine properties of the scale, derive unidimensional subscales, and consider differential item functioning (DIF). Results After removal of one ill-fitting item, the remaining 42 tasks formed a scale with reasonable Rasch parameters but poor unidimensionality. The most difficult tasks were orienting in poor and bright light both indoors and outdoors, and avoiding peripheral obstacles outdoors. Eight subscales were derived with unidimensional properties, each of which could be considered as requiring similar skills. DIF identified that tasks from the “poor light and obstacles” subscale were more difficult for those younger than the median age, nonusers of mobility aids, and those not registered or registered sight impaired. Tasks from the “finding products” and “public transport” subscales were more difficult for those older than the median age, with longer duration of visual loss, users of mobility aids, and those registered severely sight impaired. Conclusions The most difficult tasks for people with RP of orienting in poor light and avoiding peripheral obstacles are relatively more difficult for those not registered as “severely sight impaired,” but are less difficult for those who use mobility aids. Mobility aids (guide dog or cane), therefore, do benefit users in their perceived ability in these particular tasks. The derived unidimensional subscales reorganize the tasks from those grouped together by goal (researcher driven) to those perceived as requiring similar skills by people with RP (patient driven) and can be used as an evidence base for orientation and mobility training protocols.

Subjective and Objective Measures of Daytime Activity and Sleep Disturbance in Retinitis Pigmentosa

“…Decreased daytime physical activity and bouts of napping can attenuate nocturnal sleep drive, and conversely sleep disturbances may lead to fatigue and daytime sleepiness, which can create a vicious cycle. The results presented here, along with those from previous studies, 23,33 highlight the importance of developing interventions for retinitis pigmentosa patients to maintain their visual functioning and thus their employability, mobility and physical activity.…”

“…Retinitis pigmentosa is a devastating retinal disease that involves progressive visual function loss and leads to increased difficulty with completing important activities of daily living, 23 with the potential to affect both daytime activity levels and sleep. More severe vision loss in retinitis pigmentosa has been previously associated with greater impairment of mobility in studies involving either self-reports or performance measures in controlled laboratory or real world settings.…”

“…31 In particular, retinitis pigmentosa subjects previously self-reported that several of the most difficult activities are related to mobility, such as orienting in poor light, avoiding peripheral obstacles, and using public transport, especially among those with longer duration of visual loss and/or more severe vision loss. 23 Difficulty with orientation and mobility may cause people with retinitis pigmentosa to restrict their activities. A previous survey administered in the Republic of Korea showed that retinitis pigmentosa patients were significantly more likely to be physically inactive than the general population.…”

Influence of Systematic Gaze Patterns in Navigation and Search Tasks with Simulated Retinitis Pigmentosa

“…It affects approximately 0.03% of the world population and is for the majority of cases not curable [4]. Although patients with RP oftentimes retain their normal visual acuity until late stages of the disease [5], the loss of peripheral vision was shown to severely limit the ability of patients to safely navigate and avoid obstacles [6,7]. However, the optic flow and judgement of direction is not affected by the decreased FoV [8,9], leading to the assumption that the decrease in navigation performance is caused mainly by a lack of obstacle awareness.…”

A novel, wearable, electronic visual aid to assist those with reduced peripheral vision

“…[16] Navigation is slower and less accurate compared to controls; outcomes that are exaggerated in reduced lighting and partially reversed by using mobility aids. [17, 18] To objectively determine how reduced peripheral vision affects functional ability, standardised tools such as ‘Assessment of Disability Related to Vision’ (ADREV) have been developed. [19] If mobility is being assessed, the ADREV obstacle course can be used in isolation.…”