Development and initial validation of a screening tool for visual ability/performance of people with polyhandicap.

ABSTRACT

BACKGROUND: Visual impairments are common in people with polyhandicap although they are poorly assessed. However, evaluation of the visual abilities of these people is critical to determining treatment for impairments. OBJECTIVES: To develop and validate an easy-to-use visual-behavioural scale for assessing the visual abilities of people with polyhandicap. METHODS: The development of the Visual Assessment for People with Polyhandicap (VA-PLH) involved 2 steps: i) construction of the scale and ii) field validation. Participant selection criteria were aged > 3 years, age at onset of cerebral lesion < 3 years, a combination of motor impairment and profound intellectual impairment associated with restricted mobility (Gross Motor Function Classification System levels [GMFCS] III, IV or V), and everyday life dependence (Functional Independency Measure [FIM] <55). Vision assessment by both an orthoptist and an ophthalmologist was the reference against which were analysed the items of the scale completed by local health care workers. Acceptability, validity, and reliability were analysed. RESULTS: Amongst the 232 participants included, 217 had a complete assessment, and 33% were < 18 years of age. Ocular abnormalities were reported in 83% of participants. Visual ability was altered or insufficient in 60% of participants. The final version of the VA-PLH included 3 items related to visual reaction (Area Under Curve Receiver Operating Characteristic = 0.83). Participants were considered at-risk if they had at ≥ 1 of 3 signs present (sensitivity 83% and specificity 73%). The scale's reliability was satisfactory CONCLUSION: The VA-PLH scale provides an easy-to-use, reliable and valid measure of visual status for people with polyhandicap and may be used both in clinical practice and clinical research. In addition, this study provides an overview of the diversity of visual impairments in a large population of people with polyhandicap, showing that most experience visual challenges.