CLN3 disease manifests in early school age with vision loss, followed by seizures and progressive psychomotor regression. Monitoring cognitive decline is crucial to evaluate efficacy of new therapies. However, standard neuropsychological tests lack of test batteries suitable for individuals with visual impairments. The Vineland Adaptive Behavior Scale (Vineland-3) is a psychometric tool that evaluates an individual’s adaptive functioning via standardized caregiver interviews and is therefore applicable in visually impaired patients.
14 CLN3 patients (ages 8-17 years, male n=4, female n=10) were tested using the Vineland-3 with a total of 27 assessments in 1-3 follow-up exams per patient. Disease progression was categorized using an established CLN3 disease staging system which categorises four disease stages according to the onset of vision loss, epilepsy, and motor decline regardless of cognitive function levels. The analysis focused on three primary domains - communication, socialization, and daily living skills - along with their respective subdomains and the overall adaptive behavior composite score.
The mean score for the communication domain was 63.4 in patients at disease stage 1 (n=6), 40.9 at stage 2 (n=8), and 30 at stage 3 (n=1). Similarly, the mean score for the socialization domain declined from 81.3 (stage 1) to 59.7 (stage 2) and 63 (stage 3). The daily living domain showed the most significant decline, with mean scores of 69.6 (stage 1), 46.3 (stage 2), and 26 (stage 3). Analysis of the three subdomains within each main domain, as well as the global adaptive behavior composite score (mean scores: 67.2 for stage 1, 44.4 for stage 2, and 34 for stage 3), also revealed a consistent decline across all three disease stages.
In conclusion, application of the Vineland-3 allows to assess cognitive function of CLN3 patients regardless of their progressive vision loss and supports the categorization of patients into different disease stages.