Unique Functional Profiles in Deafblindness: Evidence From a Comparative Analysis of ICF Core Sets.

Objective: This study examined whether the functional implications of deafblindness can be understood as the simple sum of vision loss and hearing loss or whether deafblindness constitutes a distinct sensory disability. By comparing the comprehensive ICF Core Sets for vision loss, hearing loss, and deafblindness, the study aimed to determine the extent to which deafblindness reflects unique patterns of functioning beyond additive single sensory difficulties. Method: A secondary comparative analysis was conducted using all items from the three Core Sets that were classified according to the four ICF components (body functions, body structures, activities and participation, and environmental factors). Items were merged into a single dataset and coded for their presence in each condition. A systematic item-level comparison was performed to identify categories that were common to all three Core Sets, shared by two, or unique to a single sensory condition. No weighting was applied; all items were treated equally. The final output grouped items, reflecting different patterns of overlap and uniqueness. Results: The Core Sets contained 98 items for vision loss, 118 for hearing loss, and 219 for deafblindness. A total of 435 distinct categories were identified. Of these, 53 items appeared in all three conditions. Overlap showed 27 items shared between vision loss and deafblindness, 34 between hearing loss and deafblindness, and 11 between vision and hearing loss. Unique items were most pronounced in the deafblindness Core Set (n = 105), followed by hearing loss (n = 20) and vision loss (n = 7), indicating a substantial condition-specific functional profile for deafblindness. Conclusion: The results demonstrate that deafblindness is not merely the additive coexistence of vision and hearing loss but reflects a distinct and more complex functional profile. These findings support the need for condition-specific clinical approaches, policies, and assessment frameworks tailored to the unique demands of deafblindness.