Data collection

Standardized data forms or tablets are used to collect data with paper back up available in case of tablet failure. Participants will fill in all questionnaires in a separate room. To ensure that appropriate help and guidance can be given when needed, one of the researchers will present. Meanwhile, communication partners who communicate with participants on a daily or near-daily basis (e.g., spouse) are often a key to getting accurate results. Therefore, accompanying adults are also invited to join the study and contribute to the data.

To minimize data-entry errors, the questionnaires have inbuilt check-and-skip rules. And the questionnaires were tested on four participants beforehand, who found the questions understandable and possible to complete in 30–45 min. For participants who withdraw from the trial, any data collected up to the withdrawal date will be retained and included in the analyses. Data are collected at the local field prior to randomization (baseline T0), after 12 months (post intervention T1) and 20 months after baseline (follow-up T2). A SPIRIT flow diagram illustrates the data collection in the intervention group and control group (Table 2) [38].

Schedule of enrollment, interventions, and assessments

Abbreviations: T, treatment group; C, control group; HHIE-S, Hearing Handicap for the Elderly-Screening Version; IOI-HA, The International Outcome Inventory for Hearing Aids; SF-12, Short Form 12 Health Survey; EQ-5D, EuroQoL 5-Dimension; ADLs, activities of daily living; IADLS, instrumental activities of daily living; MMSE, Mini-Mental State Examination; CES-D, Center for Epidemiologic Studies-Depression; LSNS, Lubben Social Network Scale