2.3.2. Quantitative Data Collection and Analysis

In this study, quantitative data were collected through a questionnaire containing background questions and the following instruments: GOSE for functional outcome [6], HADS [47] for emotional health, EQ-VAS [48] as a self-report of overall perceived health, and MFS for mental fatigue [49]. All instruments had closed-ended questions and were distributed at 1-year and 7-year follow-up except MFS. The questionnaires were sent by mail in conjunction with interviews.

#### Instruments

#### Glasgow Outcome Scale-Extended, GOSE

GOSE evaluates functional outcome after STBI with regard to 8 categories, with a span from "death" (score 1) to "upper good recovery" (score 8). The categories were independence at home, shopping, work, social activities, leisure activities, family, friendship or other problems after TBI. In this study, we used good recovery (GOSE 7–8), moderate disability (GOSE 5–6) and severe disability (GOSE 3–4). The GOSE has good interrater reliability and validity [50].

#### Hospital Anxiety and Depression Scale, HADS

HADS is an established screening tool for anxiety and depression and has previously been used for patients with STBI [51]. It consists of 14 items organised as 7 items in 2 subscales, HADS-depression (HADS-D) and HADS-anxiety (HADS-A). Both subscales were assessed on a 4-point Likert scale (range 0–3), with the sum of each subscale as the total score (range 0–21). Cut-offs were 8 or higher for both subscales and indicate mild to severe depression and anxiety. The HADS has acceptable reliability, sensitivity and specificity in various populations [52].

## Euro-QoL-Visual Analogue Scale, EQ-VAS

The EQ-VAS [41] measures self-reported overall health on a vertical visual analogue 0–100 scale, where the end points were labelled with 100 denoting the best imaginable health and zero as the worst. The EQ-VAS can be used as a quantitative measure of health outcome and is also used in studies of TBI patients (15,16). The participants were asked to mark their health status on the VAS scale. This instrument was validated and has good reliability [53].
