*Strengths and Limitations*

A mixed method study enables new insights to be gained concerning a heterogeneous group such as persons with STBI. The lack of depth of the information that can be gained through surveys can be compensated for through interviews. Our results show how useful it is to combine qualitative and quantitative methods whereby one gains another level of understanding where, metaphorically speaking, "one plus one become three". It is important to gain this "insider" perspective, using qualitative data and being able to understand "what it is like," realizing that both vulnerability and well-being can co-exist after STBI, thereby gaining a wider perspective [67]. In an earlier study, it was reported that the evaluation of the outcome of rehabilitation requires both subjective and objective outcome measures. In our study, well-being as a subjective outcome can be described due to adaptation to the new situation and personal factors [39].

The strengths of this study are that it was a prospective cohort study comprising a near-total regional cohort population over a period of two years of persons of working age with STBI admitted to a neuro-trauma centre. The first author (M.S.) investigated all the registered cases at 1-year and 7-year follow-up and ensured that data were precisely and completely documented, minimising the amount of missing data and ensuring it was possible for most persons to be included. Exclusion at baseline was persons who did not survive after 3 weeks. The interviews were conducted by the last author (B.-I.S.) together with the first author (M.S.), mostly in the homes of the injured persons, which represented a safe and well-known environment. The first author was well-known to the participants, which helped to make the interview situation comfortable. There was a pre-understanding among the authors, i.e., medical knowledge of STBI rehabilitation (M.S., B.-M.S.), but the last author (B.-I.S.) was unaware of the illness history of each person, thereby limiting the risk for bias.

One limitation of the study was that it was not possible to follow up on all survivors. This study included patients from a near-total regional cohort population (*n* = 37) of STBI 2010–2011 from the earlier Probrain study, and at follow-up, there were 28 survivors. A total of 21 of these answered questionnaires, which was a rather small number for statistical analyses. However, they all participated in interviews, which was then assessed as a relatively large number. With the mixed method approach using both quantitative

and qualitative, the number of participants was considered sufficient. Since the age of the participants may reflect the inclusion criteria of persons of working–age, this could probably explain the results of a good recovery. However, the heterogeneity of the age (27–70 years old) of the participants made it difficult to draw any conclusions on differences due to specific age groups.

#### **5. Conclusions**

The life of a person who has suffered STBI is still affected to a lesser or greater degree several years after injury due to acceptance of a recovered or changed life situation. Further studies are needed on how the health and well-being of all persons with STBI can be improved from a long-term perspective.

**Author Contributions:** The three authors (M.S., B.-M.S., B.-I.S.) designed the study. The first author (M.S.) was responsible for the surveys. Two of the authors were present during the interviews (M.S., B.-I.S.) and one (B.-I.S.) performed the interviews. All three participated in the analysis. The first author (M.S.) was the main writer of the script, with contributions being made by B.-M.S. and B.-I.S. throughout the process. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by Region Västerbotten, the Swedish Association for Survivors of Polio, Accident and Injury, and the Swedish Brain Foundation.

**Institutional Review Board Statement:** This study was approved by the Ethical Review Board, Umeå, Sweden (No. 2016/444-31).

**Informed Consent Statement:** Written informed consent was obtained from the participants who were informed they were free to withdraw from the study at any time. There were no withdrawals.

**Data Availability Statement:** The datasets generated and/or analysed in this study are not publicly available as the Ethical Review Board has not approved the public availability of these data.

**Acknowledgments:** The authors would like to thank the participating persons in this study.

**Conflicts of Interest:** The authors declare no conflict of interests.

#### **References**

