# Development of the Common Cognitive Complaints after Concussion (C4) questionnaire: a treatment-planning tool for military service members and veterans with mild traumatic brain injury

## TL;DR

This paper describes the development of a questionnaire to help personalize cognitive rehabilitation for military personnel and veterans with mild traumatic brain injury.

## Contribution

The C4 questionnaire is a new tool for identifying activity-based treatment targets in mTBI rehabilitation.

## Key findings

- The C4 questionnaire includes 22 activity-based items validated by experts and clinicians.
- The C4 effectively captures functional impairments specific to mTBI and is useful for personalizing treatment.
- The C4 was tested in a trial and found to be distinct from symptoms of orthopedic injury.

## Abstract

To develop an activity-focused self-report tool to guide selection of treatment targets in cognitive rehabilitation for adults with mild traumatic brain injury (mTBI).

Military and veteran treatment facilities.

Twenty-one service members and 32 veterans with a history of mTBI; 25 veterans with orthopedic injury (OI).

Clinical tool development.

Common Cognitive Complaints after Concussion (C4) questionnaire.

We reviewed measures used in mTBI research or clinic, to identify items that could be used for selecting activity-level therapy targets as part of a treatment planning tool. To establish face and content validity, an initial item pool was reviewed by five speech-language pathology or occupational therapy mTBI experts who selected items relevant to their clinical practice, gave feedback on item wording, and suggested additional items. The result was a questionnaire with 22 activity-based items and one bias-check item. The C4 was then used in a feasibility mTBI treatment trial to identify treatment targets, and clinicians provided feedback on its utility. The C4 was also administered to an OI group to evaluate the distinctiveness of the items to mTBI symptoms.

The C4 adequately captured activity-level functional impairments common to mTBI, and clinicians endorsed its utility as a useful tool to personalize treatment targets.