Factors perpetuating functional cognitive symptoms after mild traumatic brain injury

ABSTRACT

Introduction

Self-reported memory difficulties (forgetting familiar names, misplacing objects) often persist long after a mild traumatic brain injury (mTBI), despite normal neuropsychological test performance. This clinical presentation may be a manifestation of a functional cognitive disorder (FCD). Several mechanisms underlying FCD have been proposed, including metacognitive impairment, memory perfectionism, and misdirected attention, as well as depression or anxiety-related explanations. This study aims to explore these candidate perpetuating factors in mTBI, to advance our understanding of why memory symptoms frequently persist following mTBI.

Methods

A cross-sectional study of 67 adults (n = 39 with mTBI mean = 25 months ago and n = 28 healthy controls). Participants completed standardized questionnaires (including the Functional Memory Disorder Inventory), a metacognitive task (to quantify discrepancies between their trial-by-trial accuracy and confidence), and a brief neuropsychological test battery. We assessed candidate mechanisms in two ways: (1) between-groups, comparing participants with mTBI to healthy controls, and (2) within-group, examining their associations with functional memory symptom severity (FMDI) in the mTBI group.

Results

Participants with mTBI performed similarly to controls on objective measures of memory ability but reported experiencing much more frequent memory lapses in daily life. Contrary to expectations, metacognitive efficiency did not differentiate the mTBI and control groups and was not associated with functional memory symptoms. Memory perfectionism was strongly associated with greater functional memory symptoms among participants with mTBI but did not differ between groups when accounting for age. Depression and checking behaviors produced consistent results across between-groups and within-group analyses: these factors were greater in the mTBI group compared to the control group and were associated with greater functional memory symptoms within the mTBI group.

Conclusions

This study highlights promising (e.g., depression, checking behaviors) and unlikely (e.g., metacognitive impairment) mechanisms underlying functional memory symptoms after mTBI, to guide future research and treatment.

KEYWORDS:

• Mild traumatic brain injury
• functional cognitive disorder
• metacognition
• memory
• safety-behaviors
• functional neurological disorder

Acknowledgments

We thank the GF Strong Adult Concussion Service and Fraser Health Concussion Clinic for their assistance with recruitment of participants with mTBI. We also thank the Coping with Neurological Symptoms (CNS) Lab members for their help with logistics, recruiting, and neuropsychological test administration.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest with respect to the research, authorship, and/or publication of this article.

Data availability statement

The data that support the findings of this study are available from the corresponding author, N.D.S., upon reasonable request.

Additional information

Funding

N.D.S received salary support from the Michael Smith Foundation for Health Research and R.M.T. was supported by a Michael Smith Foundation for Health Research Scholar award. These funders played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.