Do Mild Traumatic Brain Injury Severity Sub-classification Systems Help to Identify People Who Go on to Experience Long-Term Symptoms?

Atypical symptom reporting after mild traumatic brain injury

OBJECTIVE

Early reporting of atypical symptoms following a mild traumatic brain injury (mTBI) may be an early indicator of poor prognosis. This study aimed to determine the percentage of people reporting atypical symptoms 1-month post-mTBI and explore links to recovery 12 months later in a community-dwelling mTBI sample.

METHODS

Adult participants (>16 years) who had experienced a mTBI were identified from a longitudinal incidence study (BIONIC). At 1-month post-injury, 260 participants completed the Rivermead Post-Concussion Symptoms Questionnaire (typical symptoms) plus four atypical symptom items (hemiplegia, difficulty swallowing, digestion problems and difficulties with fine motor tasks). At 12 months post-injury, 73.9% (n = 193) rated their overall recovery on a 100-point scale. An ordinal regression explored the association between atypical symptoms at 1 month and recovery at 12 months post-injury (low = 0-80, moderate = 81-99 and complete recovery = 100), whilst controlling for age, sex, rehabilitation received, ethnicity, mental and physical comorbidities and additional injuries sustained at the time of injury.

RESULTS

At 1-month post-injury <1% of participants reported hemiplegia, 5.4% difficulty swallowing, 10% digestion problems and 15.4% difficulties with fine motor tasks. The ordinal regression model revealed atypical symptoms were not significant predictors of self-rated recovery at 12 months. Older age at injury and higher typical symptoms at 1 month were independently associated with poorer recovery at 12 months, p < 0.01.

CONCLUSION

Atypical symptoms on initial presentation were not linked to global self-reported recovery at 12 months. Age at injury and typical symptoms are stronger early indicators of longer-term prognosis. Further research is needed to determine if atypical symptoms predict other outcomes following mTBI.

Diffusion and functional MRI findings and their relationship to behaviour in postconcussion syndrome: a scoping review

Postconcussion syndrome (PCS) is a term attributed to the constellation of symptoms that fail to recover after a concussion. PCS is associated with a variety of symptoms such as headaches, concentration deficits, fatigue, depression and anxiety that have an enormous impact on patients' lives. There is currently no diagnostic biomarker for PCS. There have been attempts at identifying structural and functional brain changes in patients with PCS, using diffusion tensor imaging (DTI) and functional MRI (fMRI), respectively, and relate them to specific PCS symptoms. In this scoping review, we appraised, synthesised and summarised all empirical studies that (1) investigated structural or functional brain changes in PCS using DTI or fMRI, respectively, and (2) assessed behavioural alterations in patients with PCS. We performed a literature search in MEDLINE (Ovid), Embase (Ovid) and PsycINFO (Ovid) for primary research articles published up to February 2020. We identified 8306 articles and included 45 articles that investigated the relationship between DTI and fMRI parameters and behavioural changes in patients with PCS: 20 diffusion, 20 fMRI studies and 5 papers with both modalities. Most frequently studied structures were the corpus callosum, superior longitudinal fasciculus in diffusion and the dorsolateral prefrontal cortex and default mode network in the fMRI literature. Although some white matter and fMRI changes were correlated with cognitive or neuropsychiatric symptoms, there were no consistent, converging findings on the relationship between neuroimaging abnormalities and behavioural changes which could be largely due to the complex and heterogeneous presentation of PCS. Furthermore, the heterogeneity of symptoms in PCS may preclude discovery of one biomarker for all patients. Further research should take advantage of multimodal neuroimaging to better understand the brain-behaviour relationship, with a focus on individual differences rather than on group comparisons.

Rasch analysis of the Brain Injury Screening Tool (BIST) in mild traumatic brain injury

Objective

To evaluate the psychometric properties of the Brain Injury Screening Tool (BIST) symptom scale in a sample of people with a mild Traumatic Brain Injury (mTBI) through Rasch analysis, and to obtain an interval level measurement score for potential clinical use.

Materials and methods

Data were obtained from 114 adults aged over 16 years, who had experienced at least one mTBI in the past 10 years. Participants were recruited via social media, concussion clinics and sports organisations over a 4-month period between May and September 2020. Participants were asked to compete the symptom scale of the BIST tool via an anonymous online questionnaire. Internal construct validity, dimensionality, person separation index, and differential item functioning of the BIST were examined with Rasch analysis.

Results

BIST in its original form produced a satisfactory item-trait interaction, and good reliability, but was found to be multi-dimensional. Rasch analysis of the full scale with three domains as subtests resulted in acceptable model fit (χ²(6) =3.8, p >  0.05), with good reliability (Person Separation Index = 0.84), and uni-dimensionality. Differential Item Functioning (DIF) analysis displayed no significant DIF effects for sex or age revealing that people responded consistently and similarly to the individual BIST items based on severity of symptom burden.

Conclusions

The 15-item symptom scale of the BIST tool is a psychometrically sound measure of symptom burden following mTBI. The findings provide support for use of both total and sub scale scores for clinical use. Ordinal to interval score conversions are recommended for use when using the scores for research purposes in mTBI.

Sensitivity to Noise Following a Mild Traumatic Brain Injury: A Longitudinal Study

OBJECTIVE

To describe changes in the prevalence and clinical correlates of noise sensitivity (NS) in mild traumatic brain injury (mTBI) across a 12-month period and to determine whether NS at an early stage of recovery has predictive value for later postconcussive symptoms.

SETTING

A mixed urban and rural region of New Zealand.

PARTICIPANTS

Data for 341 adults (201 males, 140 females; age range from 16 to 91 years) were extracted from a 1-year TBI incidence, and outcomes study was conducted in New Zealand.

DESIGN

Secondary analysis of data from a community-based, longitudinal population study of an mTBI incidence cohort collected within 1 week of injury (baseline) and at 1, 6, and 12 months postinjury.

MAIN MEASURES

Measures at baseline (within 2 weeks of the injury) and 1, 6, and 12 months included the Rivermead Post-concussion Symptoms Questionnaire and its NS item, the Hospital Depression and Anxiety Scale, and the computerized CNS-Vital Signs neurocognitive test.

RESULTS

NS progressively declined postinjury, from 45% at baseline to 28% at 12 months. In turn, NS showed itself as a significant predictor of future postconcussive symptoms.

CONCLUSION

Taken together with previous research, the findings of the current study indicate that NS may have clinical utility in flagging vulnerability to persistent postconcussive symptoms.