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Background Following a concussion, approximately 15% of individuals experience persistent symptoms that can lead to functional deficits. However, underlying symptom-clusters that persist beyond 12 months have not been adequately characterized, and their relevance to functional deficits are unclear. The aim of this study was to characterize the underlying clusters of prolonged post-concussive symptoms lasting more than 12 months, and to investigate their association with functional impairments. Methods Although hierarchical clustering is ideally suited in evaluating subjective symptom severities, it has not been applied to the Rivermead Post-Concussion Questionnaire (RPQ). The RPQ and functional impairments questions were administered via a smartphone application to 445 individuals who self-reported prolonged post-concussive symptoms. Symptom-clusters were obtained using agglomerative hierarchical clustering, and their association with functional deficits were investigated with sensitivity analyses, and corrected for multiple comparisons. Results Five symptom-clusters were identified: headache-related, sensitivity to light and sound, cognitive, mood-related, and sleep-fatigue. Individuals with more severe RPQ symptoms were more likely to report functional deficits ( p < 0.0001). Whereas the headache and sensitivity clusters were associated with at most one impairment, at-least-mild sleeping difficulties and fatigue were associated with four, and moderate-to-severe cognitive difficulties with five (all p < 0.01). Conclusions Symptom-clusters may be clinically useful for functional outcome stratification for targeted rehabilitation therapies. Further studies are required to replicate these findings in other cohorts and questionnaires, and to ascertain the effects of symptomatic intervention on functional outcomes.

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BackgroundThe Clinical Dementia Rating (CDR) and Mini-Mental State Examination (MMSE) are useful screening tools for mild cognitive impairment (MCI). However, these tests require qualified in-person supervision and the CDR can take up to 60 min to complete. We developed a digital cognitive screening test (M-CogScore) that can be completed remotely in under 5 min without supervision. We set out to validate M-CogScore in head-to-head comparisons with CDR and MMSE.MethodsTo ascertain the validity of the M-CogScore, we enrolled participants as healthy controls or impaired cognition, matched for age, sex, and education. Participants completed the 30-item paper MMSE Second Edition Standard Version (MMSE-2), paper CDR, and smartphone-based M-CogScore. The digital M-CogScore test is based on time-normalised scores from smartphone-adapted Stroop (M-Stroop), digit-symbols (M-Symbols), and delayed recall tests (M-Memory). We used Spearman's correlation coefficient to determine the convergent validity between M-CogScore and the 30-item MMSE-2, and non-parametric tests to determine its discriminative validity with a CDR label of normal (CDR 0) or impaired cognition (CDR 0.5 or 1). M-CogScore was further compared to MMSE-2 using area under the receiver operating characteristic curves (AUC) with corresponding optimal cut-offs.Results72 participants completed all three tests. The M-CogScore correlated with both MMSE-2 (rho = 0.54, p &lt; 0.0001) and impaired cognition on CDR (Mann Whitney U = 187, p &lt; 0.001). M-CogScore achieved an AUC of 0.85 (95% bootstrapped CI [0.80, 0.91]), when differentiating between normal and impaired cognition, compared to an AUC of 0.78 [0.72, 0.84] for MMSE-2 (p = 0.21).ConclusionDigital screening tests such as M-CogScore are desirable to aid in rapid and remote clinical cognitive evaluations. M-CogScore was significantly correlated with established cognitive tests, including CDR and MMSE-2. M-CogScore can be taken remotely without supervision, is automatically scored, has less of a ceiling effect than the MMSE-2, and takes significantly less time to complete.

BackgroundThe Clinical Dementia Rating (CDR) and Mini-Mental State Examination (MMSE) are useful screening tools for mild cognitive impairment (MCI). However, these tests require qualified in-person supervision and take up to 60 or 15 minutes to complete respectively. We have developed a digital cognitive screening test (M-CogScore) that can be completed remotely in under 5 minutes without supervision. We set out to validate M-CogScore in head-to-head comparisons with CDR and MMSE. MethodsTo ascertain the validity of the M-CogScore, we enrolled participants as healthy controls or impaired cognition matched for age, sex, and education. Participants completed the 30-item paper MMSE Second Edition Standard Version (MMSE-2-SV), paper CDR, and smartphone-based M-CogScore. The digital M-CogScore test is based on time-normalised scores from smartphone adapted stroop (M-Stroop), digit-symbols (M-Symbols), and delayed recall tests (M-Memory). We used Pearson’s correlation coefficient to determine the convergent validity between M-CogScore and the 30-item MMSE-2, and non-parametric tests to compare M-CogScore with a CDR diagnosis of impaired cognition (CDR 0.5 or 1). M-CogScore was compared to MMSE-2-SV using area under the receiver operating characteristic curves (AUC) with corresponding optimal cut-offs. Results72 participants completed all three tests. The M-CogScore correlated with both MMSE-2 (r=0.66, p<0.0001) and impaired cognition on CDR (Mann Whitney U 187, p<0.001). M-CogScore achieved an AUC of 0.85 (95% bootstrapped CI [0.80, 0.91]) when differentiating between normal and impaired cognition, compared to an AUC of 0.78 [0.72, 0.84] for the MMSE-2-SV (p=0.21) ConclusionM-CogScore was significantly correlated with established cognitive tests including CDR and MMSE-2-SV. M-CogScore can be taken remotely without supervision, is automatically scored, has less of a ceiling effect than the MMSE, and takes significantly less time to complete. Digital screening tests such as M-CogScore are desirable to aid in rapid and remote clinical cognitive evaluations.

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