Persistent post-concussive symptoms: A model of predisposing, precipitating, and perpetuating factors.

While the majority of individuals make full recovery within a short period following mild traumatic brain injury (mTBI), some continue to experience a more chronic course of symptoms termed persistent post-concussive symptoms (PPCS). Previous models and conceptualizations of PPCS have typically not differentiated the time at which factors present across the injury timeline spectrum or have considered a limited array of contributory factors. In the current review, PPCS are examined within the predisposing, precipitating, and perpetuating (PPP) model, which has been applied to explain other syndromes resulting in a clear framework to explain, disseminate, and further research the specified condition. Previous PPCS models are reviewed and integrated into this comprehensive model, as well. To do so, a literature review was completed which included previous PPP models applied to other conditions, other PPCS models, and more recent findings of factors related to PPCS. This new iteration and application of the PPP model more clearly, completely, and validly identifies contributing factors to PPCS. Future prevention, early identification, clearer questions for future research, and treatment of PPCS is possible with clarity provided by this model.

Embedded performance validity testing in neuropsychological assessment: Potential clinical tools.

The article aims to suggest clinically-useful tools in neuropsychological assessment for efficient use of embedded measures of performance validity. To accomplish this, we integrated available validity-related and statistical research from the literature, consensus statements, and survey-based data from practicing neuropsychologists. We provide recommendations for use of 1) Cutoffs for embedded performance validity tests including Reliable Digit Span, California Verbal Learning Test (Second Edition) Forced Choice Recognition, Rey-Osterrieth Complex Figure Test Combination Score, Wisconsin Card Sorting Test Failure to Maintain Set, and the Finger Tapping Test; 2) Selecting number of performance validity measures to administer in an assessment; and 3) Hypothetical clinical decision-making models for use of performance validity testing in a neuropsychological assessment collectively considering behavior, patient reporting, and data indicating invalid or noncredible performance. Performance validity testing helps inform the clinician about an individual's general approach to tasks: response to failure, task engagement and persistence, compliance with task demands. Data-driven clinical suggestions provide a resource to clinicians and to instigate conversation within the field to make more uniform, testable decisions to further the discussion, and guide future research in this area.