Optimising screening for cognitive dysfunction in bipolar disorder: validation and evaluation of objective and subjective tools

Jensen JH, Støttrup MM, Nayberg E, Knorr U, Ullum U, Purdon SE, Kessing LV, Miskowiak LV    

Journal of Affective Disorders (in press)

Abstract

Introduction: Cognitive impairment is common in bipolar disorder and contributes to socio-occupational difficulties. The objective was to validate and evaluate instruments to screen for and monitor cognitive impairments, and improve the understanding of the association between cognitive measures and socio-occupational capacity.

Methods: Patients with bipolar disorder in partial or full remission (n=84) and healthy controls (n=68) were assessed with the Screen for Cognitive Impairment in Psychiatry (SCIP), Cognitive Complaints in Bipolar Disorder Rating Scale (COBRA), and established neuropsychological tests and subjective rating scales. Socio-occupational function and affective symptoms were evaluated with the Functional Assessment Short Test, and the Hamilton Depression Rating Scale 17-items and Young Mania Rating Scale, respectively. Concurrent validity of the SCIP and COBRA were assessed by correlation with established objective and subjective cognitive measures, and decision validity was determined with Receiver-Operating-Characteristic analyses. Correlations and linear regression analyses were conducted to determine the associations between objective and subjective cognitive impairment, and socio-occupational difficulties.

Results: The SCIP and COBRA correlated strongly with established objective and subjective cognitive measures, respectively. The SCIP yielded higher sensitivity and specificity for detection of cognitive dysfunction than the COBRA or a combined SCIP-COBRA measure. Correlations between objective and subjective cognitive impairment were weak but both were associated with socio-occupational difficulties.

Limitations: Influence of ageing was not investigated.

Conclusions: The SCIP and COBRA are valid for detection of objective and subjective cognitive impairment in bipolar disorder. Screening for cognitive dysfunction should be conducted with an objective measure like the SCIP.