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.

Assessment of subjective and objective cognitive function in bipolar disorder: Correlations, predictors and the relation to psychosocial function

Demant KM, Vinberg M, Kessing LV, Miskowiak KW

Psychiatry Res. 2015 Jun 3. pii: S0165-1781(15)00291-7.

Abstract

Cognitive dysfunction is prevalent in bipolar disorder (BD). However, the evidence regarding the association between subjective cognitive complaints, objective cognitive performance and psychosocial function is sparse and inconsistent. Seventy seven patients with bipolar disorder who presented cognitive complaints underwent assessment of objective and subjective cognitive function and psychosocial functioning as part of their participation in two clinical trials. We investigated the association between global and domain-specific objective and subjective cognitive function and between global cognitive function and psychosocial function. We also identified clinical variables that predicted objective and subjective cognitive function and psychosocial functioning. There was a correlation between global subjective and objective measures of cognitive dysfunction but not within the individual cognitive domains. However, the correlation was weak, suggesting that cognitive complaints are not an assay of cognition per se. Self-rated psychosocial difficulties were associated with subjective (but not objective) cognitive impairment and both subjective cognitive and psychosocial difficulties were predicted by depressive symptoms. Our findings indicate that adequate assessment of cognition in the clinical treatment of BD and in drug trials targeting cognition requires implementation of not only subjective measures but also of objective neuropsychological tests.

Is there an association between subjective and objective measures of cognitive function in patients with affective disorders?

Svendsen AM, Kessing LV, Munkholm K, Vinberg M, Miskowiak KW

Nord J Psychiatry. 2012 Sep;66(4):248-53.

Abstract

BACKGROUND: Patients with affective disorders experience cognitive dysfunction in addition to their affective symptoms. The relationship between subjectively experienced and objectively measured cognitive function is controversial with several studies reporting no correlation between subjective and objective deficits.

AIMS: To investigate whether there is a correlation between subjectively reported and objectively measured cognitive function in patients with affective disorders, and whether subjective complaints predict objectively measured dysfunction.

METHODS: The study included 45 participants; 15 with bipolar disorder (BD), 15 with unipolar disorder (UD) and 15 healthy individuals. Participants’ subjectively experienced cognitive function and objective cognitive function were assessed with the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ) and the Screen for Cognitive Impairment in Psychiatry (SCIP), respectively. Patients were rated for affective symptoms with Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS).

RESULTS: Patients demonstrated subjective and objective cognitive dysfunction relative to controls (P-values ≤ 0.01) but there were no differences between patient groups (P > 0.1). We found no correlation between subjectively experienced and objectively measured cognitive dysfunction in BD (P = 0.7), and a non-significant trend towards a correlation in UD (P = 0.06), which disappeared when controlling for gender (P = 0.1).

CONCLUSION: Our results suggest that it is not necessarily patients who have cognitive complaints that are most impaired. If confirmed in a larger sample, our findings suggest that neuropsychological assessment is warranted to elucidate the potential role of cognitive dysfunction in patients’ everyday lives and to inform treatment strategies targeting these difficulties.