Calibration and cross-validation of MCCB and CogState in schizophrenia

Cognitive impairment associated with schizophrenia is a key predictor of functional outcomes. The FDA-accepted MATRICS Consensus Cognitive Battery (MCCB) is held to be the gold standard measure but there are concerns about its ease of administration, reliance on language causing problems with translation and possible practice effects. The CogState Schizophrenia Battery (SB) is suggested as a non-language-based alternative but there is no substantial, independent comparison.

The objective of this study was to assess the reliability and validity of these two assessment batteries.

One hundred forty-three participants with DSM-IV schizophrenia and schizoaffective disorder were recruited into three similar studies. Each study administered MCCB and SB tests on consecutive days (baseline 1 and 2) and follow-up 3-4 weeks later.

Batteries' test-retest reliability was similar: SB composites correlated r = 0.66-0.78 between baselines, MCCB domains r = 0.69-0.90. Baseline 2 and follow-up SB composites correlated r = 0.65-0.80 and MCCB domains r = 0.62-0.87. MCCB tasks' practice effects (Glass' ∆ = 0.02-0.46) exceeded SB's (Glass' ∆ = 0.02-0.34). While the batteries' total scores correlated strongly (r = 0.79-0.82), apparently equivalent cognitive domains on each battery (e.g. psychomotor-attention) correlated r = 0.22-0.60, indicating substantial differences between some supposed counterparts.

Clinical trials using either battery would benefit from initial practice sessions to ameliorate practice effects but the SB may be more suitable to measure change in the absence of repeated baselines. The MCCB domains' better correlations with social skills performance suggest that it may have an advantage for measuring cognition in relation to functional outcome.