Construct and criterion validity of the CogState cognitive test battery in patients with stable schizophrenia

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Construct and criterion validity of the CogState
cognitive test battery in patients with stable
schizophrenia
Robert H Pietrzak, Dept of Psychiatry Yale
University James Olver, Trevor Norman
Danijela Piskulic, Dept Psychiatry University of
Melbourne Paul Maruff, CogState Ltd Peter J.
Snyder, Brown University
Introduction The aim of the current study was to
investigate the criterion and construct validity
of the CogState Schizophrenia Battery using the
tasks recommended by the MATRICS group as a
benchmark. First, we investigated the
sensitivity of the CogState tasks in assessing
cognitive impairment in schizophrenia and
compared this to the sensitivity of the tests
recommended by the MATRICS group in the same
patients. We then determined the extent to
which performance on tests of the same cognitive
domain from the different test batteries was
associated in the group of patients and in
healthy controls. Finally, we determined the
extent to which composite measures of performance
from both batteries were associated with
functional abilities in patients with
schizophrenia.
Table 1 Demographic characteristics of patients
and controls
Fig 1 Criterion validity of MATRICS and
CogState Schizophrenia Batteries in chronic
schizophrenia. Magnitude of impairment (d)
relative to control group.
Patients Schizophrenia group Cognitive test data
were collected from 121 patients who had a
primary diagnosis (DSM-IV) of schizophrenia or
schizoaffective disorder (DSM-IV American
Psychiatric Association, 2000). Patients were
recruited from outpatient clinics in academic and
research departments in North America, Australia,
and the United Kingdom. They were all free from
an acute severe exacerbation of psychosis or
clinically significant depressive symptoms for at
least three months prior to study. All patients
had been receiving treatment with the same oral
antipsychotic treatment for at least three months
prior to enrollment. All patients had a Clinical
Global Impression of Severity of Illness (CGI-S)
score of less than 4 and a Positive and Negative
Syndrome Scale (PANSS) total score of greater
than 55. No patient had received any trial
medication at the time of the assessment. All
patients were considered to be stable and had
been treated with a constant dose of a
second-generation atypical antipsychotic
medication (e.g., risperidone, olanzapine,
clozapine) for two months prior to and during the
study period. No patient had been hospitalized
or received acute intervention for a psychiatric
condition within four months of commencement of
the study, and none had received
electroconvulsive therapy (ECT) within the
preceding two years (81 had never received ECT).
All patients spoke English as their first
language with at least an 8th-grade education and
all had normal or corrected to normal visual
function (Table 1). Control group 120 healthy
adults were recruited from among unemployed
individuals who were attending government work
skills training programs in the United Kingdom
and Australia. They were matched as a group to
the patient group by age, male/female ratio,
education, and estimated premorbid IQ. None of
these individuals met criteria for any DSM-IV
Axis I psychiatric or substance use disorder.
None of the control participants were receiving
psychoactive medication at the time of
assessment. General exclusion criteria Exclusion
criteria for all subjects in both groups
included any current or past histories of
neurological disorders (other than schizophrenia
for the patient group), including head injury, or
alcohol or drug use disorders. No subject had
evidence of focal brain abnormality on head
computed tomography (CT) scan. Assessment All
patients and controls were assessed using the
tests listed in Table 2 in a single session. The
order of cognitive assessments was as given in
Table 2. A measure of functional status,
University of California at San Diego (UCSD)
Performance-Based Skills Assessment was given on
the day after cognitive assessment.
Table 2 Description of the cognitive tasks used
in the conventional and computerized batteries
Table 3 Inter-correlations between cognitive
tasks from the CogState and MATRICS test
batteries that measure the same cognitive domain.
Test Cognitive domain Outcome measure Abbreviation
Conventional tests
Trail Making Test Part A Speed of processing Time to complete TMT-A
Brief assessment of cognition in schizophrenia (BACS) symbol coding test Speed of processing Total number of correct responses BACS-Co
Category Fluency Speed of Processing Number of words generated in 60 secs Cat Flu
Hopkins Verbal Learning Test-Revised Verbal Learning Words learned across three learning trials HVLT
Wechsler Memory Scale III spatial span Working memory Non Verbal Sum of forward and backward raw scores WMS-span
Letter number span Working memory Verbal Number of correct trials Let Num Span
Neuropsychological assessment Battery Mazes Reasoning and Problem Solving Total raw score NAB-Maze
Brief Visual Memory Test Revised Visual Learning Total score over three learning trials BVMT
Mayer_Salovey_Caruso Emotional intelligence Test managing emotions subtest Social Cognition Branch score MSCEIT
Continuous Performance Task Identical Pairs version Attention/ Vigilance Mean d value across 2,3 and 4 digit conditions CPT-IP
Composite score General cognitive function Composite standardized score Conventional-composite
Computer tests
Detection Task Speed of Processing Average speed of correct responses Detect
Identification Task Attention/ Vigilance Average speed of correct responses Ident
One Back Memory Task Working memory Proportion of correct responses One-back
Two Back Memory Task Working memory Proportion of correct responses Two-Back
Visual Learning Task Visual Learning Proportion of correct responses Vis-Learn
International Shopping List Task Verbal Learning Number of words recalled across three learning trials ISLT-words
Groton Maze Learning Task Reasoning and Problem Solving Number of errors made across five learning trials GMLT
Social Emotional Cognition Task Social Cognition Proportion of correct responses SECT
Composite score General cognitive function Composite standardized score Computer composite
Domain Correlation Controls Schizophrenia
Speed of Processing TMT-A vs Ident 0.57 0.56
Speed of Processing BACS-Co vs Ident 0.45 0.76
Speed of Processing Cat-Flu vs Ident 0.59 0.79
Attention/ Vigilance CPT-IP vs Detect 0.46 0.57
Working memory Let Num Span vs One-back 0.61 0.75
Working memory Let Num Span vs Two-Back 0.75 0.73
Working memory Spatial Span vs One-Back 0.43 0.56
Working memory Spatial Span vs Two-Back 0.51 0.69
Verbal Learning HVLT vs ISLT 0.84 0.78
Visual Learning BVMT vs Vis-Learn 0.63 0.76
Reasoning Problem Solving NAB mazes vs GMLT 0.56 0.56
Social Cognition MSCEIT vs SECT 0.45 0.59
Composite Conventional vs computer 0.78 0.83

• plt0.05 plt0.01
• Functional measure and cognitive performance
• The group mean score among the schizophrenic
  patients who completed the UPSA was 80.6 (SD
  16.2). The correlation between the UPSA total
  score and the composite score from the
  conventional battery was 0.79 (plt0.001, n98).
  The correlation between the UPSA total score and
  the composite score from the computerized battery
  was 0.76 (plt0.001, n93).

Conclusion The CogState schizophrenia battery has
equivalent sensitivity to cognitive impairment in
schizophrenia, has good validity for the
cognitive constructs identified as important by
the MATRICS group and is strongly associated with
functional abilities in schizophrenia.