Study designs of evaluations included in the review
Studies without a control group, or with a poor report of performance data (no or only partial indication of means and standard deviations of test scores) were excluded. Studies without external measures of outcome were also excluded.
Specific interventions included in the review
Computer-based and non-computer-based attention training programmes were eligible. In the included studies, training programmes had been incorporated into standard in-patient or out-patient programmes. Attention training was compared with the following control therapies: no specific treatment; individual vocational therapy; creativity training; communication training; no attention training but otherwise the same treatment programme; graphics-based computer games; and viewing of documentaries. The training lasted from 3 to 12 weeks, and the total number of sessions ranged from 6 to 60.
Participants included in the review
Schizophrenic patients were eligible. There was no a priori definition of schizophrenia. Patients in the review included schizophrenic patients with a first episode, chronic in- and out-patients, chronic paranoid, and undifferentiated schizophrenic in-patients.
Outcomes assessed in the review
Studies that assessed attention functioning using external measure of outcome were eligible. Studies that assessed other cognitive functions as outcomes were excluded. The included studies used the following measures to assess outcomes: Attention Stress Test, d2; repeated psychological measures (word recognition, crossing out numbers); sustained attention (KVT); Stroop Interference; Stroop word; Stroop colour; reaction time differences; labyrinth test; mental arithmetic (KLT); span of apprehension; Continuous Performance Test; Wechsler Memory Scale; Trail-making Test (A and B); Search-a-word; and letter cancellation.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.