Neurocognitive enhancement therapy with work therapy in schizophrenia: 6-month follow-up of neuropsychological performance.

INTRODUCTION Recent reviews of the efficacy of cognitive rehabilitation as a method to improve cognitive functioning in schizophrenia have generally been positive [1-6], although one review was equivocal [7]. The remediation of cognitive deficits is potentially clinically significant because cognitive abilities have been shown to be related to self-esteem, work success, skills acquisition, independent living, and quality of life [8-9]. A key question for judging the clinical value of cognitive remediation is whether gains made during training endure beyond the training period. If such gains do not endure past the training phase, it is unlikely that they would generalize to other areas or that they would significantly affect the impact of other psychosocial interventions that rely on adequate processing and retention of presented material. This study investigates the durability of performance effects on standard neuropsychological tests 6 months after completion of neurocognitive enhancement therapy (NET) [10], a 26-week cognitive training program. Only a handful of reports have been published on the durability of cognitive training effects. Many of these have focused on the durability of gains achieved during training on a single task (e.g., Wisconsin Card Sorting Test [WCST] or Span of Apprehension) and, in general, indicate that improvements are sustained, although follow-up periods have been relatively brief, 6 weeks at most [11-15]. In a longer follow-up study of training effects for two computerized memory training tasks, we reported that gains made on these tasks were sustained at a 6-month follow-up [16]. In another study, Wexler et al. noted that trained-task gains were sustained at a 6-month follow-up for half the patients (three of six) who returned for follow-up testing after a 10-week remediation program of visual reading, dot localization, and manual dexterity tasks [17]. Combined, these studies support the durability of task-specific training effects. Far less is known about whether cognitive remediation gains generalize to untrained tasks and whether those improvements, in turn, are sustained. This question is important, because the overall goal of cognitive remediation programs is to improve general cognitive function, not just performance on the trained tasks. Medalia et al. reported that a 5-week problem-solving remediation program was associated with sustained improvements on problem-solving tasks at a 4-week follow-up [18]. In another arm of the study [19] during which participants completed a 5-week memory remediation course using computer-based educational software, while trained tasks improved, these improvements did not generalize to untrained tasks, as assessed at a 4-week follow-up. In contrast, Corrigan et al. reported that a single session of memory and vigilance training with a social cue recognition test was associated with sustained improvements on an untrained cue recognition test administered 2 days later [20]. Several other studies are also encouraging, suggesting that improvements on untrained tasks may persist as long as 6 months following training. Wykes et al., for example, reported that gains on a verbal memory task made following a 40-session course of cognitive remediation training were maintained at a 6-month follow-up [21]. Similarly, our research team has reported that a 6-month cognitive remediation program was associated with improvements on an untrained working memory task and that these improvements were sustained at a 6-month follow-up [22]. In 2001, we demonstrated that an integrated work therapy (WT)/cognitive rehabilitation program (NET) resulted in significant cognitive improvements for people with schizophrenia or schizoaffective disorder [10]. In a randomized controlled study, participants were enrolled in either NET + WT or WT only. At study entry, both groups performed poorly on neuropsychological testing. Participants receiving NET + WT showed greater improvements than those receiving WT on pre- and posttestings of executive function and working memory. …