Elsevier

Schizophrenia Research

Volume 59, Issues 2–3, 1 February 2003, Pages 225-232
Schizophrenia Research

Computer-assisted cognitive rehabilitation reduces negative symptoms in the severely mentally ill

https://doi.org/10.1016/S0920-9964(01)00402-9Get rights and content

Abstract

Thirty-four-day treatment program clients diagnosed with schizophrenia or schizoaffective disorder were randomly assigned to a computer-assisted cognitive rehabilitation (CACR) group or a wait-list Control group. CACR clients received 16 CACR sessions over an 8-week period. Measures of cognitive functioning, negative symptoms and self-esteem were administered at the beginning and end of this period. CACR clients showed greater improvement in cognitive functioning (verbal memory and attention) and negative symptoms. Symptom reduction was not mediated by raised self-esteem. CACR's effects may go beyond cognitive remediation to include some of the most disabling and refractory clinical features of schizophrenia.

Introduction

Cognitive impairment is a key feature of schizophrenia and related disorders. In a recent review, Rund (1998) found substantial evidence for a generalized cognitive decline among people with schizophrenia, in addition to specific deficits in memory and attention. These impairments are consequential, often enduring over long periods and impeding recovery. Even patients whose symptoms have remitted “continue to experience the real-world impact of their cognitive dysfunctions on sociovocational functioning, quality of life, family burden, and ability to profit from therapy” (Spring and Ravdin, 1992, p.18). Supporting this claim, Silverstein et al. (1998a) found that cognitive deficits predicted poorer outcomes in social skills training groups, daily functioning on an inpatient ward, and discharge from hospital.

These cognitive deficits may be linked to negative symptoms. This link was postulated by Neuchterlein et al. (1986), who argued that reduced cognitive resources might contribute to symptoms such as apathy and affective flattening by restricting the depth and breadth of cognitive processing. Goldberg and Cook (1996) explained how specific symptoms might arise in this way (e.g., poverty of speech due to deficient executive functioning). Rund (1998) reviewed evidence that patients with the most prominent negative symptoms are the most cognitively impaired, and Nieuwenstein et al.'s (2001) recent meta-analysis demonstrates a robust association of impaired executive functioning and sustained attention with negative but not positive symptoms. The debilitating consequences of cognitive deficits for people with schizophrenia appear to be at least partly due to their association with these traditionally treatment-refractory symptoms.

Given the crucial role of cognitive impairment in schizophrenia, efforts have been made to develop suitable forms of cognitive (or “neurocognitive”) rehabilitation (see Silverstein, 2000, for a review). In their support, Corrigan and Storzbach (1993) argued that improvement in basic cognitive functions (e.g., attention and vigilance) should also promote more complex functions. Thus, “remediation of cognitive deficits would necessarily precede macrolevel rehabilitation of daily life and sociovocational skills” (Spring and Ravdin, 1992, p. 17). Several studies attempting to improve cognitive functioning have yielded encouraging results (e.g., Ahmed and Goldman, 1994, Bellack et al., 1990, Brenner et al., 1992, Cassidy et al., 1996, Silverstein et al., 1998b). These studies shows that even relatively brief interventions can produce significant improvements in basic cognitive functions such as attention, concentration, and working memory. Such improvements are evident even in comparison to control groups receiving alternative treatments, such as supportive or occupational therapies Spaulding et al., 1999b, Wykes et al., 1999.

Evidence that cognitive rehabilitation produces significant effects on basic cognitive functions is strong. There is much less evidence that it has broader clinical effects, such as improved social and occupational functioning or reduced symptoms. Wykes et al. (1999), for instance, found that improved cognitive flexibility resulting from an intensive “neurocognitive remediation” program predicted better post-treatment social functioning, but that it had no effect on symptom measures. Similarly, Spaulding et al. (1999b) found that cognitive rehabilitation had significant effects on severely disabled patients' social competence and symptom and medication management skills, but no symptomatic effects besides an equivocal reduction in disorganized symptoms. Thus, the broader clinical efficacy of cognitive rehabilitation has yet to be fully established.

Increasingly cognitive rehabilitation has involved the use of computers. Computer-assisted cognitive rehabilitation (CACR) has several advantages, providing structured, flexible and standardized training tasks with clear, accurate and immediate feedback. In addition, CACR is economical, saving professional time, and may appeal to patients who see working with a human therapist as threatening and prefer the “nonjudgmental” computer. As Bloom (1992) states, “even [patients] who are quite disturbed interact very successfully with computers, including many...who are unable to interact with mental health personnel” (p. 169).

Several studies have examined the effects and varying implementations of CACR. Bradt et al. (1993), Brieff (1994) and Burda et al. (1991) reported little quantitative information and no statistical evidence for efficacy, and had no control group. Nevertheless, all reported that CACR was enthusiastically received by patients. Bradt et al. (1993) and Burda et al. (1991) observed informally that CACR raised patients' self-esteem. Among the more controlled investigations, Burda et al. (1994) found that patients with schizophrenia or schizoaffective disorder who completed a comprehensive CACR program improved significantly on measures of memory and attention, whereas control subjects did not. Benedict et al.'s (1994) controlled trial of a more circumscribed attentional rehabilitation program yielded some attentional improvement that did not generalize. Medalia et al.'s (1998) similar program improved inpatients' performance on measures of vigilance and reduced general psychiatric disturbance. Hogarty and Flesher's (1999) preliminary report on a partly computerized and year-long “cognitive enhancement therapy” indicates significant improvement on attention, memory and problem-solving and clinician-rated social cognition and disability, and nonsignificant but “encouraging” improvements in self-esteem. Bell et al.'s (2000) similarly intensive and partly computerized program yielded several large improvements in working memory and executive functioning even relative to a cognitively stimulating work therapy program.

This research indicates that CACR is a promising treatment modality. However, as with other forms of cognitive rehabilitation, evidence is lacking that it goes beyond remediating cognitive functions to influence additional clinically significant outcomes such as symptoms. Given that a major rationale for cognitive rehabilitation is that it should improve broader psychological functioning beyond the basic cognitive processes that it targets, this is an important limitation. The likehood that cognitive deficits at least partially account for negative symptomatology, and the chronicity associated with it, suggests that improvement in negative symptoms might be an appropriate goal for CACR.

In view of the existing limitations in the research literature, an experimental study was conducted on the effectiveness of CACR in reducing negative symptoms and improving basic cognitive processes. The study also examined whether any effect of CACR on negative symptoms might be mediated by the raised self-esteem noted by other researchers. If this were the case, some of CACR's clinical benefits might derive from improved motivation or mood rather than from direct effects on cognitive functioning or reward mechanisms. We hypothesized that CACR would significantly improve cognitive functioning and reduce negative symptoms, and that improved self-esteem would mediate the latter effect.

Section snippets

Subjects

Subjects were 34 adult clients attending a day treatment program offering medication management, psychiatric evaluation, case management services, and therapeutic groups (e.g., psychoeducation, social skills, prevocational training). Primary diagnoses made by treating psychiatrists using a structured clinical interview were schizoaffective disorder (n=18) or schizophrenia (n=16) judged to have been present for ≥6 months. Clients over the age of 60 were excluded, as were those judged to be

Results

Analysis of pretest scores on the 21 dependent measures revealed only one significant difference between the groups, with the CACR group scoring higher than the Controls on the MMSE (t(32)=2.39, p<0.05). Given the number of comparisons, this is best considered a chance finding, suggesting that the groups were generally equivalent in degree of impairment at baseline. The CACR group showed weak, nonsignificant trends toward being more cognitively impaired but higher in negative symptoms and lower

Discussion

The findings were generally supportive of the study hypotheses. CACR yielded significant improvement on several measures of cognitive functioning, replicating earlier CACR findings (e.g., Bell et al., 2001, Burda et al., 1994). These improvements are unlikely to be due to a generalized practice effect, as none of the CACR tasks closely resembled the cognitive assessment tasks and none presented material verbally. Improvements were clearest for measures of verbal/conceptual learning and memory

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