Differential improvement of negative-symptom subfactors after cognitive remediation in low-functioning individuals with schizophrenia.

BACKGROUND: Negative symptoms and cognitive deficits have a substantial predictive value for functional deficits and recovery in schizophrenia. However, the relationship between negative symptoms and cognitive abnormalities is unclear possibly due to the heterogeneity of negative symptoms. This study used the model of expressive and experiential negative symptoms subfactors to decrease this heterogeneity. It examined these subfactors and cognition before and after treatment with computerized cognitive remediation training (CRT) in chronically-hospitalized individuals with psychosis and predominant negative symptoms. METHODS: Seventy-eight adult participants with a DSM-IV-TR diagnosis of schizophrenia or schizoaffective disorder were enrolled in a 12-week CRT program. Assessments of demographic and illness variables, baseline and endpoint assessments of psychopathology (Positive and Negative Syndrome Scale) and cognition (MATRICS Consensus Cognitive Battery - MCCB) were conducted. RESULTS: The baseline expressive negative subfactor was associated with Processing Speed (r = -0.352, p ≤ 0.001) and Reasoning/Problem Solving (r = -0.338, p ≤ 0.001). Following CRT, there was a significant decrease in the experiential negative subfactor (p < 0.01) but not of the expressive negative subfactor. Change in MCCB domains after CRT accounted for 51.1% and 50.2% of the variance of change in expressive and experiential negative subfactor scores, respectively. For both subfactors, Visual Learning was a significant predictor of change (p < 0.05). CONCLUSION: Our findings suggest that CRT has benefits for negative symptoms in very low-functioning patients and that this change may be in part mediated by change in cognitive functions after CRT.

Transcranial direct-current stimulation in ultra-treatment-resistant schizophrenia.

BACKGROUND: Transcranial direct-current stimulation (tDCS), a non-invasive neurostimulation treatment, has been reported in a number of sham-controlled studies to show significant improvements in treatment-resistant auditory hallucinations in schizophrenia patients, primarily in ambulatory and higher-functioning patients, but little is known of the effects of tDCS on hospitalized, low-functioning inpatients. OBJECTIVE/HYPOTHESIS: The purpose of this study was to examine the efficacy and safety of tDCS for auditory hallucinations in hospitalized ultra-treatment-resistant schizophrenia (TRS) and to evaluate the effects of tDCS on cognitive functions. We hypothesized that treatment non-response reported in previous tDCS studies may have been due to the insufficient duration of direct-current stimulation. METHODS: Inpatient participants with DSM-V schizophrenia, long-standing treatment-resistance, and auditory verbal hallucinations (AVH) participated in this 4-week sham-controlled, randomized trial. Assessments included the Positive and Negative Syndrome Scale (PANSS) and MATRICS Consensus Cognitive Battery (MCCB) at baseline and endpoint (at the end of Week 4), and the Auditory Hallucinations Rating Scale (AHRS) administered at baseline, endpoint, and weekly throughout the study. Participants were randomized to receive active vs. sham tDCS treatments twice daily for 4 weeks. RESULTS: Twenty-eight participants were enrolled (tDCS, n = 15; control, n = 13) and 21 participants completed all 4 weeks of the trial. Results showed a significant reduction for the auditory hallucination total score (p ≤ 0.05). We found a 21.9% decrease in AHRS Total Score for the tDCS group and a 12.6% decrease in AHRS Total Score for the control group. Significant reductions in frequency, number of voices over time, length of auditory hallucinations, and overall psychopathology were also observed for the tDCS group. When assessing cognitive functioning, only Working Memory showed improvement for the tDCS group. CONCLUSION: Although there was only a small improvement noted in auditory hallucination scores for the tDCS group, this improvement was meaningful when compared to no standard treatment of the control group. While this makes the interpretation of clinical significance debatable, it does confirm that tDCS combined with pharmacological intervention can provide clinical gains over pharmacological intervention alone. Therefore, tDCS treatment appears to be effective not only for ambulatory, higher-functioning patients, but also for patients with ultra-treatment-resistant schizophrenia.

Does social cognition training augment response to computer-assisted cognitive remediation for schizophrenia?

OBJECTIVES: Cognitive remediation therapy (CRT) has shown significant improvement in cognition in schizophrenia. However, effect sizes of CRT have been reported to be modest raising the issue how to augment the effects of CRT on neurocognition and social cognition. Our aim was to examine whether the addition of computerized social cognition training would enhance the effects on neurocognition and social cognition as compared to CRT alone. METHODS: This is a 12-week, parallel group trial of 131 in- and out-patients with schizophrenia randomized to CRT (COGPACK or Brain Fitness) with computerized social cognition training (MRIGE), or CRT alone for 36 sessions. Participants were assessed at baseline and after 12 weeks of treatment. Assessments included neurocognition, social cognition, psychopathology, and functioning. RESULTS: The combined intervention, CRT + MRIGE, showed greater improvements in the MCCB indices of Visual Learning, Working Memory, Reasoning and Problem-Solving, and the neurocognitive composite score compared to CRT alone (Bonferroni adjusted p = 0.004, p = 0.005, p = 0.01, respectively), as did social cognition measures (Bonferroni adjusted p = 0.006, p = 0.005, respectively). CONCLUSIONS: Supplementing CRT with computerized social cognition training produced greater benefits in neurocognition, including visual learning, memory, executive functions, and social cognition relative to cognitive training alone. These findings favoring the combined training may be contributed to both the greater overall amount of cognitive practice, as well as the specific cognitive functions engaged by the social cognition training.

Acquisition, representation, and transfer of models of visuo-motor error.

We examined how human subjects acquire and represent models of visuo-motor error and how they transfer information about visuo-motor error from one task to a closely related one. The experiment consisted of three phases. In the training phase, subjects threw beanbags underhand towards targets displayed on a wall-mounted touch screen. The distribution of their endpoints was a vertically elongated bivariate Gaussian. In the subsequent choice phase, subjects repeatedly chose which of two targets varying in shape and size they would prefer to attempt to hit. Their choices allowed us to investigate their internal models of visuo-motor error distribution, including the coordinate system in which they represented visuo-motor error. In the transfer phase, subjects repeated the choice phase from a different vantage point, the same distance from the screen but with the throwing direction shifted 45°. From the new vantage point, visuo-motor error was effectively expanded horizontally by √2. We found that subjects incorrectly assumed an isotropic distribution in the choice phase but that the anisotropy they assumed in the transfer phase agreed with an objectively correct transfer. We also found that the coordinate system used in coding two-dimensional visuo-motor error in the choice phase was effectively one-dimensional.