Computer-assisted cognitive remediation therapy: cognition, self-esteem and quality of life in schizophrenia

BACKGROUND

Quality of life (QoL) is an important outcome in the treatment of schizophrenia. Cognitive deficits have an impact on functional outcomes. Cognitive remediation therapy is emerging as a psychological intervention that targets cognitive impairment, but the effect of computer-assisted cognitive remediation on neuropsychology and social functioning and wellbeing remains unclear. The aim of the current study is to investigate the neurocognitive outcomes of computer-assisted cognitive remediation (CACR) therapy in a sample of schizophrenia patients, and to measure the quality of life and self-esteem as secondary outcomes.

METHODS

Sixty-seven people with schizophrenia were randomly assigned to computer-assisted cognitive remediation or an active control condition. The main outcomes were neuropsychological measures and secondary outcomes (self-esteem and quality of life). Measurements were recorded at baseline and post-treatment.

RESULTS

The CACR therapy group improved in speed of processing, working memory and reasoning and problem-solving cognitive domains. QoL and self-esteem measures also showed significant improvements over time in this group.

CONCLUSIONS

Computer-assisted cognitive remediation therapy for people with schizophrenia achieved improvements in neuropsychological performance and in QoL and self-esteem measurements.

Changes in PAD patterns of group I muscle afferents after a peripheral nerve crush

In the anesthetized cat we have analyzed the changes in primary afferent depolarization (PAD) evoked in single muscle spindle and tendon organ afferents at different times after their axons were crushed in the periphery and allowed to regenerate. Medial gastrocnemius (MG) afferents were depolarized by stimulation of group I fibers in the posterior biceps and semitendinosus nerve (PBSt), as soon as 2 weeks after crushing their axons in the periphery, in some cases before they could be activated by physiological stimulation of muscle receptors. Two to twelve weeks after crushing the MG nerve, stimulation of the PBSt produced PAD in all MG fibers reconnected with presumed muscle spindles and tendon organs. The mean amplitude of the PAD elicited in afferent fibers reconnected with muscle spindles was increased relative to values obtained from Ia fibers in intact (control) preparations, but remained essentially the same in fibers reconnected with tendon organs. Quite unexpectedly, we found that, between 2 and 12 weeks after crushing the MG nerve, stimulation of the bulbar reticular formation (RF) produced PAD in most afferent fibers reconnected with muscle spindle afferents. The mean amplitude of the PAD elicited in these fibers was significantly increased relative to the PAD elicited in muscle spindle afferents from intact preparations (from 0.08 +/- 0.4 to 0.47 +/- 0.34 mV). A substantial recovery was observed between 6 months and 2.5 years after the peripheral nerve injury. Stimulation of the sural (SU) nerve produced practically no PAD in muscle spindles from intact preparations, and this remained so in those afferents reconnected with muscle spindles impaled 2-12 weeks after the nerve crush. The mean amplitude of the PAD produced in afferent fibers reconnected with tendon organs by stimulation of the PBSt nerve and of the bulbar RF remained essentially the same as the PAD elicited in intact afferents. However, SU nerve stimulation produced a larger PAD in afferents reconnected with tendon organs 2-12 weeks after the nerve crush (mean PAD changed from 0.05 +/- 0.04 to 0.32 +/- 0.17 mV). The results obtained indicate that the PAD patterns of the afferent fibers reconnected with muscle spindle and tendon organ afferents are changed after crushing their axons in the periphery: stimulation of the bulbar RF appears to produce larger PAD in fibers reconnected with muscle spindles, and stimulation of cutaneous afferents produces larger PAD in fibers reconnected with tendon organs. It is suggested that these alterations in the patterns of PAD of muscle afferents result from central changes in the balance of excitatory and inhibitory influences acting on the segmental pathways mediating the PAD. Although the functional role of these changes has not been established, they may reflect compensatory changes aimed to adjust information arising from damaged afferents.

Segmental and supraspinal control of synaptic effectiveness of functionally identified muscle afferents in the cat

The present investigation documents the patterns of primary afferent depolarization (PAD) of single, functionally identified muscle afferents from the medial gastrocnemius nerve in the intact, anesthetized cat. Classification of the impaled muscle afferents as from muscle spindles or from tendon organs was made according to several criteria, which comprised measurement of conduction velocity and electrical threshold of the peripheral axons, and the maximal frequency followed by the afferent fibers during vibration, as well as the changes in discharge frequency during longitudinal stretch, the projection of the afferent fiber to the motor pool, and, in unparalyzed preparations, the changes in afferent activity during a muscle twitch. In confirmation of a previous study, we found that most muscle spindle afferents (46.1-66.6%, depending on the combination of criteria utilized for receptor classification) had a type A PAD pattern. That is, they were depolarized by stimulation of group I fibers of the posterior biceps and semitendinosus (PBSt) nerve, but not by stimulation of cutaneous nerves (sural and superficial peroneus) or the bulbar reticular formation (RF), which in many cases inhibited the PBSt-induced PAD. In addition, we found a significant fraction of muscle spindle primaries that were depolarized by stimulation of group I PBSt fibers and also by stimulation of the bulbar RF. Stimulation of cutaneous nerves produced PAD in 9.1-31.2% of these fibers (type B PAD pattern) and no PAD in 8.2-15.4% (type C PAD pattern). In contrast to muscle spindle afferents, only the 7.7-15.4% of fibers from tendon organs had a type A PAD pattern, 23-46.1% had a type B and 50-61.5% a type C PAD pattern. These observations suggest that the neuronal circuitry involved in the control of the synaptic effectiveness of muscle spindles and tendon organs is subjected to excitatory as well as to inhibitory influences from cutaneous and reticulospinal fibers. As shown in the accompanying paper, the balance between excitation and inhibition is not fixed, but can be changed by crushing the afferent axons in the peripheral nerve and allowing subsequent reconnection of these afferent fibers with muscle receptors.