When Top-Down Meets Bottom-Up: Auditory Training Enhances Verbal Memory in Schizophrenia

Abstract

A critical research priority for our field is to develop treatments that enhance cognitive functioning in schizophrenia and thereby attenuate the functional losses associated with the illness. In this article, we describe such a treatment method that is grounded in emerging research on the widespread sensory processing impairments of schizophrenia, as described elsewhere in this special issue. We first present the rationale for this treatment approach, which consists of cognitive training exercises that make use of principles derived from the past 2 decades of basic science research in learning-induced neuroplasticity; these exercises explicitly target not only the higher order or "top-down" processes of cognition but also the content building blocks of accurate and efficient sensory representations to simultaneously achieve "bottom-up" remediation. We then summarize our experience to date and briefly review our behavioral and serum biomarker findings from a randomized controlled trial of this method in outpatients with long-term symptoms of schizophrenia. Finally, we present promising early psychophysiological evidence that supports the hypothesis that this cognitive training method induces changes in aspects of impaired bottom-up sensory processing in schizophrenia. We conclude with the observation that neuroplasticity-based cognitive training brings patients closer to physiological patterns seen in healthy participants, suggesting that it changes the brain in an adaptive manner in schizophrenia.

Cognitive Remediation for Schizophrenia: A Review of Recent Findings

“…The other study concluded there were no gains in neurocognition and no changes in electroencephalogram (EEG) measures following 40 hours of BrainFitness training [36]. Two other studies [37,38] that were published before our publication period showed improved verbal memory and auditory neural responses (M100) after intensive auditory training. The MEG findings contradict Rass et al's study [36], but are in line with the original neuroplasticity-based studies from Fisher and colleagues [34,39], which reported significant improvements in verbal learning and memory and global cognition, and maintenance of treatment gains at 6- month follow-up.…”

Cognitive Remediation for Schizophrenia

“…More importantly, they demonstrated that these basic improvements were associated with improvements in higher order functions, including linguistic processing, verbal cognition, and general cognition and that these changes were durable six months after training had concluded. 77) Similarly, a social cognition training regimen that included practice in the basic skill of emotion perception was demonstrated to improve not only social cognition, but also social functioning in patients with schizophrenia, suggesting that the benefits generalize from test performance to actual functioning. 80) Cognitive therapies, therefore, must both recognize and address the perceptual processing impairments that are present in schizophrenia if maximal improvements in higher order cognitive func-tions are to be achieved.…”

“…Because deficits in simple perception necessitate an increased attentional load and recruitment of top-down operations to achieve basic processing, 77) fewer top-down resources are available for higher-level cognitive operations. 78) Given this connection, there is increasing emphasis on the idea that training targeting basic sensory processes and simple cognitive functions will ultimately benefit higher-level cognitive operations.…”

“…79) Similar studies are beginning to emerge in schizophrenia research. For example, Adcock et al 77) have shown that an auditory training regimen can induce improvements in impaired sensory processing, such as the ability to distinguish two similar syllables. More importantly, they demonstrated that these basic improvements were associated with improvements in higher order functions, including linguistic processing, verbal cognition, and general cognition and that these changes were durable six months after training had concluded.…”

Deep Brain Stimulation in Schizophrenia

“…However, it appears questionable if the modulation of a particular symptom embedded in a system of various disordered components leads to a recovery from the full range of deficits. Sensory processing and higher order cognitive performance display mutual dependence: perception contributes significantly to proper cognition (bottom-up) and cognition, in turn, modulates perception (top-down) (Javitt, 2009;Adcock et al, 2009). Thus, framing a valid hypothesis regarding schizophrenia by assuming a close relationship between phenomenology and neurophysiology appears critical.…”