Article

Auditory Working Memory Impairments in Individuals at Familial High Risk for Schizophrenia

Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA.
Neuropsychology (Impact Factor: 3.43). 05/2012; 26(3):288-303. DOI: 10.1037/a0027970
Source: PubMed

ABSTRACT The search for predictors of schizophrenia has accelerated with a growing focus on early intervention and prevention of psychotic illness. Studying nonpsychotic relatives of individuals with schizophrenia enables identification of markers of vulnerability for the illness independent of confounds associated with psychosis. The goal of these studies was to develop new auditory continuous performance tests (ACPTs) and evaluate their effects in individuals with schizophrenia and their relatives.
We carried out two studies of auditory vigilance with tasks involving working memory (WM) and interference control with increasing levels of cognitive load to discern the information-processing vulnerabilities in a sample of schizophrenia patients, and two samples of nonpsychotic relatives of individuals with schizophrenia and controls. Study 1 assessed adults (mean age = 41), and Study 2 assessed teenagers and young adults age 13-25 (M = 19).
Patients with schizophrenia were impaired on all five versions of the ACPTs, whereas relatives were impaired only on WM tasks, particularly the two interference tasks that maximize cognitive load. Across all groups, the interference tasks were more difficult to perform than the other tasks. Schizophrenia patients performed worse than relatives, who performed worse than controls. For patients, the effect sizes were large (Cohen's d = 1.5), whereas for relatives they were moderate (d = ~0.40-0.50). There was no age by group interaction in the relatives-control comparison except for participants <31 years of age.
Novel WM tasks that manipulate cognitive load and interference control index an important component of the vulnerability to schizophrenia.

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    • "divide attention and prevent counting, and presumably burden especially the cognitive processes of attention control. Following the original paradigm, we defined WM load as the number of letters between the cue and the target, while level of interference was defined as the number of distractors ( " Qs " and " As " ) embedded between the cue and the target (Seidman et al., 2012). Noticeably, the increase of load corresponds to the prolonged delay between the cue and the target, which has been previously shown to increase activity in left DLPFC (Barch et al., 1997), a load effect observed by the same research group in their other study using a parametric N-back task (Braver et al., 1997). "
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