Impaired performance in a working memory binding task in patients with schizophrenia.

This study investigated feature binding in a working memory task in patients with schizophrenia and in normal controls. Twenty-five patients and 25 controls participated. On each trial, three drawings of familiar objects were presented sequentially, each in a different cell of a 3 x 3 grid. In different blocks of trials, participants remembered either individual features (object and location conditions) or an object and its location (combination condition). The results showed that patients were slower and less accurate than controls under all conditions. Accuracy of both groups was reduced in the combination condition relative to the single-feature conditions, but patients showed disproportionately poorer performance in the combination condition than in the object and location conditions. Thus, patients with schizophrenia exhibit deficits in working memory, particularly when the task requires binding objects to their locations. This finding demonstrates that processes that establish coherent and temporary episodic representations in working memory are impaired in schizophrenia.

Further evidence of the multi-dimensionality of hallucinatory predisposition: factor structure of a modified version of the Launay-Slade Hallucinations Scale in a normal sample.

Recent years has seen an increasing interest in the hallucinatory experience, including investigations of its phenomenological prevalence and character both in pathological and normal (predisposed) populations. We investigated the multi-dimensionality of hallucinatory experiences in 265 subjects from the normal population, who completed a modified version of the Launay-Slade Hallucinations Scale. Principal components analysis was performed on the data. Four factors were obtained loading on items reflecting (1) sleep-related hallucinatory experiences (2) vivid daydreams (3) intrusive thoughts or realness of thought and (4) auditory hallucinations. The results offer further evidence of the multi-dimensionality of hallucinatory disposition in the normal population. Directions for future research in hallucinatory predisposition are discussed.