Impaired use of sentence context in patients with schizophrenia: a review

Background

It has been suggested that several of the heterogeneous manifestations of schizophrenia could be dependent on a specific impairment in the representation and maintenance of context information. In the domain of language, a number of studies have shown disordered use of single-word contexts in patients with schizophrenia; however, natural language comprehension generally involves longer sequences of words, such as sentences. The aim of the present study was to review findings regarding the use of sentence context in schizophrenia.

Materials and methods

A MEDLINE search was performed to retrieve studies that have investigated the use of sentence context in patients with schizophrenia. The keywords “sentence”, “context” and “schizophrenia” were used; moreover, the references section of the retrieved papers was searched for similar studies.

Results

A total of 17 studies were traced. Patients with schizophrenia were invariably found impaired in their ability to benefit from sentence context. However, no single mechanism can unequivocally account for this deficit. There is evidence in favor of impairments both in the construction of a sentence context representation and in the use of the latter to guide lexical processing. Moreover, findings are inconclusive as to whether the reported disturbances reflect impairments in lexical or extralexical processes. These divergent findings can be explained if one assumes that the deficit is not unitary, and that various aspects of context processing are differentially affected in different patients; indeed, this view has received support by more recent studies.

Conclusions

The impaired use of sentence context in patients with schizophrenia appears to reflect disturbances in various levels of processing, which are possibly differentially affected in different patients.