Linguistic Analysis of the Speech Output of Schizophrenic, Bipolar, and Depressive Patients

Abstract

Using speech samples of 100 patients suffering from schizophrenia, bipolar illness and major depression, we addressed the question of the extent to which the linguistic abnormalities in the speech of these patients represent diagnosis-specific characteristics or constitute independent, syndrome-like dimensions of the illnesses. All speech samples were transcribed by a professional linguist who was blind to both identity and diagnosis of the patients. The majority of the deviant linguistic variables was found to be common to all three diagnostic groups under comparison, while only a few linguistic variables exhibited statistically significant between-group differences. On the other hand, when the respective variables were analysed as a multivariate entity, the variety of subtle between-group differences allowed us to discriminate between the diagnostic groups at an overall performance of 72.7% correctly classified patients. There was an almost complete lack of association between linguistic abnormalities and psychopathology syndromes. In particular, we found no correlation between the syndrome ‘formal thought disorder’ and the large variety of linguistic variables used in this investigation. In consequence, we conjecture that linguistically deviant speech characteristics represent an independent syndrome complex manifested at varying intensities across mental illnesses, and that this syndrome complex deserves greater attention, not only with respect to the principal understanding of the underlying disturbances, but also as a potential target of therapeutical intervention.

Interpretation of Ambiguous Idiomatic Statements in Schizophrenic and Depressive Patients. Evidence for Common and Differential Cognitive Patterns

“…Concrete responses reached a level of 15% in the depressive group and 11% in the schizophrenic group. This result confi rms (a) the presence of a common pattern of language disorders in schizophrenia patients and depressive patients [48] , in particular in tasks that test metaphor comprehension [33][34][35] , and (b) shows that this pattern relates to the presence of concrete elements, thus eliminating an analysis of the global meaning [32] of the semantic material. It is important to point out the crucial difference between concrete responses as defi ned in the present study and concretistic thinking and behavior typically described in schizophrenic patients in phenomenological descriptions of the disorder [49] .…”

Affective State and Voice: Cross-Cultural Assessment of Speaking Behavior and Voice Sound Characteristics - a Normative Multicenter Study of 577 + 36 Healthy Subjects

“…During recovery, however, the patients' speaking behavior and voice sound characteristics return to ‘normal' values. On the group level this can readily be demonstrated under various experimental settings [e.g., [1,2,3,4,5,6,7]]. Yet things get much more complex if focus is laid on longitudinal changes in the individual patient over time (single-case analysis), for example, when clinicians monitor speaking behavior and voice sound characteristics among affectively disturbed patients for diagnostic purposes and as indicators of clinical change (e.g., among patients recovering from depression, or among patients at risk of relapse after having recovered from depression).…”

Linguistic production and syntactic comprehension in schizophrenia and bipolar disorder

“…If a general consensus can be found among scholars on the presence of linguistic difficulties in persons with schizophrenia (1)(2)(3), data regarding the potential incidence of linguistic deficits in individuals with bipolar disorder are still controversial (4)(5)(6)(7)(8)(9)(10)(11). However, the incidence and characteristics of linguistic difficulties among different pathologies is still an open debate.…”