Cognitive impairments and disordered speech in schizophrenia: thought disorder, disorganization, and communication failure perspectives

This article posits that basic cognitive impairments in schizophrenia are more highly related to speech disorder measured as communication failures than speech disorder measured as thought disorder or disorganization. The author tested 47 schizophrenia patients and 36 control participants for sustained attention, sequencing, and conceptual sequencing ability. Their speech was also rated for communication failures, thought disorder, and conceptual disorganization. Attention and sequencing impairments, examined hierarchically, explained a substantial 38% of the variance in the communication measure of speech disorder but little of the variance in formal thought disorder or conceptual disorganization. The author concludes that (a) impairments in attention and sequencing abilities contribute substantially to schizophrenic communication failures, and (b) it is important to consider lower level cognitive "3rd variables" when examining higher level cognitive associates of speech disorder.     

Stability of formal thought disorder and referential communication disturbances in schizophrenia

This study examined the degree to which different types of communication disturbances in the speech of 48 schizophrenia patients and 28 controls were variable and state related versus stable and traitlike. Clinically rated formal thought disorder and 5 types of referential disturbance showed substantial stability within participants over time. The sixth type of referential disturbance, the vague reference, was not stable over time. Formal thought disorder was associated with the severity of core psychotic symptoms in patients. whereas referential disturbances showed little or no association with positive or negative symptom severity. Furthermore, changes in psychotic symptoms over time were accompanied by corresponding changes in formal thought disorder but not referential disturbances. These results support the idea that some types of referential disturbances are traitlike and may be reflective of vulnerability as well as manifest illness.     

Verbal communication impairments and cognitive control components in people with schizophrenia

Schizophrenia involves multiple communication impairments, including (a) disorganized speech, or formal thought disorder (FTD); and (b) decreased speech output, or poverty of speech. Both FTD and poverty of speech have been hypothesized to be associated with deficits in executive functioning or cognitive control. The current study examined whether FTD and poverty of speech were differentially associated with two distinct aspects of cognitive control, working memory and controlled retrieval. Compared with control participants (n = 30), people with schizophrenia (n = 47) exhibited poorer performance on both working memory and controlled retrieval tasks. However, only FTD (and not poverty of speech) was associated with poor working memory. In contrast, only poverty of speech (and not FTD) had a significant zero-order association with poor controlled retrieval. At the same time, working memory and controlled retrieval interacted to predict FTD, with the highest amount of FTD associated with both poor working memory and poor controlled retrieval. In contrast, psychometric control tasks were not associated with FTD or poverty of speech. This research suggests that FTD and poverty of speech are differentially associated with deficits in distinct aspects of cognitive control.     

Trauma and posttraumatic stress disorder in people with schizophrenia

This study evaluated the hypothesis that trauma and posttraumatic stress disorder (PTSD) severity would be positively associated with schizophrenia symptoms. Forty-seven clients with schizophrenia were assessed for schizophrenia severity and for lifetime trauma history and PTSD symptoms in 2 independent symptom interviews; 35 (74%) participants reported at least 1 event in which there was threat of harm or life threat and subjective distress, and 6 (13%) had current PTSD. Trauma across the life span was associated with greater severity of PTSD. Within the total sample, PTSD symptoms were associated with greater emotional distress, but not with schizophrenia-specific symptoms. Distress among clients with schizophrenia and PTSD suggests the need for routine assessment of PTSD and development of PTSD interventions in this population.     

Interrater reliability and coding guide for nonpsychotic formal thought disorder

Reliable and valid assessment of abnormal speech patterns may enable earlier recognition of nonpsychotic disorders through characteristic speech patterns. This study sought to establish interrater reliability using a standardized guide for scoring. A scoring guide defining 27 elements (e.g., inappropriate self-reference, simple loss of goal, circumstantiality) of disordered thought was developed. The seminal work of Andreasen's and Holzman's groups provided 12 elements, and 15 new elements were suggested by clinical literature. Audiotaped interviews with 12 psychiatric inpatients, adults of both sexes and various ages hospitalized for acute management of nonpsychotic psychiatric disorders, provided speech samples for observation of disordered thought by two independent raters. Using the guide's definitions and accompanying examples of elements of disordered thought, reliability in scoring was high (kappa of .85 for agreement on the presence of any abnormal speech element and kappa values from .66 to 1.00 for agreement on the presence of individual elements).     

The relationship between formal thought disorder and executive functioning component processes

In 2 studies, associations between formal thought disorder (FTD) and 2 components of executive functioning, processing of context and interference resolution, were investigated. One study, involving people with schizophrenia, examined associations between performance on processing of context (N-back) and interference resolution (interference in Steinberg probe recognition) tasks and FTD. The second study, involving nonpsychiatric participants, was an analogue study that examined the effects of simulated processing of context (performance of 1-back with distraction) and interference resolution (telling new stories about previously seen pictures) deficits on FTD in a speech production task. In both studies, processing of context deficits predicted FTD. Moreover, in both studies, the effect of processing of context deficits on FTD was especially pronounced when combined with interference resolution deficits.     

Cognitive discernible factors between schizophrenia and schizoaffective disorder

BackgroundSchizophrenia (SZ) and schizoaffective disorders (SA) are associated with cognitive deficits. Generally, a schizoaffective diagnosis is associated with better prognosis on the level of social integration. It is also well established that cognition is an important factor for good social outcome in schizophrenia. We hypothesized that, although patients suffering from SA share symptoms with SZ, they can be differentiated on the basis of neurocognitive function and that SA perform better in several domains.MethodPerformances of two groups SA (N = 13) and SZ (N = 44) were compared on several visual-motor tasks using CANTAB [Motor Screening (MOT), Reaction Time (RTI), Paired Associates Learning Task (PAL), and Stockings of Cambridge items (SOC)]. The two groups were matched for symptom severity. ANOVA with repeated measures was employed to determine whether any difference in cognitive scores during a 2-year period was significantly related to the diagnostic status.ResultsA significant and durable difference was observed between SZ and SA on motor screening and explicit memory tests where SA performed better.ConclusionNeurocognitive tests may be relevant for distinguishing schizoaffective from schizophrenia, chiefly via tests tapping into visuo-spatial and visuo-motor coordination abilities (e.g., paired associated learning and motor screening).     

The effects of haloperidol on thought disorder and IQ in schizophrenia

The impact of haloperidol treatment on the Wechsler Adult Intelligence Scale (WAIS) and the Thought Disorder Index was investigated in a group of 19 patients with schizophrenia tested both before and after 26 days of treatment with haloperidol. Thought disorder scores declined significantly over the course of treatment and fewer patients demonstrated severe forms of thought disorder at the end of the trial. WAIS performance improved significantly but the magnitude of change was consistent with the literature on expected practice effects. Thought disorder scores were negatively correlated with IQ at baseline, but not at Day 26. The results suggest a partial dissociation of thought disorder and other cognitive functions in schizophrenia.     

Cognitive discernible factors between schizophrenia and schizoaffective disorder

BACKGROUND: Schizophrenia (SZ) and schizoaffective disorders (SA) are associated with cognitive deficits. Generally, a schizoaffective diagnosis is associated with better prognosis on the level of social integration. It is also well established that cognition is an important factor for good social outcome in schizophrenia. We hypothesized that, although patients suffering from SA share symptoms with SZ, they can be differentiated on the basis of neurocognitive function and that SA perform better in several domains. METHOD: Performances of two groups SA (N = 13) and SZ (N = 44) were compared on several visual-motor tasks using CANTAB [Motor Screening (MOT), Reaction Time (RTI), Paired Associates Learning Task (PAL), and Stockings of Cambridge items (SOC)]. The two groups were matched for symptom severity. ANOVA with repeated measures was employed to determine whether any difference in cognitive scores during a 2-year period was significantly related to the diagnostic status. RESULTS: A significant and durable difference was observed between SZ and SA on motor screening and explicit memory tests where SA performed better. CONCLUSION: Neurocognitive tests may be relevant for distinguishing schizoaffective from schizophrenia, chiefly via tests tapping into visuo-spatial and visuo-motor coordination abilities (e.g., paired associated learning and motor screening).     

Cognitive processing of multidimensional stimuli in schizophrenia: formal modeling of judgment speed and content

This article presents a formal, mathematical account of relations between response times on simple cognitive tasks and content of complex judgments involving multiple stimulus dimensions for people with schizophrenia. Changes in multidimensional judgments were viewed as the result of interference from increased stages of encoding with respect to the individual dimensions. Information on dimensional properties encoded earlier in a judgment trial was considered to be more susceptible to loss over the rest of the trial, because of a larger number of encoding stages applied to the remaining dimensional properties. Model predictions were tested with samples of paranoid and nonparanoid schizophrenic participants and controls. Unidimensional encoding speed was assessed by reaction times in an explicit similarity ratings task, and multidimensional judgment content was assessed by the relative importance of different stimulus dimensions to participants' ratings in an implicit similarity ratings task. Results support validity of the model.     

Capitalizing on formal thought in counseling adolescents on conflicts with parents

Parent-adolescent conflicts are frequently sufficiently severe to require third-party intervention. Because the adolescent is more likely to be in a setting where counsel is more easily available, the helping person can make use of insight and emotional maturity that is concomitant with the adolescent's acquisition of formal thought.     

Working memory impairments in schizophrenia: a meta-analysis

Working memory (WM) deficit is a cardinal cognitive symptom of schizophrenia, but the differences among the tasks and measures used to assess WM make it difficult to compare across studies. The authors conducted a meta-analytic review to address 3 major questions: (a) Do patients with schizophrenia show WM deficits across diverse methodology; (b) Is WM deficit supramodal; and (c) Does the WM deficit worsen with longer delays? The results indicate that significant WM deficit was present in schizophrenia patients in all modalities examined. Increasing delay beyond 1 s did not influence the performance difference between schizophrenia patients and healthy control participants in WM. These results suggest that WM deficit in schizophrenia is modality independent and that encoding and/or early part of maintenance may be problematic.     

EEG mu rhythm and imitation impairments in individuals with autism spectrum disorder

Imitation ability has consistently been shown to be impaired in individuals with autism. A dysfunctional execution/observation matching system has been proposed to account for this impairment. The EEG mu rhythm is believed to reflect an underlying execution/observation matching system. This study investigated evidence of differential mu rhythm attenuation during the observation, execution, and imitation of movements and examined its relation to behaviorally assessed imitation abilities. Fourteen high-functioning adults with autism spectrum disorder (ASD) and 15 IQ- and age-matched typical adults participated. On the behavioral imitation task, adults with ASD demonstrated significantly poorer performance compared to typical adults in all domains of imitation ability. On the EEG task, both groups demonstrated significant attenuation of the mu rhythm when executing an action. However, when observing movement, the individuals with ASD showed significantly reduced attenuation of the mu wave. Behaviorally assessed imitation skills were correlated with degree of mu wave attenuation during observation of movement. These findings suggest that there is execution/observation matching system dysfunction in individuals with autism and that this matching system is related to degree of impairment in imitation abilities.     

Cognitive processing impairments in a supra-second temporal discrimination task in rats with cerebellar lesion

The role of interpositus nuclei (IN) in timing in the sub-second range is well supported in eyeblink conditioning studies. Timing impairments shown in the seconds range in patients with intermediate cerebellar lesion, and known intermediate cerebellar cortex projection to IN raise the question of a possible involvement of IN in timing in the supra-second range as well. To address this question, we tested rats (Sprague-Dawley) given bilateral lesions of IN with Colchicine in a 2- vs. 8-s temporal discrimination task, followed by three daily sessions of a temporal bisection tests with five added intermediate non-reinforced durations. IN lesioned rats showed normal acquisition of the temporal discrimination, but a transient impairment of temporal sensitivity during the bisection tests. In addition, their response latencies suggested a different behavioral strategy from that of control animals. Our results indicate that the IN of the cerebellum may not be critically involved in temporal processing in the 2–8 s range, but may play a role in the cognitive processes that access temporal information in the mediation of choice behavior.