Cognitive substrates in semantic memory of formal thought disorder in schizophrenia

Formal thought disorder (FTD) has been associated with abnormalities in the semantic memory system. However, it is still unclear whether these abnormalities are related to the organization of the semantic system, or to the automatic spread of activation-inhibition in semantic networks. In this paper these alternative proposals are examined. Schizophrenic patients and healthy matched controls were given two semantic memory tasks. In the first task, participants were required to judge the similarity between pairs of natural concepts. These ratings are assumed to reflect the underlying knowledge organization. In the second task, participants were required to name pictures that were preceded by related or unrelated word primes. Interference is typically observed when pictures are preceded by semantically related primes, and it is explained as due to inhibitory processes from the word prime to the related picture target. The results showed that the semantic structures derived from the similarity ratings were similar for patients with and without FTD and for control participants. However, results from the picture-naming task indicated that both non-FTD and control participants showed the normal interference/inhibition effects from the related prime words, whereas the patients with FTD showed similar performance for pictures preceded by related words than for pictures preceded by unrelated words. These findings support the hypothesis that abnormalities in inhibitory processes in semantic memory underlie FTD.     

Associating semantic space abnormalities with formal thought disorder in schizophrenia: use of triadic comparisons

Recent studies of schizophrenia have suggested that thought disorder results from abnormalities in semantic processing. In the following pilot study, the cognitive system used for organizing and associating concepts was examined using a triadic comparison task. The semantic maps of schizophrenia patients with high thought disorder (N = 5) were compared to that of schizophrenia patients with low levels of thought disorder (N = 5) and normal controls (N = 10) with multidimensional scaling analysis. At initial testing and at retest, patients with high levels of thought disorder exhibited consistently lower semantic goodness of fit scores and failed to map results of triadic comparisons along well-defined dimensions. Results suggest that thought disorder in schizophrenia is related to a disturbance in the organization of semantic networks.     

Two new scales of formal thought disorder in schizophrenia

Information provided by patients and respective carers may help to understand formal thought disorder (FTD) in schizophrenia. Two scales, one for patients (FTD-patient) and one for carers (FTD-carer), were constructed to assess pragmatics, cognitive, paralinguistic, and non-verbal aspects of communication. In the first scale the patients themselves assess their verbal communication; in the second scale the carer assesses the speech of the respective patient. Both scales exhibited internal reliability and evidence of good test-retest reliability. Higher total scores on both scales (FTD-patient and FTD-carer) were significantly associated with positive FTD, but not with negative FTD. Principal component analysis of the scales yielded a multidimensional structure. It is suggested that FTD in schizophrenia may be associated with a range of deficits (e.g. pragmatics, lexical activation, working memory, sustained attention). These scales, in conjunction with the clinician's assessment, can provide a more comprehensive picture of FTD in schizophrenia, revealing its dimensions and making it possible to establish associations between symptoms of FTD and neuropsychological, neurophysiologic, and neuroimaging data. In addition, they provide service users' and carers' perspectives for the assessment of communication in schizophrenia.     

Cross-diagnostic comparison of visual processing in bipolar disorder and schizophrenia

Patients with Schizophrenia (SZ) show deficits across various stages of visual information processing. Whether patients with Bipolar Disorder (BD) exhibit these deficits is unclear. In this study, we conducted a detailed comparison of specific stages of early visual perception in BD and SZ. Forty-three BD patients, 43 SZ patients, and 51 matched healthy control subjects (HC) were administered three visual processing paradigms emphasizing: 1) an early stage of object formation (location backward masking), 2) a middle stage of object substitution (four-dot backward masking), and 3) a later stage at the perception–attention interface (rapid serial visual processing (RSVP) task eliciting the attentional blink). SZ performed significantly worse than BD and HC on location and four-dot masking. BD did not significantly differ from HC on either masking task. Both patient groups performed significantly worse than HC on the RSVP task; unlike SZ, BD did not show a significant attentional blink effect compared to HC. Our results indicate that BD patients were intact at the early and middle stages of visual processing (object formation and substitution) but intermediate between the SZ and HC groups at a later processing stage involving perceptual and attentional processes (RSVP task). These findings suggest that SZ is characterized by a diffuse pathophysiology affecting all stages of visual processing whereas in BD disruption is only at the latest stage involving higher order attentional functions.     

Working memory and semantic involvement in sentence processing: a case of pure progressive amnesia

ED, a 83-year-old woman, meets the criteria of pure progressive amnesia, with gradual impairment of episodic and autobiographical memory, sparing of semantic processing and strong working memory (WM) deficit. The dissociation between disturbed WM and spared semantic processing permitted testing the role of WM in processing anaphors like pronouns or repeated names. Results showed a globally normal anaphoric behavior in two experiments requiring anaphoric processing in sentence production and comprehension. We suggest that preserved semantic processing in ED would have compensated for working memory deficit in anaphoric processing.     

Meaningfulness and global-local processing in schizophrenia

The present work aimed to study the influence of the meaningfulness of stimuli during global-local processing in schizophrenia. Study participants were asked to determine whether pairs of compound stimuli (global forms composed of local forms) were identical or not. Both global and local forms represented either objects or non-objects. Results indicated that when identification processes were useful for performing the task, similar global-local response patterns were observed in patients and controls. However, patients were more affected than controls when an object was present at a distractor level, particularly when this information came from the local level. These results are discussed in terms of the conjunction of executive and visuospatial deficits and underscore the importance of meaningful identification in the visual perception of schizophrenia patients, given its central role in day-to-day situations.     

Information processing deficits of schizophrenic children with formal thought disorder

The relations among formal thought disorder, the partial report span of apprehension task, the distractibility factor on the Wechsler Intelligence Scale for Children-Revised (WISC-R), and IQ scores were examined in 31 schizophrenic children, aged 7.4 to 12.5 years. The partial report span of apprehension scores of the schizophrenic children correlated significantly with their illogical thinking scores. Their scores on loose associations were significantly associated with the WISC-R distractibility factor score. The attention/information processing deficits that might underlie the clinical manifestations of illogical thinking and loose associations in childhood onset schizophrenia are discussed.     

Attention/information processing, neuropsychological functioning, and thought disorder during the acute and partial recovery phases of schizophrenia: a longitudinal study

Schizophrenic subjects were administered the span of apprehension task, which is a measure of visual information processing; two neuropsychological tests; and measures of specific aspects of thought disorder and general clinical state. The measures were administered both when patients were acutely disturbed and when they were partially recovered. Normal control subjects were tested over a comparable 12-week interval. Improvements in both overall clinical condition and specific aspects of thought disorder occurred in the schizophrenic patients during this time. The patients, however, continued to show impaired information processing, indicating that the span of apprehension task is sensitive to schizophrenic dysfunction across wide variations in clinical state and, therefore, may be a marker of vulnerability to schizophrenia. The span of apprehension task was found to be significantly correlated with a measure of thought disorder that assesses resistance to associative distractors and two neuropsychological tests--the Trail-Making Test from the Halstead-Reitan battery and the Digit Symbol Substitution Test--during the testing session conducted while the subjects were partially recovered.     

Neurocognitive and social cognitive correlates of formal thought disorder in schizophrenia patients

The neurocognitive and social cognitive correlates of two types of formal thought disorder (i.e., bizarre-idiosyncratic and concrete thinking) were examined in 47 stable outpatients with schizophrenia. Both types of thinking disturbance were related to impairments in verbal learning, intrusions in verbal memory, immediate auditory memory, sustained attention, and social schema knowledge. Distractibility during an immediate memory task was associated with more frequent bizarre verbalizations but not concreteness. Impaired verbal learning rate and intrusions in verbal memory independently contributed to the prediction of bizarre responses, whereas intrusions in verbal memory and impaired immediate memory independently contributed to concrete thinking. This pattern of findings is consistent with the view that neurocognitive and, possibly, social cognitive deficits underlie these two aspects of formal thinking disturbance in schizophrenia.     

儿童思维形式障碍评估量表的修订及应用

目的 翻译及修订儿童思维形式障碍评估量表(kiddie formal thought disorder rating scale,K-FTDS),并应用于精神分裂症与非精神病性患儿.方法 将K-FTDS进行翻译及修订,并应用于27例精神分裂症和31例非精神病性患儿,评估一致性、特异性和敏感性.结果 K-FTDS的评定者间一致性(Kappa值)为0.71;当设置思维形式障碍总分界限值为0.0115时敏感性为0.852,特异性为0.935.精神分裂症患儿的思维形式障碍评分高于非精神病性患儿(z=565.5,P<0.01).结论 修订后的K-FTDS具有较好的评估者间一致性以及特异性、敏感性,可以用于儿童思维形式障碍的评估并鉴别精神分裂症患儿与非精神病性患儿.     

Cognitive disturbances in chronic schizophrenia: formal thought disorder and basic symptoms

We investigated 37 chronic schizophrenic patients with two objective rating scales (AMDP and Brief Psychiatric Rating Scale; BPRS) and compared the questioned symptoms with the Frankfurter Beschwerde Fragebogen (FBF), a questionnaire for subjective complaints which are close to the uncharacteristic 'basic' symptoms of schizophrenic patients. It was pointed out that the questions in the FBF relate mainly to uncharacteristic symptoms like disturbances of perception, concentration, attention, perceiving, and memory. These subjective symptoms of the FBF show a few correlations with the AMDP/BPRS rating. The total score of the FBF gave no further information about social functioning of patients with cognitive disturbances.     

Relation of formal thought disorder to symptomatic remission and social functioning in schizophrenia

ObjectiveThe aim of this cross-sectional study is to examine the relation of formal thought disorder (FTD) with symptomatic remission (SR) and social functioning in patients with schizophrenia.MethodThe study was carried out with a sample consisting of 117 patients diagnosed with schizophrenia according to DSM-IV. The patients were assessed with the Positive and Negative Syndrome Scale (PANSS), the Thought and Language Index (TLI), and the Personal and Social Performance Scale (PSP). We used logistic regression in order to determine the relation between FTD and SR and linear regression to identify the strength of association between FTD and social functioning.ResultsLogistic regression analysis revealed that poverty of speech (odds ratio: 1.47, p < 0.01) and peculiar logic (odds ratio: 1.66, p = 0.01) differentiated the remitted patients from the non-remitted ones. Linear regression analysis showed that the PSP total score was associated with poverty of speech and peculiar logic items of the TLI (B = −0.23, p < 0.01, B = −0.24, p = 0.01, respectively).ConclusionOur findings suggest that poverty of speech and peculiar logic are the specific domains of FTD which are related to both SR status and social functioning in patients with schizophrenia.     

Preferential semantic fluency impairment is related to hallucinations, but not formal thought disorder

Semantic memory dysfunction in schizophrenia spectrum disorders has been theoretically linked primarily to formal thought disorder (FTD) and, to a lesser extent, hallucinations. Although past studies have demonstrated associations between FTD and semantic memory dysfunction, the potential influence of hallucinations and other symptoms on this association has not previously been evaluated. We investigated the relationship between semantic dysfunction and levels of schizophrenic symptoms in 75 patients with a DSM-IV diagnosis of schizophrenia/schizoaffective disorder. Symptoms were rated on a 0-5 scale using the Scale for Assessment of Positive Symptoms/Scale for Assessment of Negative Symptoms. Semantic dysfunction was quantified through a semantic/phonological fluency difference score. The vocabulary test from the Shipley Institute of Living Scale was included as a measure of pre-morbid IQ. We hypothesized a relationship between FTD and semantic dysfunction, with an alternative hypothesis being that semantic dysfunction would be related to hallucinations. The measure of semantic dysfunction was significantly correlated with level of hallucinations (r=-.35, p=.002), but not level of FTD (r=.05, p=.67). The relationship between hallucinations and semantic dysfunction remained significant after control for age and verbal intellectual ability, and after controlling for the influence of other symptoms. This finding supports theories linking a breakdown in semantic associative networks to the production of hallucinations, and suggests that past associations between formal thought disorder and semantic dysfunction may have been at least partly driven by differential levels of hallucinations between groups.     

N400 anomalies in schizophrenia are correlated with the severity of formal thought disorder

We explored the link between N400 anomalies and clinical profile in schizophrenia patients. N400 was recorded in 50 schizophrenia patients and 40 healthy controls during a lexical decision task with semantic priming. Comparison between controls and schizophrenia patients showed the classical anomalies reported for N400 in schizophrenia patients: greater amplitude for related words and lack of N400 effect. Analyses of the correlations between N400 effect and various symptoms of schizophrenia (formal thought disorder, positive symptoms, negative symptoms, overall symptoms, mean neuroleptic dose) or socioeducational data (age, vocabulary level, number of years of study) revealed that only the correlation with formal thought disorder was significant: the higher the scores for formal thought disorder, the lower the N400 effect observed.     

青年和中年精神分裂症患者心理旋转信息加工系统研究

目的 探讨年龄因素对精神分裂症患者心理旋转信息加工系统的影响.方法 对78例精神分裂症患者,按不同年龄段将其分成两组,青年组38例,中年组40例,和76名(青年组36名,中年组40名)健康被试进行心理旋转任务的测定,测量其错误数和反应时.结果 (1)与对照组[(15.2±5.8)％]相比,患者组错误率升高[(42.8±7.6)％,P＜0.05].在对照组内,青年组正像和镜像错误率均低于中年组,差异有统计学意义(P＜0.05);在患者组内,青年组与中年组相比差异无统计学意义(P＞0.05).(2)与对照组[(744.3±93.1)ms]相比,患者组反应时升高[(947.8±97.8)ms,P＜0.05].在对照组内,青年组正像和镜像反应时均短于中年组,差异有统计学意义(P＜0.05);在患者组内,青年组与中年组相比差异无统计学意义(P＞0.05).(3)线性回归分析发现,对照组青年、中年组正镜像错误率、反应时均随着旋转角度递增呈线性递增函数(P＜0.001);患者组无此线性关系.结论 精神分裂症患者心理旋转信息加工机制受损,且年龄效应消失,其中青年受损程度大于中年患者.提示大脑神经系统的中年化在一定程度上能对心理旋转信息加工系统起保护作用.     

分裂症听感觉加工障碍与较高程度功能障碍的关系

目的 用失匹配负波(MMN)和P300去评定分裂症听信息加工中听感觉加工障碍与较高程度功能障碍的相关性.方法 52例分裂症患者和44例正常对照组采用事件相关脑电位检查,测量MMN和P300潜伏期和波幅,并采用SPSS和结构方程模型进行分析.结果 患者组产生的MMN的潜伏期、波幅与正常对照组比较差异有统计学意义(t=6.18,P＜0.01;t=2.42,P＜0.05),患者组产生的P300的波幅与正常对照组比较差异有统计学意义(t=2.64,P=0.01),患者组产生的P300的潜伏期与正常对照组比较差异无统计学意义(t=1.71,P＞0.05).结构方程模型评定显示Group(疾病过程)和MMN波幅及Group和P300波幅显示出有显著路径的内相关(B=-1.01,P=0.015;B=-0.60,P -0.039),MMN波幅与P300波幅显示出有显著路径的内相关(B=0.17,P=0.015).结论 分裂症听信息加工中听感觉加工的障碍直接影响着较高程度的功能障碍.