Schizophrenia impairs phonological speech production: a preliminary report.

INTRODUCTION: Schizophrenia causes clinically conspicuous impairment of syntax and semantics as part of the disorganisation syndrome; however, little is known regarding its effect on the phonological stage of speech, where word meanings are resolved into speech imagery. METHODS: We used a "tongue-twister" task to probe phonological speech production and its clinical associations in six schizophrenia patients and 16 controls. RESULTS: Errors induced by phonological similarity were more common in the patients (p=.003), were positively associated with psychomotor poverty symptoms (p=.02) and negatively associated with reality distortion symptoms (p=.03). CONCLUSIONS: Our findings suggest that phonological speech production is markedly disrupted by schizophrenia. Further, this phonological abnormality is distinct from disorganisation syndrome.

Time perception and its neuropsychological correlates in patients with schizophrenia and in healthy volunteers.

Disordered time perception has been reported in schizophrenia. We investigated time perception dysfunction and its neuropsychological correlates in patients with schizophrenia. Participants comprised 38 patients and 38 age- and sex-matched healthy volunteers who were compared in an auditory temporal bisection paradigm using two interval ranges (a 400/800 ms condition and a 1000/2000 ms condition). In the temporal bisection, subjects were required to categorise a probe duration as short or long, based upon the similarity with two reference durations. All subjects also completed a battery of neuropsychological tests measuring sustained attention, short- and long-term memory and executive function. In the 400/800 ms condition, patients judged durations significantly shorter than did control subjects. Patients also exhibited decreased temporal sensitivity in both conditions. We found in both groups a negative association between temporal sensitivity and sustained attention for the 400/800 ms condition, and between temporal sensitivity and long-term memory for the 1000/200 ms condition. In patients, short-term memory performance was negatively associated with duration judgement in both conditions, while executive dysfunction was correlated to a general performance deficit in the 400/800 ms condition. These findings suggest the possibility that time perception abnormalities in schizophrenia are part of neuropsychological dysfunction and are likely to adversely impact upon activity of daily living.

Voice familiarity engages auditory cortex.

Familiarity with a speaker's voice has been shown to enhance its auditory processing, implicating physiological effects at the level of the auditory cortex, although auditory cortical involvement has not previously been demonstrated. Eleven healthy right-handed male participants performed two tasks during blood oxygenation level-dependent functional MRI at 1.5 T. Both tasks used the same vocal stimuli. In task 1, they classified speakers as familiar or unfamiliar. In task 2, they judged stimuli as being in the right or left auditory field. Our analysis showed an area of auditory cortex on the lower bank of the superior temporal sulcus that was preferentially activated by familiar voices in both tasks. Familiar voices may elicit access to detailed sensory expectations, allowing enhanced auditory cortical processing.

Control of attention in schizophrenia.

The deficits of attention contribute significantly to the clinical picture of functional disability seen in schizophrenia, but there is no consensus as to whether this cognitive function can be fractionated to allow further characterisation of the impairment. We examined fifteen patients with chronic schizophrenia and fifteen controls using paired tasks designed to measure four hypothetical aspects of attentional control: the ability to focus attention, to resist distraction, to shift attention, and to divide attention. The group with schizophrenia showed a significant improvement in accuracy on a digit span repetition task when a simultaneous box-crossing task was added (divided attention condition). Although the patient group showed impaired performance across nearly all of the tasks, they were not disproportionately impaired during the task conditions assumed to demand greater attention. These results suggest that the aspects of attention and executive function under study are not significantly affected by schizophrenia and indicate the need for further characterisation of the impairment usually reported using conventional tests of attention on those with schizophrenia.

Hodological resonance, hodological variance, psychosis, and schizophrenia: a hypothetical model.

Schizophrenia is a disorder with a large number of clinical, neurobiological, and cognitive manifestations, none of which is invariably present. However it appears to be a single nosological entity. This article considers the likely characteristics of a pathology capable of such diverse consequences. It is argued that both deficit and psychotic symptoms can be manifestations of a single pathology. A general model of psychosis is proposed in which the informational sensitivity or responsivity of a network ("hodological resonance") becomes so high that it activates spontaneously, to produce a hallucination, if it is in sensory cortex, or another psychotic symptom if it is elsewhere. It is argued that this can come about because of high levels of modulation such as those assumed present in affective psychosis, or because of high levels of baseline resonance, such as those expected in deafferentation syndromes associated with hallucinations, for example, Charles Bonnet. It is further proposed that schizophrenia results from a process (probably neurodevelopmental) causing widespread increases of variance in baseline resonance; consequently some networks possess high baseline resonance and become susceptible to spontaneous activation. Deficit symptoms might result from the presence of networks with increased activation thresholds. This hodological variance model is explored in terms of schizo-affective disorder, transient psychotic symptoms, diathesis-stress models, mechanisms of antipsychotic pharmacotherapy and persistence of genes predisposing to schizophrenia. Predictions and implications of the model are discussed. In particular it suggests a need for more research into psychotic states and for more single case-based studies in schizophrenia.

Neurocognitive basis of insight in schizophrenia.

People with schizophrenia have been categorised into three groups: those with full insight (aware, correct attributers); those aware of being unwell, but who misattributed their symptoms (aware, incorrect attributers); and those unaware of being ill (unaware). Cluster analysis of 'awareness of illness'and 'relabelling of symptoms'scores on the Schedule for the Assessment of Insight confirmed three distinct subgroups. The unaware group were impaired on executive and memory tests, whereas those in the aware, misattributing group were cognitively intact. Findings support an association between unawareness of illness and executive dysfunction, and highlight the separation of symptom misattribution from unawareness of illness.

Executive dysfunction screening test for neuropsychiatric disorders.

The Analogies Understanding Test (AUT) was developed as a brief cognitive screening task of executive problem solving. A few of the test items at the beginning are "facilitated" as a means of engaging patients. Individuals with schizophrenia and mild Alzheimer's Disease (AD) made significantly less correct responses than their control groups. The schizophrenia patients, but not AD patients, made significantly more perseverations than controls on the AUT. As expected, AUT performance in schizophrenia patients correlated with the Wisconsin Card Sorting test measures. Preliminary findings suggest that the AUT test may be useful as a measure of executive dysfunction in neuropsychiatric patients.

Voltammetric characterization of C60(PhX)2 (X = H, Br) and digital simulation of their electrochemically-induced reactivity.

The electrochemistry of two new 1,7-diaryl C(60) phenylated derivatives is explored in THF at various temperatures (from 25 to -90 degrees C). While at room temperature their voltammetric response is that typically shown by fairly stable species, when the temperature drops a very high electrochemically induced reactivity is evidenced. The investigation of the voltammetric patterns supported by an extensive use of digital simulation techniques finally led to the formulation of a reaction mechanism that includes electrochemically-induced migration of the phenyl groups as a possible explanation of the observed behavior.

Clinical and service implications of a cognitive analytic therapy model of psychosis.

Cognitive analytic therapy (CAT) is an integrative, interpersonal model of therapy predicated on a radically social concept of self, developed over recent years in the UK by Anthony Ryle. A CAT-based model of psychotic disorder has been developed much more recently based on encouraging early experience in this area. The model describes and accounts for many psychotic experiences and symptoms in terms of distorted, amplified or muddled enactments of normal or 'neurotic' reciprocal role procedures (RRPs) and of damage at a meta-procedural level to the structures of the self. Reciprocal role procedures are understood in CAT to represent the outcome of the process of internalization of early, sign-mediated, interpersonal experience and to constitute the basis for all mental activity, normal or otherwise. Enactments of maladaptive RRPs generated by early interpersonal stress are seen in this model to constitute a form of 'internal expressed emotion'. Joint description of these RRPs and their enactments (both internally and externally) and their subsequent revision is central to the practice of CAT during which they are mapped out through written and diagrammatic reformulations. This model may usefully complement and extend existing approaches, notably recent CBT-based interventions, particularly with 'difficult' patients, and generate meaningful and helpful understandings of these disorders for both patients and their treating teams. We suggest that use of a coherent and robust model such as CAT could have important clinical and service implications in terms of developing and researching models of these disorders as well as for the training of multidisciplinary teams in their effective treatment.