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Biomedical subjects

F Rist

Publications and source records attributed to F Rist.

At least 19 recordsLinked to original sources
PubMed2006

The Chemical Odor Sensitivity Scale: reliability and validity of a screening instrument for idiopathic environmental intolerance.

OBJECTIVE: The objective of this study was to examine the psychometric qualities of a brief screening measure for idiopathic environmental intolerance (IEI), the Chemical Odor Sensitivity Scale (COSS). METHODOLOGY: The COSS was administered together with other measures of environmental sensitivity, IEI, and symptom scales in large samples (students, individuals with IEI, and individuals without IEI). RESULTS: The COSS achieved high internal consistency (.88 < or = Cronbach's alpha < or = .96) and good factorial, convergent, and discriminant validity across diverse samples. In a longitudinal sample, the COSS and other IEI features were stable across time. According to receiver operating characteristic analyses, the COSS performs adequately in screening individuals likely to meet case criteria for IEI. CONCLUSIONS: The favorable psychometric qualities of the COSS recommend the scale as a useful tool both for assessing self-reported chemical odor sensitivity as a vulnerability marker and for screening for IEI.

Adolescent↗
PubMed2004

[Is premature termination of opiate detoxification due to intensive withdrawal or craving?].

Opiate addicts terminate inpatient detoxification prematurely in about 50% of treatment episodes. Premature termination of treatment is often considered to be motivated by intensive withdrawal symptoms. Therefore, the relation between discontinuing treatment and the intensity of withdrawal symptoms and heroin craving is investigated. 130 opiate addicts consecutively admitted to a detoxification ward daily assessed the intensity of withdrawal symptoms on the Short Opiate Withdrawal Scale (SOWS) as well as the intensity of heroin craving on a visual analogue scale. Withdrawal symptoms were treated by stepwise reduction of methadone and symptom-oriented medication. 66 patients (50.8%) terminated treatment prematurely. However, during the days preceding treatment termination, these patients did not differ from regularly detoxified patients assessed on corresponding days with respect to craving, and reported even less intensity of withdrawal symptoms. In conclusion, neither the intensity of withdrawal symptoms nor the intensity of heroin craving constitutes the primary reason for premature termination of detoxification.

Adolescent↗
PubMed2004

Effects of improved glycaemic control maintained for 3 months on cognitive function in patients with Type 2 diabetes.

BACKGROUND AND AIM: In a previous study we failed to find beneficial short-term effects of improved glycaemic control on cognitive functioning in patients with Type 2 diabetes mellitus. A subgroup of the entire sample was tested again to examine the effect of longer-lasting improvement of metabolic control on cognitive functioning. METHODS: The cognitive performance of 26 patients with Type 2 diabetes was assessed at baseline and 3 months after discharge. Thirteen controls were tested at the similar time-points. Attention/concentration, psychomotor speed, verbal fluency, verbal memory and depressive symptoms were assessed. Improved glycaemic control was generally achieved with insulin therapy (20/26). RESULTS: At baseline, there was a trend for diabetic patients to perform worse than controls. Both groups improved significantly over 3 months in several measures. However, diabetic patients did not improve more than controls. CONCLUSIONS: In individuals with long-standing Type 2 diabetes, previous reports of improved cognitive capacity following restoration and maintenance of near-normoglycaemia were not confirmed. This might relate to the type of anti-diabetic therapy.

Blood Glucose↗
PubMed2003

[Ill due to amalgam? 10 rules for managing the symptomatic patient].

Over the past two decades, mercury released by amalgam fillings has been held responsible for a number of mental and somatic health complaints. However, a systematic relation between increased mercury levels and the severity of the reported symptoms has never been demonstrated in any of the present well-controlled multidisciplinary studies. These studies, however, have found a high prevalence of mental disorders, especially somatization syndromes, among patients with self-diagnosed "amalgam illness". Additionally, our own studies indicate that amalgam anxiety is often merely one aspect of a general environmental anxiety. Overall, the present findings suggest a psychological etiology for amalgam-related complaints. Our psychosomatic model of "amalgam illness" integrates external factors, individual predispositions and specific processes of perception, awareness, evaluation and attribution. Practical management strategies for primary care physicians can be derived from this model.

Dental Amalgam↗
PubMed2001

Adverse health effects related to mercury exposure from dental amalgam fillings: toxicological or psychological causes?

BACKGROUND: Possible adverse health effects due to mercury released by amalgam fillings have been discussed in several studies of patients who attribute various symptoms to the effects of amalgam fillings. No systematic relation of specific symptoms to increased mercury levels could be established in any of these studies. Thus, a psychosomatic aetiology of the complaints should be considered and psychological factors contributing to their aetiology should be identified. METHODS: A screening questionnaire was used to identify subjects who were convinced that their health had already been affected seriously by their amalgam fillings (N = 40). These amalgam sensitive subjects were compared to amalgam non-sensitive subjects (N = 43). All participants were subjected to dental, general health, toxicological and psychological examinations. RESULTS: The two groups did not differ with respect to the number of amalgam fillings, amalgam surfaces or mercury levels assessed in blood, urine or saliva. However, amalgam sensitive subjects had significantly higher symptom scores both in a screening instrument for medically unexplained somatic symptoms (SOMS) and in the SCL-90-R Somatization scale. Additionally, more subjects from this group (50% versus 4.7%) had severe somatization syndromes. With respect to psychological risk factors, amalgam sensitive subjects had a self-concept of being weak and unable to tolerate stress, more cognitions of environmental threat, and increased habitual anxiety. These psychological factors were significantly correlated with the number and intensity of the reported somatic symptoms. CONCLUSIONS: While our results do not support an organic explanation of the reported symptoms, they are well in accord with the notion of a psychological aetiology of the reported symptoms and complaints. The findings suggest that self-diagnosed 'amalgam illness' is a label for a general tendency toward somatization.

Adult↗
PubMed2001

Implicit memory in schizotypal subjects and normal controls: effects of a secondary task on sequence learning.

Using a serial reaction-time task, the implicit memory performances of 29 high scoring (schizotypes) and 24 low scoring subjects (controls) on the German version of the 1997 Schizotypal Personality Questionnaire by Klein, Andresen, and Jahn were compared. To test the hypothesis that schizotypes show a differential deficit, subjects participated either in a single task condition of the serial reaction-time task or in a dual task condition of a secondary tone-counting task. Neither under single task conditions nor under dual task conditions did schizotypes show any impairment of implicit memory compared with controls. In addition, a separate analysis of the response latencies for the unique and ambiguous transitions of the repeated sequence did not indicate any differences between the two groups. These findings support and augment the results reported by Ferraro and Okerlund (1995).

Adolescent↗
PubMed1999

An event-related brain potential substrate of disturbed response monitoring in paranoid schizophrenic patients.

Response monitoring in schizophrenic patients and healthy controls was assessed by measuring performance and event-related brain potentials in the flanker priming task. Three visual-context conditions were construed: Flankers and targets pointed either into the same direction or into different directions. Stimuli without any response assignment were used as flankers in the neutral context condition. The schizophrenic patients were further subdivided into paranoid (n = 19) and nonparanoid (n = 10) patients and compared with healthy controls (n = 18). Performance scores revealed that the flankers induced a similar degree of distraction by visual context in all 3 groups. Although the schizophrenic patients showed normal error correction performance, the error negativity (NE) was significantly reduced in paranoid schizophrenic patients. The attenuation of the NE possibly reflects disturbed response monitoring in these patients.

Adult↗
PubMed1996

N2, P3 and the lateralized readiness potential in a nogo task involving selective response priming.

Motor inhibition and its correlates in the event-related potential (ERP) are often studied in go/nogo tasks. However, go and nogo trials differ in their motor and their attentional requirements, rendering an interpretation of corresponding changes in ERP components difficult. As an alternative strategy to study motor inhibition, a hybrid choice-reaction go/nogo procedure involving selective response priming was used. Eighteen subjects performed the task. Response time (RT) and error measures as well as the lateralized readiness potential (LRP) indicated that responses were primed by flanker stimuli that were associated with one of the two possible responses. In nogo trials, selective response priming influenced the N2 amplitude whereas the P3 amplitude was unaffected. Because the N2 appeared irrespective of whether an erroneous response was correctable (in go trials) or not (in nogo trials), we conclude that the N2 reflects either the detection or the inhibition of an inappropriate tendency to respond.

Adult↗
PubMed1996

N200 in the flanker task as a neurobehavioral tool for investigating executive control.

Event-related potentials were recorded in a flanker task using arrowheads pointing to the left or to the right as targets and as congruent or incongruent flanker stimuli using squares as neutral flanker stimuli. The onset of the flanker stimuli preceded that of the target stimuli by 100 ms. Lateralized readiness potentials showed response activation below execution threshold in correspondence to the information conveyed by the flanker stimuli. Exclusively, the incongruent flanker condition provoked a N2c, which evolved closely synchronized to the erroneous response. Graded response analyses separating incongruent trials with weak, medium, and strong incorrect response activation revealed that the N2c amplitude covaried with the magnitude of the erroneous response. The N2c in the incongruent compatibility condition of the flanker task thus corresponds to the avoidance of inappropriate responses, possibly reflecting the inhibition of automatically but erroneously primed responses. The results are compatible with studies of error correction, suggesting that efference monitoring is a constituent of executive control.

Adult↗
PubMed1994

Patient Rejection Scale: correlations with symptoms, social disability and number of rehospitalizations.

The Patient Rejection Scale (RPS), which was developed to assess rejecting attitudes and feelings of relatives toward mental patients, was administered to a German sample of 44 family members or significant others living with first-admitted schizophrenics. Both at admission (t0) and 6 months later (t6), the PRS was significantly correlated with the number of rehospitalizations during the first 3 years after admission. In comparison, the association between PRS scores and different measures of psychopathology during the 2-year follow-up period was weak. Thus, rejecting attitudes of patients' relatives seem to imply a higher risk of relapse without substantial medication by symptoms. We suspect that relatives with rejecting attitudes towards a patient might tend to apply for readmission more easily than more accepting relatives.

Adolescent↗
PubMed1994

Selective attention and response competition in schizophrenic patients.

Visual distractibility was studied in schizophrenic patients. Subjects had to respond to target stimuli while they ignored the visual context, which was either congruent, neutral, or incongruent with respect to the target stimulus. Eighteen schizophrenic patients and 18 healthy subjects performed this flanker task. Schizophrenic patients did not show increased distractibility compared with healthy subjects, and both groups showed the same attenuation of visual context effects when the spatial distance between target and flanker stimuli was increased. The two groups showed the same amount of interference by incongruent visual context. Thus, schizophrenic patients did not show enhanced distractibility, spatial extension of attention, or response competition. When flanker and target stimuli were redundant, the responses of schizophrenic patients were less accelerated than those of healthy subjects.

Adult↗
PubMed1994

Error-correcting behavior in schizophrenic patients.

According to Frith (1987) the positive symptoms of schizophrenic patients result from an impaired central monitoring of their own actions. For motor behavior, this impairment implies deficient corrections of erroneous movements. Several studies found that schizophrenic patients did correct erroneous movements less frequently than various control groups. In these studies, movement errors were induced by instructing subjects to alternate between moving a joystick towards a target or away from it. In our study, 27 chronic schizophrenic patients, 27 healthy and 18 alcoholic controls were subjected to a similar task. Spatial and symbolic compatibility between stimuli and responses were varied in order to induce errors. Schizophrenic patients responded more slowly and took more time to reverse wrong movements than both control groups. They did not show fewer error corrections or increased correction latencies. These results did not support the supposed deficit in central monitoring of action. Schizophrenic patients exhibited more short latency movements with multiple changes of movement direction than the control groups. This may indicate a failure to inhibit the initiation of competing responses.

Adult↗
PubMed1994

Reaction time paradigms in subjects at risk for schizophrenia.

Deviant response patterns in experimental reaction time paradigms in schizophrenic probands are well documented. Although simple reaction times are strongly influenced by the current psychopathological status of the proband (e.g. florid psychotic patients versus remitted patients) these influences are less clear for measures obtained from more complex reaction time paradigms. These include the crossover paradigm (reaction time to stimuli presented after constant preparatory intervals in comparison to reaction time to stimuli presented after irregular preparatory intervals) and the modality shift paradigm (reaction time to a stimulus (light or tone) when the modality of the stimulus on the preceding trial was the same compared to when it was different). It is not clear if these peculiarities of response patterns occur as a consequence of the disease or if they represent vulnerability markers for schizophrenia. Both crossover reaction time and modality shift reaction time paradigms were applied to 56 drug free schizophrenics, 45 healthy siblings of these patients and 68 healthy controls. The results indicate that retarded reaction times and the occurrence of the crossover effect as well as of the modality shift effect distinguish schizophrenics and controls. Healthy siblings of schizophrenics differed from healthy controls with regard to the crossover effect but not with regard to the modality shift effect. Therefore only the crossover effect represents a vulnerability marker for schizophrenia. Correlations between the modality shift and the crossover effect revealed strong correlations in the schizophrenic group only.

Adolescent↗
PubMed1992

Neuropsychological indicators of the vulnerability to schizophrenia.

Schizophrenia is associated with enduring deficits in neuropsychological functioning. It is widely undecided if the various aspects of neuropsychological impairment are a consequence of the disorder or if they are also present premorbidly and in populations at increased risk for schizophrenia (vulnerability markers). Neuropsychological deficits in healthy relatives of schizophrenic patients who are at an elevated risk for schizophrenia and who did not yet pass the period of risk would indicate that these deficits are vulnerability markers. This hypothesis was tested for three neuropsychological paradigms which have been proven to distinguish schizophrenic patients from controls. 33 siblings of drug-free schizophrenic probands revealed deficits has compared to 33 matched healthy controls in a blurred single target version of the Continuous Performance Test and in a multiple item version of the Span of Apprehension Test but not so in less difficult versions of both tests or in the time needed to react to stimuli with shifting modality.

Adult↗
PubMed1988

Placebo injections and surveillance of alcohol intake during inpatient treatment of female alcoholics.

Institutions for treating alcoholics differ widely with respect to how restrictively they apply psychopharmacological agents and how rigorously they control patients for intake of alcohol. This study investigates the impact of such policies on relapse rates. During a three month inpatient treatment, 70 female alcoholics were assigned to one of four conditions: (a) strict surveillance of alcohol intake by means of breath tests and frequent checks of patient's rooms as well as injections of a placebo purportedly reducing craving, (b) no surveillance but placebo injections, (c) surveillance but no placebo injections, and (d) neither surveillance nor placebo injections. The amount of surveillance did not influence relapse rates. However, during inpatient treatment more relapses occurred among patients who received the placebo injections than among those who did not. Although this effect was no longer significant following treatment, the increase of relapse rates suggests caution in the application of nonspecific medication in the treatment of alcoholics.

Adult↗
PubMed1986

The patient rejection scale: cross-cultural consistency.

The Patient Rejection Scale, which was developed to assess rejecting feelings of family members toward mental patients, was administered to a sample of 80 relatives living with schizophrenic patients in the Federal Republic of Germany. In spite of the cross-cultural differences involved, the response distributions of the German sample and a New York City sample of families were almost identical. The findings are discussed in the context of "expressed emotions" research.

Adolescent↗