Biomedical subjects

Peter Trillenberg

Publications and source records attributed to Peter Trillenberg.

5 recordsLinked to original sources

PubMed2006

Evidence from increased anticipation of predictive saccades for a dysfunction of fronto-striatal circuits in obsessive-compulsive disorder.

In obsessive-compulsive disorder (OCD), a dysfunction of neuronal circuits involving prefrontal areas and the basal ganglia is discussed that implies specific oculomotor deficits. Performance during reflexive and predictive saccades, antisaccades and predictive smooth pursuit was compared between patients with OCD (n=22), patients with schizophrenia (n=21) and healthy subjects (n=24). Eye movements were recorded by infrared reflection oculography. In both patient groups, higher frequencies of anticipatory saccades with reduced amplitudes in the predictive saccade task were observed. Additionally, reduced smooth pursuit eye velocity and increased frequencies of saccadic intrusions during smooth pursuit as well as increased error rates in the antisaccade task were demonstrated for patients suffering from schizophrenia. Patients with OCD and schizophrenia revealed different patterns of oculomotor impairment: whereas increased anticipation of predictive saccades provides evidence for a dysfunction of the circuit between the frontal eye field and the basal ganglia in both groups, results from the antisaccade task imply additional deficits involving the dorsolateral prefrontal cortex in schizophrenic patients. Furthermore, the cortical network for smooth pursuit (especially the frontal eye field) is also assumed to be disturbed in schizophrenia.

Adult↗

PubMed2006

Eye-hand coordination in essential tremor.

Patients with essential tremor (ET) or with cerebellar lesions have in common oculomotor abnormalities, with the exception of saccadic eye movements, which do not seem to be involved in ET. Since grasping is prolonged in ET and might be related to saccadic dysmetria, we tested whether simultaneous hand pointing could unmask it. Twelve ET patients and 14 controls performed saccades with and without simultaneous pointing movements to the same targets, and with and without a gap between the disappearance of the fixation point and the appearance of the target. Eye movements were recorded with the magnetic search-coil method, hand movements with an ultrasound-emitting probe. ET patients did not have saccadic dysmetria, and contrary to normal subjects their saccadic latency did not decrease during combined eye-hand movements compared with saccades performed in isolation. Hand movements had a longer duration in ET patients, with decreased peak acceleration, an increased latency of the peak velocity, and peak deceleration. In conclusion, this first study on eye-hand coordination in ET revealed abnormal kinematic changes in the early phase of pointing movements. These changes might be related to cerebellar disease but they are independent of the intention tremor component and saccade performance.

Adult↗

PubMed2004

Botulinum toxin as an effective treatment of clozapine-induced hypersalivation.

Hypersalivation is a common and frequently disabling side effect of atypical neuroleptics such as clozapine. Current treatment options of this adverse advent are limited by lack of efficacy or additional side effects. Botulinum toxin (BTX) injections into the parotid glands have been shown to be very effective in treating sialorrhea in the context of various neurological disorders, such as Parkinson's and motor neuron disease. Surprisingly, BTX treatment of drug-induced sialorrhea has not yet been described. We here report a patient with clozapine-induced hypersalivation and a good response to BTX injections lasting for more than 12 weeks, resulting in a marked reduction of the hypersalivation and consequently of his social withdrawal. Our patient serves to alert clinicians to the frequent problem of drug-induced sialorrhea and suggests that BTX injections should be considered as an effective and safe treatment for hypersalivation in psychiatric patients treated with clozapine.

Anti-Dyskinesia Agents↗

PubMed2004

On the role of the cerebellum in exploiting temporal contingencies:; evidence from response times and preparatory EEG potentials in patients with cerebellar atrophy.

Patients with degenerative cerebellar disease were compared to healthy controls in their ability to adapt behaviour to temporal contingencies, both according to instructions and according to acquired experience. Participants had to press the cued key whenever the inside of a clock face changed its colour, which could occur when the pointer, rotating once every 4s, was at "10h" or at "12h" or at "2h". Probabilities varied between blocks at which of these three time points the colour change occurred, with participants being instructed accordingly. Response times correlated intraindividually with these instructed "a priori" probabilities in control participants only. Subjectively, at any moment, probabilities of occurrence depend on whether the imperative colour change had occurred before, thus may be better described by conditional ("a posteriori") probabilities. Indeed, when response times were correlated to a posteriori rather than a priori probabilities, correlations increased in both groups equally from their different a priori levels. The amplitudes of preparatory EEG negativity before responding tended to obey to the same relationships, suggesting that the difference between groups was not due to pure motor impairment. Thus, these data suggest that patients with cerebellar atrophy are more impaired in implementing and using task-relevant information in a top-down manner than in learning to modify task-relevant contingencies.

Adult↗

PubMed2004

Eye movements and psychiatric disease.

PURPOSE OF REVIEW: During the past year a number of studies have been published on eye movement dysfunction in patients with psychiatric disease. According to the mainstream of modern neuropsychiatric research, these studies cover either genetic aspects or the results of pharmacological manipulation. RECENT FINDINGS: A few studies addressed impaired smooth pursuit eye movements (eye tracking dysfunction) in unaffected relatives of psychiatric patients, and were important in excluding non-specific effects (e.g. medication) and isolating genetic predisposition to the disease. This predisposition could be demonstrated in families of schizophrenic patients irrespective of whether the index case was sporadic or familial. One large study demonstrated pathological distributions of various parameters of smooth pursuit eye movement performance in groups of schizophrenic patients and their relatives. However, another study challenged the specificity of eye tracking dysfunction as a trait marker for schizophrenia by showing that its prevalence was identical among relatives of patients with affective disorder and schizophrenia. Eye tracking dysfunction was associated with two gene polymorphisms that interfere with dopamine metabolism and are thus reasonable candidate genes for the predisposition to schizophrenia. The influence of nicotine and neuroleptic drugs on eye movement performance was studied in schizophrenic patients. Nicotine improved smooth pursuit performance in three studies, one of which attributed this finding to enhanced attention. Two groups of schizophrenic patients treated with two different atypical neuroleptic drugs, risperidone and olanzapine, did not differ in a battery of saccadic tasks. SUMMARY: Eye movements provide an important tool to measure pharmacological effects in patients and unravel genetic traits in psychiatric disease.

Dopamine↗