Biomedical subjects

M Blankenburg

Publications and source records attributed to M Blankenburg.

4 recordsLinked to original sources

PubMed1998

Target anticipation and impairment of smooth pursuit eye movements in schizophrenia.

A reduced gain of smooth pursuit eye velocity has frequently been reported in schizophrenic patients. With respect to predictable stimuli, this could be due to a deficit in predicting the target path. To determine this contribution to smooth pursuit eye movement performance, we analyzed the ocular smooth pursuit response to a sinusoidally moving target that was suddenly stopped after some cycles of regular movement. Horizontal eye movements were recorded with infrared reflection oculography in a group of 17 schizophrenic in-patients and 16 age-matched healthy subjects for controls. The patients exhibited a reduced gain of smooth pursuit velocity, but phase lag was not different from the control group. After the unpredictable stop of target movement, predictive sinusoidal smooth pursuit was maintained for 150 to 200 ms in both groups. The resulting maximal position and velocity error was larger in the patient group. In conclusion, schizophrenic patients were able to generate a normal anticipatory component of smooth pursuit and to switch it off in response to external demands. They showed, however, an increased velocity of anticipatory pursuit, which might be used to compensate for the primary deficit of smooth pursuit velocity frequently found in schizophrenics.

Adaptation, Physiological↗

PubMed1996

Treatment of irritable bowel syndrome with Lacteol Fort: a randomized, double-blind, cross-over trial.

OBJECTIVE: To assess the efficacy of Lacteol Fort, an antidiarrheal drug, in patients suffering from the chronic intestinal disease known as irritable bowel syndrome (IBS). DESIGN: The randomized, double-blind, cross-over trial versus placebo was carried out from 1992 to 1994. This trial consisted of administering a 6-wk treatment with a first drug (Lacteol Fort or placebo), followed by a wash-out period of 2 wk, and then the administration of a second drug for a further 6 wk (placebo or Lacteol Fort). Among the 29 patients eligible after recruitment, 18 adults with well documented IBS fulfilled the inclusion criteria. Four patients were dropped for loss of materials used in the study and seven for lack of compliance. The patient's initial state was assessed using a questionnaire relating to six criteria: abdominal pain, bloating or gas, daily number of stools, consistency, mucus content, and general physical state. During the treatment, these criteria were evaluated daily by the patients themselves. RESULTS: All investigated criteria were scored, and then a daily mean index was calculated. The statistical analysis of the daily mean index values showed that the number of patients (nine cases) obtaining better results with Lacteol Fort than with placebo was statistically significant (p = 0.018). CONCLUSIONS: This double-blind, placebo-controlled, cross-over trial demonstrated that Lacteol Fort leads to a statistically significant therapeutic benefit in 50% of patients, when taking into consideration all of the six selected clinical criteria considered representative of IBS.

Adult↗

PubMed1995

Cortical control of double-step saccades: implications for spatial orientation.

To accurately localize a visual target in space despite eye movement-induced shifts of its retinal image, the brain must take into account both its retinal location and information about current eye position or at least the preceding eye displacement. We examined this ability with respect to saccadic eye movements by applying "double-step" stimuli, where the locations of two sequentially flashed target lights have to be fixated by two successive saccades performed after their disappearance. As the 2nd saccade will not start at the spatial location from which the 2nd target was seen, a dissonance arises between its retinal coordinates and the motor coordinates of the required 2nd saccade. Nevertheless, these saccades were performed quite accurately by 32 healthy human adults. To investigate the contribution of the cerebral cortex, we recorded horizontal double-step saccades in 35 patients with focal unilateral hemispheric lesions. Whereas frontal lesions impaired temporal properties, posterior parietal lesions caused spatial dysmetria or failure of even ipsiversive 2nd saccades following contraversive 1st saccades. This reflects an inability to compensate for retinospatial dissonance by using nonretinal information (corollary discharge) about eye displacement associated with a previous saccade into the contralesional hemifield. In conclusion, the parietal cortex is crucial for spatial constancy across saccades.

Adult↗

PubMed1988

[Not Available].

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Germany↗