Electromyographic (EMG) recording was performed synchronously from the levator palpebrae superior... more Electromyographic (EMG) recording was performed synchronously from the levator palpebrae superioris (LP) and the orbicularis oculi (OO) muscles in 28 patients referred to us for treatment of blepharospasm with botulinum A toxin. At the time of this study, 19 patients were under the treatment with botulinum, four started treatment shortly after the EMG recording and five patients had not yet been treated. Based on the EMG patterns, we were able to classify five major groups of abnormalities. Group 1 (blepharospasm): consisted of 10 patients with dystonic discharges limited to OO, normal LP tonic activity, intact reciprocal inhibition between LP and OO and dense bursts of action potentials with high amplitude preceding the return of LP tonic activity, i.e. 'postinhibition potentiation' of LP, brought about by a brief contraction of OO. Group 2 (combined dystonic activities of LP and OO): seven patients belonged to this group. The EMG recording revealed alternating tremulous discharges in both LP and OO muscles, and short intervals of co-contractions due to moderately disturbed reciprocal inhibition. Group 3 (combination of blepharospasm, LP motor impersistence): the EMG patterns, observed in three patients, were characterized by a gradual cessation of LP activity, followed by a brief contraction of OO, which facilitated the return of LP activity, resulting in opening of the eyes. The EMG recordings, thus, revealed the crucial, beneficial role of postinhibition potentiation as a compensatory mechanism in this type of eyelid movement disorder. The EMG patterns were also characterized by short or prolonged periods of dystonic discharges limited to the OO muscles. Group 4 (combination of blepharospasm, involuntary LP inhibition): this group consisted of four patients. In addition to episodes of dystonic activities of OO, the EMG also showed some periods of involuntary inhibition of LP without any concomitant activities of OO. Two patients also exhibited a failure of inhibition of OO muscle activity, following the voluntary contraction of this muscle. The postinhibition potentiation was often not observed. Group 5 (involuntary LP inhibition): consisted of four patients with EMG patterns of involuntary inhibition of LP activity, without any dystonic discharges in OO. The postinhibition potentiation was not observed in this group. The response to the treatment with botulinum toxin was good in the first group and gradually worsened towards the fifth group. Application of botulinum into multiple sites of OO, especially its pretarsal portion, resulted in better response to the treatment in the second and fourth groups.(ABSTRACT TRUNCATED AT 400 WORDS)
Patients with schizophrenia consistently perform worse than healthy controls on the antisaccade t... more Patients with schizophrenia consistently perform worse than healthy controls on the antisaccade task in which the subject is required to inhibit a reflexive saccade to a suddenly appearing visual target and look in the opposite direction. To our knowledge there is no research yet showing how patients at ultra high risk (UHR) for developing psychosis perform on the antisaccade task. The aim of the present study was to investigate antisaccade task performance in UHR patients. Patients were eligible for the study when they met criteria for one or more of the following groups: Attenuated symptoms or brief limited intermitted psychotic symptoms or a first-degree family member with a psychotic disorder and reduced functioning or basic symptoms. In 35 UHR patients we assessed antisaccades, neuropsychological test performance and symptomatology. Antisaccade task results were compared with those obtained in 42 age- and intelligence-matched patients with recent-onset schizophrenia and 28 matc...
Prediction studies in subjects at Clinical High Risk (CHR) for psychosis are hampered by a high p... more Prediction studies in subjects at Clinical High Risk (CHR) for psychosis are hampered by a high proportion of uncertain outcomes. We therefore investigated whether quantitative EEG (QEEG) parameters can contribute to an improved identification of CHR subjects with a later conversion to psychosis. This investigation was a project within the European Prediction of Psychosis Study (EPOS), a prospective multicenter, naturalistic field study with an 18-month follow-up period. QEEG spectral power and alpha peak frequencies (APF) were determined in 113 CHR subjects. The primary outcome measure was conversion to psychosis. Cox regression yielded a model including frontal theta (HR=1.82; [95% CI 1.00-3.32]) and delta (HR=2.60; [95% CI 1.30-5.20]) power, and occipital-parietal APF (HR=.52; [95% CI .35-.80]) as predictors of conversion to psychosis. The resulting equation enabled the development of a prognostic index with three risk classes (hazard rate 0.057 to 0.81). Power in theta and delta ranges and APF contribute to the short-term prediction of psychosis and enable a further stratification of risk in CHR samples. Combined with (other) clinical ratings, EEG parameters may therefore be a useful tool for individualized risk estimation and, consequently, targeted prevention.
We investigated whether an index based on clinical features, electroencephalogram and computed to... more We investigated whether an index based on clinical features, electroencephalogram and computed tomography is useful to predict survival in early Alzheimer's disease. One hundred and sixty-three consecutively referred patients to an outpatient memory clinic and first diagnosed ...
Electromyographic (EMG) recording was performed synchronously from the levator palpebrae superior... more Electromyographic (EMG) recording was performed synchronously from the levator palpebrae superioris (LP) and the orbicularis oculi (OO) muscles in 28 patients referred to us for treatment of blepharospasm with botulinum A toxin. At the time of this study, 19 patients were under the treatment with botulinum, four started treatment shortly after the EMG recording and five patients had not yet been treated. Based on the EMG patterns, we were able to classify five major groups of abnormalities. Group 1 (blepharospasm): consisted of 10 patients with dystonic discharges limited to OO, normal LP tonic activity, intact reciprocal inhibition between LP and OO and dense bursts of action potentials with high amplitude preceding the return of LP tonic activity, i.e. 'postinhibition potentiation' of LP, brought about by a brief contraction of OO. Group 2 (combined dystonic activities of LP and OO): seven patients belonged to this group. The EMG recording revealed alternating tremulous discharges in both LP and OO muscles, and short intervals of co-contractions due to moderately disturbed reciprocal inhibition. Group 3 (combination of blepharospasm, LP motor impersistence): the EMG patterns, observed in three patients, were characterized by a gradual cessation of LP activity, followed by a brief contraction of OO, which facilitated the return of LP activity, resulting in opening of the eyes. The EMG recordings, thus, revealed the crucial, beneficial role of postinhibition potentiation as a compensatory mechanism in this type of eyelid movement disorder. The EMG patterns were also characterized by short or prolonged periods of dystonic discharges limited to the OO muscles. Group 4 (combination of blepharospasm, involuntary LP inhibition): this group consisted of four patients. In addition to episodes of dystonic activities of OO, the EMG also showed some periods of involuntary inhibition of LP without any concomitant activities of OO. Two patients also exhibited a failure of inhibition of OO muscle activity, following the voluntary contraction of this muscle. The postinhibition potentiation was often not observed. Group 5 (involuntary LP inhibition): consisted of four patients with EMG patterns of involuntary inhibition of LP activity, without any dystonic discharges in OO. The postinhibition potentiation was not observed in this group. The response to the treatment with botulinum toxin was good in the first group and gradually worsened towards the fifth group. Application of botulinum into multiple sites of OO, especially its pretarsal portion, resulted in better response to the treatment in the second and fourth groups.(ABSTRACT TRUNCATED AT 400 WORDS)
Patients with schizophrenia consistently perform worse than healthy controls on the antisaccade t... more Patients with schizophrenia consistently perform worse than healthy controls on the antisaccade task in which the subject is required to inhibit a reflexive saccade to a suddenly appearing visual target and look in the opposite direction. To our knowledge there is no research yet showing how patients at ultra high risk (UHR) for developing psychosis perform on the antisaccade task. The aim of the present study was to investigate antisaccade task performance in UHR patients. Patients were eligible for the study when they met criteria for one or more of the following groups: Attenuated symptoms or brief limited intermitted psychotic symptoms or a first-degree family member with a psychotic disorder and reduced functioning or basic symptoms. In 35 UHR patients we assessed antisaccades, neuropsychological test performance and symptomatology. Antisaccade task results were compared with those obtained in 42 age- and intelligence-matched patients with recent-onset schizophrenia and 28 matc...
Prediction studies in subjects at Clinical High Risk (CHR) for psychosis are hampered by a high p... more Prediction studies in subjects at Clinical High Risk (CHR) for psychosis are hampered by a high proportion of uncertain outcomes. We therefore investigated whether quantitative EEG (QEEG) parameters can contribute to an improved identification of CHR subjects with a later conversion to psychosis. This investigation was a project within the European Prediction of Psychosis Study (EPOS), a prospective multicenter, naturalistic field study with an 18-month follow-up period. QEEG spectral power and alpha peak frequencies (APF) were determined in 113 CHR subjects. The primary outcome measure was conversion to psychosis. Cox regression yielded a model including frontal theta (HR=1.82; [95% CI 1.00-3.32]) and delta (HR=2.60; [95% CI 1.30-5.20]) power, and occipital-parietal APF (HR=.52; [95% CI .35-.80]) as predictors of conversion to psychosis. The resulting equation enabled the development of a prognostic index with three risk classes (hazard rate 0.057 to 0.81). Power in theta and delta ranges and APF contribute to the short-term prediction of psychosis and enable a further stratification of risk in CHR samples. Combined with (other) clinical ratings, EEG parameters may therefore be a useful tool for individualized risk estimation and, consequently, targeted prevention.
We investigated whether an index based on clinical features, electroencephalogram and computed to... more We investigated whether an index based on clinical features, electroencephalogram and computed tomography is useful to predict survival in early Alzheimer's disease. One hundred and sixty-three consecutively referred patients to an outpatient memory clinic and first diagnosed ...
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