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Contingent negative variation (CNV) in mood disorders
Society Proceedings
This corpus of data suggests that EPs might be useful to study the mechanisms of attentional disorders, the only reservation being that some of the above findings reach statistical significance in group, but not in individual, studies.
4. Event-related France)
desynchronization.
-
J.D.
Guieu
(C.H.R.
Lille,
Title only.
5. Cognitive function and the P300 event-related potential in epileptic patients in normal conditions and before and after sleep deprivation. - P.E.H. Van Nunen and A.C. Declerck (Heeze, The Netherlands)
Disturbances in attention and alertness are common complaints in patients suffering from epilepsy and are hard to measure objectively. The P300 component of the event-related brain potential seems to be an objective measurement of these cognitive functions. In a pilot study we found that P300 latency was prolonged in patients with epileptic seizures compared to controls. In the next study 48 patients with complex partial epilepsy (CPE) were assigned to 4 groups: (I) without medication, (2) a monotberapy of carbamazepine (CBZ). (3) a polytherapy including CBZ, (4) a polytherapy without CBZ. P300 latency and amplitude were compared to a control group (N = 11). We found the largest prolongation of P300 latency and the smallest amplitude in the CPE group without medication. Only the CPE group with a polytherapy including CBZ had normal latencies and amplitudes. We concluded that the disorder in brain function that caused their seizures also caused the cognitive impairment as measured by the P300. To determine the effects of I night of total sleep deprivation as well as the value of a 2-3 h long sleep compensation we performed another experiment. Epileptic patients came to our clinic for I night of total sleep deprivation followed by a compensatory period in the morning. Patients had to perform in an auditory oddball paradigm prior to sleep deprivation, immediately prior to the morning sleep, and again after being awakened. Preliminary results (N = 17) showed no differences in P300 latencies and amplitudes. These results suggest that biological influences such as sleep deprivation, which is a very provocative situation, and a compensatory sleep period have no effect on latency and amplitude of the P300. Thus whenever latency of the P300 is prolonged or its amplitude decreased there must be a disorder in cognitive function.
6. Neuropsychology pital, Ghent)
of eye movements.
- L. Crevits (University
Hos-
Numerous cortical and subcortical areas are involved in the control of eye movements. Only the visually guided saccadic system will be considered in the present review. All these saccades are triggered through two cortical poles, the frontal eye field (FEF) and the posterior parietal cortex (PPC>. The PPC is mainly concerned with reflexive saccades. No required reflexive saccades are inhibited by the prefrontal cortex. The FEF is principally involved in intentional saccades. Memory guided saccades are controlled successively by the PPC (visuospatial integration), the prefrontal cortex (spatial memorization). the supplementary motor cortex (temporal memorization), and the FEF (triggering). The parietal pole, especially on the right, seems to be essential for disengagement of spatial selective attention, the prefrontal region for maintenance of visual attention. Saccades are permitted if visual attention is disengaged, they are inhibited if attention is maintained (fixation). Subcortical area such as the basal ganglia and the thalamus are important relays in the cortico-subcortical circuits of both the saccadic
and the attentional systems. Finally, the superior colliculus role in visuo-oculomotor coordination,
109P
plays a crucial
7. The role of parietal cortex in control of attention to a peripheral target used in discrimination: evidence from PET. - G.A. Orban, R. Vandenberghe, P. DuPont, B. De Bruyn, G. Bormans and I,. Mortelmans (Laboratorium voor Neuro- en Psychofysiologie, Campus Gasthuisberg and PET Center Nuclear Medicine, UZ Gasthuisberg, Louvain) Regional cerebral blood flow was compared in 6 conditions in which subjects either detected a grating or identified its orientation. In all conditions the subject fixated a spot 3” to the right. The stimulus was either a 2” grating presented centrally in the visual field, a 4” grating presented 5’ laterally into the left hemitield, or both stimuli but the subjects had to neglect the peripheral one. Comparison of the different conditions revealed several types of activation foci: (I) left or bilateral occipital foci representing the central visual field; (2) right occipital foci representing the peripheral visual field; and (3) parietal and parieto-occipital foci on both sides. The focus in R BA7 was activated only in discrimination peripherally suggesting that R SPL is most active when the subject is working visually with a peripheral stimulus, much more than when just detecting it. The R par-occ focus had a similar but less pronounced profile. The two foci in left BA 7 were active one in peripheral discrimination and in discrimination while neglecting the peripheral stimulus, the other in all 3 discrimination conditions. The former focus might relate to the effort to maintain eyes deviated despite the presence of an ipsilateral stimulus and the latter to the selection of movement process. 8. Contingent negative variation (CNV) in mood disorders. Papart, M. Ansseau and M. Timsit-Berthier (Psychiatric CHU du Sart Tilman, Lii?ge)
- P. Unit,
The assessment of depressive patients is essentially based on clinical symptomatology, which exhibits considerable limitations. It is therefore of major interest to develop methods able to objectivate clinical outcome during depressive episodes and to predict the response to treatment. In depression, CNV studies have shown abnormalities in both amplitude (too low or too high) and duration. In our studies, we found that depressed patients with low CNV amplitude had higher scores on the retardation factor of the Hamilton Depression Scale. After recovery, patients with low CNV amplitude during the active phase of the illness presented a significant increase of CNV amplitude whereas patients with high CNV amplitude during illness exhibited the opposite change. Low CNV amplitude patients had a preferential response to noradrenergic antidepressants whereas high CNV amplitude patients were better improved with serotonergic antidepressants. Taken together, these results suggest that normalization of CNV amplitude represents a reliable index of positive outcome and that the abnormalities of CNV amplitude (low or high) can predict the response to selective antidepressants. Moreover, low CNV amplitude also appears to characterize depression with psychomotor retardation. measurements in psychopharmacology. 9. Electrophysiological Pivont (Clinique “La Rambe,” Brussels)
- V.
Electrophysiological measurements are more and more used in psychiatry to understand the pathophysiology of mental diseases and to study the effects of several psychotropic drugs on the central nervous system. The usefulness and validity of the contingent negative variation (CNV), the P300 and the quantified EEG (qEEG) have been widely substantiated in the literature. In the miscellaneousness of psychiatric disorders, the amplitude of the CNV and the P300 may help in the choice of medication and therapeutical monitoring.
This corpus of data suggests that EPs might be useful to study the mechanisms of attentional disorders, the only reservation being that some of the above findings reach statistical significance in group, but not in individual, studies.
4. Event-related France)
desynchronization.
-
J.D.
Guieu
(C.H.R.
Lille,
Title only.
5. Cognitive function and the P300 event-related potential in epileptic patients in normal conditions and before and after sleep deprivation. - P.E.H. Van Nunen and A.C. Declerck (Heeze, The Netherlands)
Disturbances in attention and alertness are common complaints in patients suffering from epilepsy and are hard to measure objectively. The P300 component of the event-related brain potential seems to be an objective measurement of these cognitive functions. In a pilot study we found that P300 latency was prolonged in patients with epileptic seizures compared to controls. In the next study 48 patients with complex partial epilepsy (CPE) were assigned to 4 groups: (I) without medication, (2) a monotberapy of carbamazepine (CBZ). (3) a polytherapy including CBZ, (4) a polytherapy without CBZ. P300 latency and amplitude were compared to a control group (N = 11). We found the largest prolongation of P300 latency and the smallest amplitude in the CPE group without medication. Only the CPE group with a polytherapy including CBZ had normal latencies and amplitudes. We concluded that the disorder in brain function that caused their seizures also caused the cognitive impairment as measured by the P300. To determine the effects of I night of total sleep deprivation as well as the value of a 2-3 h long sleep compensation we performed another experiment. Epileptic patients came to our clinic for I night of total sleep deprivation followed by a compensatory period in the morning. Patients had to perform in an auditory oddball paradigm prior to sleep deprivation, immediately prior to the morning sleep, and again after being awakened. Preliminary results (N = 17) showed no differences in P300 latencies and amplitudes. These results suggest that biological influences such as sleep deprivation, which is a very provocative situation, and a compensatory sleep period have no effect on latency and amplitude of the P300. Thus whenever latency of the P300 is prolonged or its amplitude decreased there must be a disorder in cognitive function.
6. Neuropsychology pital, Ghent)
of eye movements.
- L. Crevits (University
Hos-
Numerous cortical and subcortical areas are involved in the control of eye movements. Only the visually guided saccadic system will be considered in the present review. All these saccades are triggered through two cortical poles, the frontal eye field (FEF) and the posterior parietal cortex (PPC>. The PPC is mainly concerned with reflexive saccades. No required reflexive saccades are inhibited by the prefrontal cortex. The FEF is principally involved in intentional saccades. Memory guided saccades are controlled successively by the PPC (visuospatial integration), the prefrontal cortex (spatial memorization). the supplementary motor cortex (temporal memorization), and the FEF (triggering). The parietal pole, especially on the right, seems to be essential for disengagement of spatial selective attention, the prefrontal region for maintenance of visual attention. Saccades are permitted if visual attention is disengaged, they are inhibited if attention is maintained (fixation). Subcortical area such as the basal ganglia and the thalamus are important relays in the cortico-subcortical circuits of both the saccadic
and the attentional systems. Finally, the superior colliculus role in visuo-oculomotor coordination,
109P
plays a crucial
7. The role of parietal cortex in control of attention to a peripheral target used in discrimination: evidence from PET. - G.A. Orban, R. Vandenberghe, P. DuPont, B. De Bruyn, G. Bormans and I,. Mortelmans (Laboratorium voor Neuro- en Psychofysiologie, Campus Gasthuisberg and PET Center Nuclear Medicine, UZ Gasthuisberg, Louvain) Regional cerebral blood flow was compared in 6 conditions in which subjects either detected a grating or identified its orientation. In all conditions the subject fixated a spot 3” to the right. The stimulus was either a 2” grating presented centrally in the visual field, a 4” grating presented 5’ laterally into the left hemitield, or both stimuli but the subjects had to neglect the peripheral one. Comparison of the different conditions revealed several types of activation foci: (I) left or bilateral occipital foci representing the central visual field; (2) right occipital foci representing the peripheral visual field; and (3) parietal and parieto-occipital foci on both sides. The focus in R BA7 was activated only in discrimination peripherally suggesting that R SPL is most active when the subject is working visually with a peripheral stimulus, much more than when just detecting it. The R par-occ focus had a similar but less pronounced profile. The two foci in left BA 7 were active one in peripheral discrimination and in discrimination while neglecting the peripheral stimulus, the other in all 3 discrimination conditions. The former focus might relate to the effort to maintain eyes deviated despite the presence of an ipsilateral stimulus and the latter to the selection of movement process. 8. Contingent negative variation (CNV) in mood disorders. Papart, M. Ansseau and M. Timsit-Berthier (Psychiatric CHU du Sart Tilman, Lii?ge)
- P. Unit,
The assessment of depressive patients is essentially based on clinical symptomatology, which exhibits considerable limitations. It is therefore of major interest to develop methods able to objectivate clinical outcome during depressive episodes and to predict the response to treatment. In depression, CNV studies have shown abnormalities in both amplitude (too low or too high) and duration. In our studies, we found that depressed patients with low CNV amplitude had higher scores on the retardation factor of the Hamilton Depression Scale. After recovery, patients with low CNV amplitude during the active phase of the illness presented a significant increase of CNV amplitude whereas patients with high CNV amplitude during illness exhibited the opposite change. Low CNV amplitude patients had a preferential response to noradrenergic antidepressants whereas high CNV amplitude patients were better improved with serotonergic antidepressants. Taken together, these results suggest that normalization of CNV amplitude represents a reliable index of positive outcome and that the abnormalities of CNV amplitude (low or high) can predict the response to selective antidepressants. Moreover, low CNV amplitude also appears to characterize depression with psychomotor retardation. measurements in psychopharmacology. 9. Electrophysiological Pivont (Clinique “La Rambe,” Brussels)
- V.
Electrophysiological measurements are more and more used in psychiatry to understand the pathophysiology of mental diseases and to study the effects of several psychotropic drugs on the central nervous system. The usefulness and validity of the contingent negative variation (CNV), the P300 and the quantified EEG (qEEG) have been widely substantiated in the literature. In the miscellaneousness of psychiatric disorders, the amplitude of the CNV and the P300 may help in the choice of medication and therapeutical monitoring.