Bereitschaftspotential preceding eyelid blinks in Parkinson's disease / Potencial de Bereitschafts precedendo o piscamento ocular na doença de Parkinson

ABSTRACT The Bereitschaftspotential (BP) is a negative wave observed in EEG retrograde averaging, preceding a motor act. The objective was to study the BP preceding voluntary eyelid blinks in Parkinson's disease (PD) patients during off and on phases of levodopa. Methods Ten PD patients in stages 1 and 2 of the Hoehn & Yahr classification were compared to 18 healthy controls. Artifact-free EEG segments of two seconds preceding the onset of the blink potential were averaged and analyzed, and the statistical significance of the measured amplitudes were evaluated by analysis of variance models. Results The presence of a BP in the PD patients was demonstrated. The mean amplitudes at 0 ms were respectively 0.6 µV and 3.3 µV for the BP patients and the normal controls, respectively. Conclusions The BP amplitudes were significantly smaller in PD patients than normal participants. The amplitudes of the BP were not modified by levodopa.

RESUMO O Potencial de Bereitschafts (PB) é uma onda negativa observada retrogradamente no EEG precedendo um ato motor. Objetivo Estudar o PB precedendo o piscamento palpebral voluntário em pacientes com doença de Parkinson (DP) durante as fases off e on da levodopa. Foram comparados dez pacientes com DP nos estágios 1 e 2 de Hoehn & Yahr com 18 controles saudáveis. Os segmentos de EEG livres de artefatos 2 segundos antes do início do potencial foram calculados e analisados e a significância estatística das amplitudes foi medida por modelos de análise de variância. Resultados A presença de PB nos pacientes com DP foi demonstrada. As amplitudes médias a 0 ms foram respectivamente 0,6 μV e 3,3 μV para os pacientes com DP e controles respectivamente. Conclusões As amplitudes do PB foram significativamente menores nos pacientes com DP do que controles. As amplitudes do PB não foram modificadas pela levodopa.

Contingent Negative Variation Is Associated with Cognitive Dysfunction and Secondary Progressive Disease Course in Multiple Sclerosis

BACKGROUND AND PURPOSE: The relationship between contingent negative variation (CNV), which is an event-related potential, and cognition in multiple sclerosis (MS) has not been examined previously. The primary objective of the present study was thus to determine the association between CNV and cognition in a sample of MS patients. METHODS: The subjects of this study comprised 66 MS patients [50 with relapsing-remitting MS (RRMS) and 16 with secondary progressive MS (SPMS)] and 40 matched healthy volunteers. A neuropsychological battery was administered to all of the subjects; CNV recordings were made from the Cz, Fz, and Pz electrodes, and the amplitude and area under the curve (AUC) were measured at each electrode. RESULTS: RRMS patients exhibited CNVs with lower amplitudes and smaller AUCs than the controls at Pz. SPMS patients exhibited CNVs with lower amplitudes and smaller AUCs than the controls, and CNVs with a smaller amplitude than the RRMS patients at both Cz and Pz. After correcting for multiple comparisons, a lower CNV amplitude at Pz was significantly associated with worse performance on measures of speed of information processing, verbal fluency, verbal learning, and verbal recall. CONCLUSIONS: CNV may serve as a marker for disease progression and cognitive dysfunction in MS. Further studies with larger samples and wider electrode coverage are required to fully assess the value of CNV in these areas.

The study of sustain attention of CNV in patients with subcortical ischemic vascular cognitive impairment / 中国神经精神疾病杂志

Objective To investigate the characteristics of contingent negative variation(CNV) in patients with subcortical ischemic vascular cognitive impairment (SIVCI) and their relationship with continuous performance task (CPT) to establish a neuroelectrophysiological index of attention impairment in earlier period of Vascular Cognitive Impair-ment. Methods CNV was assessed in 45 SIVCI patients [30 patients with subcortical ischemic vascular cognitive impair-ment no dementia (SIVCIND ) and 15 patients with subcortical ischemic vascular dementia (SIVD )] and 15 normal con-trol (NC) by using a EB-Neuro ERP Instrument. Results ①CNV in SIVCI group were less regular compared with nor-mal control;CNV in SIVCIND group had decreased Expectancy Wave (EW) amplitudes (9.98± 4.10μV vs. 16.13±2.75μV) and EW areas (14848.10 ± 3199.16 μV · ms vs 20058.87 ± 1025.95 μV · ms) compared with normal control (P0.05);②Pearson correlation\Spearman rank correlation analysis revealed that there were significant, positive correlations between EW latency and CPT Reacting time(R=0.748, P0.05)、EW amplitude(R=-0.191,P>0.05)and there were significant, negative correlations between EW area and CPT Reacting time(R=-0.718,P<0.01)、CPT missing rate(R=-0.829 ,P<0.01), EW amplitude and CPT Reacting time(R=-0.616, P<0.01). Conclusion SIVCI patients in early stage have attention deficits in sustained attention and CNV EW ar-ea may be a good neuroelectrophysiological index for sustained attention impairment .

The Contingent Negative Variation in Remitted Paediatric Bipolar Patients: No Evidence of Abnormality

Although the Contingent Negative Variation (CNV) paradigm has been useful in schizophrenia, limited research involving such paradigm in subjects with Bipolar Disorder (BD) has produced contradictory findings. To the best of our knowledge, no study has investigated CNV in Paediatric Bipolar Disorder (PBD) subjects. Thirty remitted PBD patients and thirty matched healthy control group subjects participated in the study. No significant between group main effect could be found for either CNV latency or amplitude. We propose that CNV is unlikely to be a true endophenotype of BD. However, absence of CNV finding during euthymic phase in BD may help us in advancing our understanding of BD and such finding may, in fact, have some specificity with regard to differentiating BD from schizophrenia.

Meditation as an intervention for cognitive disturbances following total sleep deprivation.

Background & objectives: Decline in cognitive functions is a major challenge for professionals during sustained wakefulness. We used middle latency response (MLR), event related potentials P300-ERP and contingent negative variation (CNV) and Raven’s Advanced Progressive Matrices (RAPM) - a standard neuropsychological test were used to evaluate cognitive impairment after total sleep deprivation (SD); and to study the impact of meditation as an intervention for this impairment. Methods: Healthy male volunteers (n=10) drawn randomly from the Indian Army participated in a 6-night study design executed before and after two months of meditation practice: night 1–adaptation, night 2–baseline, night 3–24 h SD, night 4–recovery sleep, night 5–24 h SD after 60 days meditation, night 6–recovery sleep after SD. A 36 h SD was obtained by keeping the subject awake for 12 h after 24 h SD. Results: The latency and amplitude of P300 increased after 36 h SD. Amplitudes and latencies of both early and late CNV increased after 24 and 36 h SD, indicating deficient orientation and impairment of attention and perception. Prolonged CNV reaction time after 36 h SD manifested deficient motor response following second (imperative) stimulus. Latency of MLR Na registered significant change following 36 h SD compared to baseline (P<0.01) and recovery (P<0.05). RAPM score showed significant decrease after 36 h of wakefulness indicating impaired analytical ability and difficulty in problem solving. None of these parameters showed any significant alteration after SD, following meditation practice. Interpretation & conclusions: The present results showed that SD impaired cognitive performance to graded extents significantly, but this deterioration could be improved to a significant extent using meditation.

Effects of repeatedly forced swim stress on CNV-like potential in rats / 中华行为医学与脑科学杂志

Objective To explore whether there were abnormalities of behavioral tests and CNV-like potential in stressed rats following repeatedly forced swim stress.Methods Forty male rats were randomly divided into 4 groups: the control groups (Control-1 and Control-2) and the stress groups ( Stress-1 and Stress-2).Rats in stress groups were administered to repeatedly forced swim 7 or 14 days respectively.Body weight gain, saccharin preference test and open field test were performed.After being anesthetized with urethane, CNV-like potentials were elicited by condition-test stimulus.Results Results of behavioral tests displayed less body weights (F =253.60, P＜0.001 ) and less saccharine solution intake (F= 13.67, P=0.001 ) in stressed group rats and significant effects of stress on the number of crossing squares, the duration of rearing and the number of grooming in open field test.CNV amplitudes were lower in the stressed rats than those in control (F=21.312, P＜0.01 ).Conclusion This study provides an important evidence of changes of CNV-like potential in depressed rats following repeatedly forced swim stress.Based on this study, ER Ps should be taken into consideration and applied as the useful tools in the research work of depressed animal models.

Study on contingent negative variation in anxiety disorder / 上海第二医科大学学报

0.05)and significantly delayed reaction time,(305?109)ms vs(212?70)ms(P

Contingent Negative Variation of Pre- and Post-Hemodialysis in Patient with End Stage Renal Disease

BACKGROUND: The contingent negative variation (CNV) reflects neuronal activities related to sensorimotor integration and motor planning or execution and is probably originated from the frontal-subcortical circuit. The aim of this study is to investigate the neurophysiologic changes in uremia and the effect of hemodialysis to them by utilizing the CNV test. METHODS: Fifteen right-handed healthy subjects and 12 patients with end stage renal disease (ESRD) were studied. CNV was recorded from Fz, Cz, and Pz referenced to linked ear lobes by using an S1 (click)-S2 (flashes)-key press paradigm. The amplitude of initial CNV (iCNV) was calculated as the average amplitude of 550~750 msec after S1. The amplitude of late CNV (lCNV) was calculated as the average amplitude between 200 msec before S1 and S2. The test was repeated for the patients group at the time of pre- and post-hemodialysis. Neuropsychological measurements, the trail making test (TMT) and mini-mental state score (MMSE), were conducted at the time of each test. RESULTS: Both the mean amplitudes of iCNV and lCNV at the vertex (Cz) were significantly lower in the patient group than those in the control group (p<0.05). The MMSE score and TMT were also significantly different between the patient and control group (p<0.05). There was no significant correlation between the values of neuropsychological tests and the parameters of CNV. Both iCNV and lCNV were not significantly different between the pre- and post-dialysis test. CONCLUSIONS: It appears that CNV negativity in uremia reflects dysfunctions in the frontal-subcortical circuit. In addition, hemodialysis seems to have no significant effect on it in patients with ESRD.

Contingent negative variation in the aged with memory impairment and dementia tendency in the course of advance towards dementia / 中华老年医学杂志

Objective To investigate the feature and general trend of the contingent negative variation (CNV) in the aged with memory impairment (AMI) and dementia tendency in the course towards advanced dementia. Methods CNV in 69 AMI subjects (serving as the study group) and 22 healthy elderly subjects selected from well age matched (serving as the control group) were examined. Hasegawa's dementia scale for the aged (HDS) in all AMI were also examined. 2 3 years later, 22 from the study group were examined again. The wave forms and relevant indexes of CNV were observed and analyzed. Results Reaction time(RT)〔(284.3?170.6) ms vs (149.8?101.7) ms, P