Background:Power in the gamma band EEG increases during saccades in normal subjects.Objective:To develop a potential method to quantify signs of cortical responsiveness in persistent vegetative state(PVS)we quantified...Background:Power in the gamma band EEG increases during saccades in normal subjects.Objective:To develop a potential method to quantify signs of cortical responsiveness in persistent vegetative state(PVS)we quantified gamma range EEG in association with conjugate slow ballistic eye movements(SBEM).Methods:The EEG and the simultaneous electro-oculogram were recorded in 14(8F/6M)PVS patients.Clinical scoring was based on the Glasgow Coma Scale(GCS)and Coma Rating Scale(CRS).The Wavelet Transform,followed by Hilbert transform was applied to the EEG and gamma power distribution was quantified relative to the timing of an eye movement.We correlated the clinical and the neurophysiological measures.Results:Gamma activity was present in all PVS patients.Its power was modulated in association with eye movements only in less severely affected patients,with minimum power prior to,and maximum power during the eye movement.In severely affected patients there was no evidence of a temporal relationship between gamma power and the phase of the eye movement.Conclusions:Detecting changes in the time course of gamma power in relation to conjugate ballistic eye movements provides a quantitative neurophysiological method for prospective longitudinal studies to explore if the preservation of this CNS function relates to the potential for recovery in PVS patients.展开更多
Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or ‘saccadic‘ocular pursuit has been reported in patients with cirrhosis, but no formal assess...Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or ‘saccadic‘ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with ci rrhosis and varying degrees of hepatic encephalopathy. The patient population co mprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years , with biopsy-proven cirrhosis, classified, using clinical, electroencephalogra phic, and psychometric variables, as either neuropsychiatrically unimpaired or a s having minimal or overt hepatic encephalopathy; patients were further categori zed in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. S PEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients wi th minimal hepatic encephalopathy, and more pronounced disruption, if not comple te loss, of smooth pursuit in patients with overt hepatic encephalopathy. The di fferences observed in quantifiable SPE Mindices between the healthy volunteers/u nimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In con clusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnor malities are likely to play a role. Treatment status confounds the classificatio n of neuropsychiatric status and should be taken into account when categorizing these patients.展开更多
文摘Background:Power in the gamma band EEG increases during saccades in normal subjects.Objective:To develop a potential method to quantify signs of cortical responsiveness in persistent vegetative state(PVS)we quantified gamma range EEG in association with conjugate slow ballistic eye movements(SBEM).Methods:The EEG and the simultaneous electro-oculogram were recorded in 14(8F/6M)PVS patients.Clinical scoring was based on the Glasgow Coma Scale(GCS)and Coma Rating Scale(CRS).The Wavelet Transform,followed by Hilbert transform was applied to the EEG and gamma power distribution was quantified relative to the timing of an eye movement.We correlated the clinical and the neurophysiological measures.Results:Gamma activity was present in all PVS patients.Its power was modulated in association with eye movements only in less severely affected patients,with minimum power prior to,and maximum power during the eye movement.In severely affected patients there was no evidence of a temporal relationship between gamma power and the phase of the eye movement.Conclusions:Detecting changes in the time course of gamma power in relation to conjugate ballistic eye movements provides a quantitative neurophysiological method for prospective longitudinal studies to explore if the preservation of this CNS function relates to the potential for recovery in PVS patients.
文摘Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or ‘saccadic‘ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with ci rrhosis and varying degrees of hepatic encephalopathy. The patient population co mprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years , with biopsy-proven cirrhosis, classified, using clinical, electroencephalogra phic, and psychometric variables, as either neuropsychiatrically unimpaired or a s having minimal or overt hepatic encephalopathy; patients were further categori zed in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. S PEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients wi th minimal hepatic encephalopathy, and more pronounced disruption, if not comple te loss, of smooth pursuit in patients with overt hepatic encephalopathy. The di fferences observed in quantifiable SPE Mindices between the healthy volunteers/u nimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In con clusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnor malities are likely to play a role. Treatment status confounds the classificatio n of neuropsychiatric status and should be taken into account when categorizing these patients.
