Auditory event-related potentials (ERPs) in healthy subjects and patients with dementia

To study the effects of aging and gender differences of ERP components, auditory ERPs were recorded in 106 healthy subjects. Forty-three patients with dementia of the Alzheimer type and 24 patients with vascular dementia were also studied. In healthy subjects, there was a significant positive linear correlation between P300 latency and age, with P300 latency increasing at the rate of 1.5 msec/year. Neither N100 nor P200 component was correlated with age. The amplitudes of N100, P200 and P300 components in females were slightly larger than those in males, but the differences were not significant. Not only P300 latencies but also P200 latencies were significantly different in healthy subjects, patients with dementia of the Alzheimer type and those with vascular dementia. In 74.4% of patients with dementia of the Alzheimer type and 62.5% of those with vascular dementia, the P300 latency was over 2 SE above the age-estimated regression line. The difference of the P300 latency prolongation may have resulted from the severity of dementia but not from the etiology of dementia.     

痉挛性斜颈体感诱发电位的研究

目的：探讨痉挛性斜颈患者大脑皮层功能的变化。方法：对30例痉挛性斜颈患者刺激正中神经后体感诱发电位（SEP）的P22、N30波潜伏期及P22、N30波幅进行比较分析,30例正常对照组仅在颈部主动向右侧扭转时对双侧P22、N30波幅进行比较分析。结果：病例组SEPP22、N30潜伏期正常,双侧比较差异无统计学意义,头部扭转方向的对侧大脑半球前中央区的P22-N30波幅比明显高于对侧,差异有统计学意义。正常对照组前中央区记录的双侧P22N30波幅比较差异无统计学意义。结论：SEP P22、N30潜伏期正常提示传导通路结构完整,头部扭转方向的对侧大脑半球前中央区的P22-N30波幅比明显高于对侧,提示患者对侧大脑皮层前中央区电活动存在异常的兴奋及抑制,即抑制性减弱,兴奋性增高,N30记录的是刺激正中神经SEP中长潜伏成分,可能来源于运动辅助区,进一步提示患者存在感觉一运动整合功能异常。     

Auditory event-related potentials in 50 melancholic patients: increased N100, N200 and P300 latencies and diminished P300 amplitude

BACKGROUND: To investigate whether there are some differences in Event-Related Potentials (ERP) between melancholic patients and healthy controls. To establish whether there is a relationship between abnormalities of ERP and severity of depression and psychomotor retardation. METHOD: Melancholic depressed patients (N=50) and normal comparison subjects (N=31) were assessed for latencies and interlatencies of N100, N200, N400, latency and amplitude of P300. The ERPs were studied with an 'oddball paradigm' in the auditory modality. Severity of depression was measured by the Hamilton Depression Rating Scale (HDRS) and psychomotor retardation with the Depressive Retardation Rating Scale (DRRS). RESULTS: The melancholic group showed a significantly higher latency in N100 (P<0.001), N200 (P<0.001) and P300 (P<0.001) and a significantly lower P300 amplitude (P<0.001) than healthy controls. No other differences were found either in the latencies of the N400 or in their interlatencies. HDRS and DRRS do not have any significant correlations with amplitude or latency measures. LIMITATIONS: The subjects of this study are inpatients, with a severe subcategory of depression and high average age. It is difficult to generalize these findings. CONCLUSIONS: The principal finding of this study is the increase in three of the four latencies measured (N100, N200 and P300) and in the decreased P300 amplitude in melancholic patients compared to normal controls. There is no association between these abnormalities and clinical variables.     

Male and female mice differ for baseline and nicotine-induced event related potentials

The usage patterns and biological effects of cigarette smoking differ significantly among men and women. This study seeks to clarify the interaction that exists between nicotine and biological gender by investigating changes in brain electrical activity after acute nicotine treatment. The P20, N40, and P80 components of the auditory evoked potential were examined in male and female C57BL/6J mice using a paired-stimulus gating paradigm. Consistent with previously published data, acute nicotine resulted in increased gating of the P20 but a decrease in that of N40. Nicotine also resulted in a lengthening of P20 latency but a decrease in that of N40 and P80. The P80 latencies of male and female subjects were differentially affected by nicotine, as males appeared to be more sensitive to its shortening effect. Males and females also exhibited differences in N40 and P80 amplitudes, both of which were smaller in males. The effects of gender on auditory evoked potential amplitude suggest dimorphic signaling in the N40 and P80 generators. Whether this electrophysiological sexual dimorphism has functional consequences for sensory or cognitive abilities requires additional research. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Event-related potential in patients with diabetes mellitus]

The event-related potential (ERP) was recorded for 24 patients with diabetes mellitus (age 67.5 +/- 8.5 years, mean +/- SD) and 28 healthy controls (age 61.0 +/- 10.6 years) to elucidate the involvement of the central nervous system (CNS) in diabetes mellitus. ERP was recorded during auditory discriminative tasks. The latencies of N100, P200, N200 and P300 from the Pz region were measured. Patients with diabetes mellitus showed significant prolongation of N200 and P300 latencies compared with the normal subjects, while no significant differences in N100 and P200 latencies were found between the two groups. In six of 24 patients, the P300 latency delayed beyond the 2SD of the appropriate age-related value estimated from the normal regression line. The delay of the P300 latency was not related to either the duration of illness, therapeutic methods, or metabolic control. From the present results, it would appear that higher brain function is impaired even in diabetic patients not manifesting overt CNS signs and symptoms.     

Auditory evoked potentials as possible predictors of outcome in schizophrenic outpatients

As part of a follow-up study on long-term neuroleptic treatment, 36 schizophrenic out-patients under neuroleptic treatment were studied in an 'auditory oddball' event-related potential paradigm after a 3-month stabilization phase following clinical discharge. In the first cross-sectional analysis, we evaluated the influences of age and gender and tried to find auditory evoked potential (AEP) variables, which might be promising as potential predictors of the course of illness. Compared with healthy age-matched controls, the patients showed smaller N1/P3-amplitudes. Males and females showed only minor AEP-differences, the amplitude N1/P2 being slightly higher in females. Age correlated positively with the latency P3 and negatively with the latency P2R. The interpeak latency P3-P2R showed the highest correlation with age. Test/re-test reliability was measured and variables with r less than 0.60 were rejected. The amplitudes N1/P2 and N1/P3 showed the highest test/re-test correlations. The more severely disturbed patients (global assessment scale [GAS]-score less than 65) had shorter interpeak latencies P2F-N1F than the less disturbed patients (GAS greater than or equal to 65). Patients with a high rate of relapse tended to have shorter interpeak latencies P2F-N1F than patients with low rates of relapse. Our results indicate that the interpeak latency P2F-N1F has an acceptable test/re-test reliability (C3: r = 0.72; C4: r = 0.80) and is related to clinical variables characterizing the course and outcome of illness. This leads to the hypothesis that a short interpeak latency, P2F-N1F, might be a predictor of poor prognosis.     

P300 latency and amplitude in the diagnosis of dementia

P300 latency and amplitude were investigated in 10 normal elderly individuals, 10 institutionalized elderly persons with dementia not of the Alzheimer's types, and 10 elderly people with Alzheimer's disease. Significant differences between control and dementia groups (but not between dementia groups) were noted in the P300 latency, but not amplitude. Such differential latencies were observed in the anterior and in the left temporal and parietal areas of the brain.     

Amplitude reduction in visual event-related potentials as a function of sleep deprivation

Eight adult males were subjected to 40 hours of total sleep deprivation (TSD). Reaction time in a visual task and electroncephalographam (C3) were evaluated every 2 hours. One second of EEG before the stimuli was Fourier-transformed, and 750 ms after target and nontarget stimuli were averaged and visual event-related potentials (ERP) were obtained. Factorial analysis identified time windows that showed significant amplitude reduction and longer latencies with TSD: (1) 140 to 288 ms (P180-N242-P281); (2) 288 to 413 ms and 601 to 749 ms (N382; P718) and; (3) 531 to 601 ms (N500). Effect was strongest for N382 and P718, the amplitudes of which dropped to 20% of original size. The entire waveform recovered initial amplitudes and latencies after recovery sleep except for P718 latency. Waveforms within similar time intervals have been associated with attentional gating, sensory discrimination, target selection, uncertainty and decision processes. Amplitudes of the visual ERP were inversely correlated with hours of TSD, reaction time, and absolute power of the prestimulus EEG. Present results clearly show changes in fundamental neurophysiologic mechanisms as a result of TSD, indicating variability and reduction of the alertness mechanisms and changes in thalamocortical gating affecting attention, discrimination and decision-making.     

Gender differences in the recognition of spatially transformed figures: Behavioral data and event-related potentials (ERPs)

The gender differences in accuracy, reaction time (RT) and amplitude of the early P1 and N1 components of ERPs during recognition of previously memorized objects after their spatial transformation were examined. We used three levels of the spatial transformation: a displacement of object details in radial direction, and a displacement in combination with rotation of the details by ±0° to 45° and ±45° to 90°. The accuracy and the RT data showed a similarity of task performance in males and females. The effect of rotation was significantly greater than the effect of simple displacement, and the accuracy decreased, and the RT increased with the rotation angle in both genders. At the same time we found significant sex differences in the early stage of visual processing. In males the P1 peak amplitude at the P3/P4 sites increased significantly during the recognition of spatially transformed objects, and the wider the angle of rotation the greater the P1 peak amplitude. In contrast, in females the P1 peak amplitude did not depend on the rotation of figure details. The N1 amplitude revealed no gender differences, although the object transformation evoked somewhat greater changes in the N1 at the O1/O2 sites in females compared to males. This new fact that only males demonstrated the sensitivity of early perceptual stage to the transformation of objects adds information about the neurobiological basis of different strategies in the visual processing used by each gender.     

An examination of evoked K-complex amplitude and frequency of occurrence in the elderly

The elderly consistently display lower levels of slow wave sleep (SWS), primarily because of the small amplitude of their delta activity. Given that delta electroencephalogram (EEG) and K-complexes are thought to be generated by the same mechanisms, it was hypothesized that K-complex amplitude and rate of production would be lower in the elderly. K-complex amplitude was assessed by averaging K-complex responses to auditory stimuli, and measuring the amplitude of the N550 component of the averaged evoked response. Ten young (five males and five females; mean age 23.10 +/- 5.36 years) and 10 elderly adults (six males and four females; mean age=75.60 +/- 4.48 years) who were neurologically healthy and free from medication spent two non-consecutive nights in the sleep laboratory. EEG was recorded from six gold plate electrodes (Fz, Fcz, Cz, Cpz, Pz and O2) referenced to A1 + A2. Tone clicks (1000 Hz), of varying intensity from 70 to 100 decibels above measured awake detection threshold, were presented binaurally during stage 2 sleep. Responses were classified according to whether they produced: a K-complex, a vertex sharp wave (VSW), both of these responses or neither response. They were then averaged separately for each response type. The elderly showed a substantially smaller N350 (averaged VSWs) and N550 amplitudes compared with the young subjects. The elderly also showed an augmented but delayed P2 component, followed by a long-lasting positive EEG shift. The smaller amplitude of the averaged K-complex N550 component is consistent with lower delta amplitudes previously reported in the elderly and with the hypothesis that K-complexes and delta activity share the same generator mechanisms. The enhanced P2 component and the long-lasting positive deflection in the EEG in the elderly indicate the existence of age differences other than smaller EEG amplitude.     

性别因素对老年期神经系统变性过程的影响

目的：研究探讨正常人进入老年期后，性别和年龄对事件相关电位的交互作用影响是否仍然持续。方法：应用神经心理学测试和MRI检查筛选日本冲绳县年龄在60岁以上的正常老年人40名。其中男性17名，平均年龄是72．2±8．6岁；女性23名，平均年龄是75．7±8．2岁。应用听觉“oddball”范式诱发事件相关电位P300。分析Fz和Pz部位记录到的事件相关电位内源性成分P300和N2b。结果：P300潜伏期、P300波幅和N2b潜伏期的组间差异不显著。于Fz部位，男性组的N2b波幅低于女性组（F=4．59，P=0．039）。P300潜伏期和P300波幅与年龄的相关性，仅见于男性组（Fz-P300潜伏期：r=0．584，P=0．014；Fz-P300波幅：r=-0．782，P〈0．001；Pz—P300潜伏期：r=0．587，P=0．013；Pz—P300波幅：r=-0．657，P=0．004）。P300潜伏期和P300波幅对年龄的线性回归坡度，在两组闾均有显著性差异，在男性组更为陡峭（Fz—P300潜伏期：t=2．11，P=0．042；Fz-P300波幅：t=2．55，P=0．015；Pz-P300潜伏期：t：2．70，P=0．011：Pz-P300波幅：t=3．00，P=0．005）。结论：性别因素对老年期神经系统变性过程有显著影响。     

Progression of visual evoked potential abnormalities in multiple sclerosis and optic neuritis

To investigate visual signal processing in patients with optic neuritis, suspected multiple sclerosis, confirmed multiple sclerosis (MS), and optic neuritis combined with MS, pattern reversal visual evoked potentials (VEPs) were recorded in patients and normal subjects. The amplitude and latency of the first positive peak, P100 were determined to assess electrical conduction in patients as compared to normal subjects. Suspected MS patients did not differ from normal subjects in peak latencies or amplitudes. The P100 amplitude was reduced in optic neuritis, confirmed MS and optic neuritis combined with confirmed MS. The P100 and N145 latencies were prolonged in optic neuritis patients and confirmed MS patients as compared to normal subjects. The main characteristic of optic neuritis was P100 amplitude reduction, and of confirmed MS was P100 latency delay. There was a progression of the P100 latency delay and of the P100 amplitude decrement in optic neuritis, confirmed MS, and optic neuritis combined with confirmed MS. These results indicate a progression of demyelination in optic neuritis, confirmed MS, and optic neuritis combined with confirmed MS.     

Median sep and blink reflex in thyroid diseases

Pathological disturbances of thyroid hormones is associated with central and peripheral nervous system disturbances. The aim of this study is to evaluate median nerve stimulated somatosensory evoked potential (SEP) and blink reflex of thyroid patients (hypo and hyperthyroidism). Median SEP was performed in 40 patients (21 with hyperthyroidism and 19 with hypothyroidism). We evaluated the latencies of N9, N11, N13, P9, P11, P14, N20 and P25 waves and the N9-N20, N9-N13, N13-N20 and P14-N20 interpeak latencies. We compared the results of patients with the control group (26 persons). We found that the N20 latency was longer in patients with hyperthyroidism than in the control group and the difference was statistically significant. There was not any statistically significant difference regarding the N9, N11, N13, P9, P11, P14, N20 and P25 latencies and the N9-N20, N9-N13, N13-N20 and P14-N20 interpeak latencies between hypothyroid patients and controls. We performed the blink reflex study in 28 of 40 patients (14 patients with hyperthyroidism and 14 patients with hypothyroidism). Comparing the R1, R2, CR2 (contralateral R2) latencies and durations of the patients and controls, we found that R2 and CR2 duration was shorter in patients with hyperthyroidism. This difference was statistically significant.     

Heritability of event-related brain potentials in families with a history of alcoholism.

Event-related brain potentials (ERPs) are altered in patients with a variety of psychiatric disorders and may represent quantitative correlates of disease liability that are more amenable to genetic analysis than disease status itself. Estimates of heritability are presented for amplitude and latency of the N1 and P3 components of the ERP measured at 19 scalp locations in response to visual and auditory stimuli for 604 individuals in 100 pedigrees ascertained as part of the Collaborative Study on the Genetics of Alcoholism. Significant heritabilities were found for visual P3 amplitude in response to all stimuli and for visual P3 latency in response to target and novel, but not non-target, stimuli. Heritability of visual N1 latencies was uniformly low, whereas heritability of visual N1 amplitude was significant for all electrodes in response to the non-target stimuli but only for posterior electrodes in the other two stimulus conditions. Heritabilities for auditory target P3 were similar to those of the visual stimuli, with auditory target P3 amplitudes and latencies both demonstrating significant heritability. For auditory P2 in response to non-target stimuli, peak amplitude was heritable, but latency was not. Auditory N1 amplitude and latency were significantly heritable for both target and non-target conditions and did not demonstrate the anterior/posterior patterning obtained for visual N1 amplitude. This study represents the first systematic assessment of heritability of these potential neurophysiological markers in families with a history of alcoholism and suggests that many of these ERP phenotypes have heritabilities strong enough to justify genomic screening for loci jointly influencing ERP abnormalities and liability to alcoholism.     

ApoE genotype and abnormal auditory cortical potentials in healthy older females

Apolipoprotein E (ApoE) status and gender are risk factors for the development of Alzheimer's disease. Alzheimer's disease is more prevalent in female relative to male carriers of the ApoE epsilon 4 gene. We examined cortical sensory (P50, N100) and cognitive (P300) potentials in an auditory target detection task in females as a function of ApoE genotype (ApoE epsilon 4 carriers, ApoE epsilon 4 non-carriers) to define the incidence of abnormalities prior to the clinical expression of cognitive impairments. Both neuropsychological test scores and sensory cortical potentials did not differ between the two ApoE groups. In contrast, cognitive P300 potentials were significantly decreased in amplitude and delayed in latency for ApoE epsilon 4 carriers compared to non-carriers. Four out of the 10 ApoE epsilon 4 carriers had abnormally (>2S.D.) delayed P300 latency compared to one out of 20 non-carriers. Abnormal cognitive processes reflected by P300 latency delays are expressed at significantly higher incidence in normal older females who are carriers of the epsilon 4 allele than in non-carriers of this allele.     

老年糖尿病人P300认知电位改变及相关因素分析

目的：了解老年糖尿病人P300认知电位的改变及与病程、糖代谢及并发症的关系。方法：采用听觉oddball序列刺激的诱发电位方法对50例老年糖尿病人及20例健康老年人进行测试。结果：糖尿病组与对照组比较,糖尿病并腔隙性脑梗塞组与无脑梗塞组比较P300波潜伏期显著延长,P300波波幅显著降低,糖尿病组P300波潜伏期和波幅与病程长短、糖化血红蛋白及有无高血压病无明显相关。结论：老年糖尿病人比正常老年人P300波潜伏期明显延长,P300波波幅明显降低,合并腔隙性梗塞可能是其P300波改变的主要原因之一。     

Heritability of event-related brain potentials in families with a history of alcoholism

Event-related brain potentials (ERPs) are altered in patients with a variety of psychiatric disorders and may represent quantitative correlates of disease liability that are more amenable to genetic analysis than disease status itself. Estimates of heritability are presented for amplitude and latency of the N1 and P3 components of the ERP measured at 19 scalp locations in response to visual and auditory stimuli for 604 individuals in 100 pedigrees ascertained as part of the Collaborative Study on the Genetics of Alcoholism. Significant heritabilities were found for visual P3 amplitude in response to all stimuli and for visual P3 latency in response to target and novel, but not non-target, stimuli. Heritability of visual N1 latencies was uniformly low, whereas heritability of visual N1 amplitude was significant for all electrodes in response to the non-target stimuli but only for posterior electrodes in the other two stimulus conditions. Heritabilities for auditory target P3 were similar to those of the visual stimuli, with auditory target P3 amplitudes and latencies both demonstrating significant heritability. For auditory P2 in response to non-target stimuli, peak amplitude was heritable, but latency was not. Auditory N1 amplitude and latency were significantly heritable for both target and non-target conditions and did not demonstrate the anterior/posterior patterning obtained for visual N1 amplitude. This study represents the first systematic assessment of heritability of these potential neurophysiological markers in families with a history of alcoholism and suggests that many of these ERP phenotypes have heritabilities strong enough to justify genomic screening for loci jointly influencing ERP abnormalities and liability to alcoholism. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:383–390, 1999. © 1999 Wiley-Liss, Inc.     

Ontogeny of maternal behavior in the laboratory rat: factors underlying changes in responsiveness from 30 to 90 days.

Male and female rats that were nonhandled or that were handled from weaning, and that had intact or impaired olfaction (intranasal zinc sulfate), were sensitized through continuous pup exposure commencing at 30, 45, 60, or 90 days of age. Nonhandled males and females were alike in latencies to become maternal at Day 30 but thereafter latencies of females became shorter and latencies of males lengthened; by 90 days males had markedly longer latencies than females and only 1/3 became maternal. Handling facilitated sensitization at 30 days among males and females but only among males at 45 and 60 days. Intranasal zinc sulfate reduced latencies of both males and females at all ages tested, but appeared most effective after 45 days of age. Gender differences in latencies persisted in adult animals even after combined treatments. Results indicate that both timidity and olfaction inhibit the onset of maternal responses to pups in virgin males and females, but they differ in relative importance by age and gender.