Auditory Event-Related Potentials in Fetal Alcohol Syndrome and Down's Syndrome Children

Abnormal or borderline electroencephalograms are commonly observed in cases of gross mental retardation. However, fewer studies have focused on the use of event-related responses to aid in the differential diagnosis of developmental cognitive disorders. Fetal alcohol syndrome (FAS) and Down syndrome represent the most common known causes of mental retardation in the Western world. Although Down syndrome is easily diagnosed with a chromosome assay, FAS can be more difficult to diagnose since the diagnostic features are more subjectively based. The present study is the first to characterize auditory event-related potentials (ERPs) in children with FAS and contrast them to subjects with Down syndrome and controls. A passive auditory "oddball-plus-noise" paradigm was utilized to elicit ERPs. Parietal P300 latencies in response to the noise-burst stimuli for the FAS children were significantly longer, as were the P300s from all cortical sites in Down syndrome subjects in response to the both the infrequent tone and noise-burst stimuli when compared with the controls. Frontal P300s in Down syndrome children were significantly larger in amplitude compared to the controls and FAS children in response to the infrequent tone. A discriminant function analysis also revealed that these children could be correctly classified as being either Down syndrome, FAS, or normal controls using measures of latency and amplitude of the P300. These data suggest that an evaluation of ERP characteristics may provide a better understanding of the differences between FAS and Down syndrome children, and prove to be an aid in the early identification of children with FAS. These results demonstrate neurophysiological differences between FAS and Down syndrome, and suggest that P300 amplitude and latency data collected from a passive ERP task may be helpful in the discrimination of developmental cognitive disorders.     

The effects of age on auditory event-related potentials.

The effects of age on event-related potentials (ERPs) elicited during a two-tone discrimination ("oddball") task were examined in 97 normal subjects aged from 17-80 years. Strong relationships were found between age and the latencies of the later ERP components N200 and P300. Furthermore the correlation between age and N200 latency at Pz was marginally higher than that of age and P300 latency. For the entire sample, the increase in P300 latency as a function of age was best described at Cz and Pz by linear regression equations. However, a segmented line model better described the P300/age relationship at Fz--the increase in P300 latency with age in subjects over 61 was five times that of subjects younger than 61 years. In this study the task required button-press identification of the targets--the significance of increased age and a delay in N200 latency is discussed with reference to the possibility of N200 latency indexing the speed of cognitive processing.     

事件相关电位与视觉诱发电位诊断帕金森病的价值

目的　探讨事件相关电位 (ERPs)和视觉诱发电位 (VEP)在帕金森病中 (PD)的诊断作用。方法　对 6 0例正常对照组和 5 8例无认知障碍的 PD患者组进行了 ERPs和 VEP检测。结果　 PD组 ERPs的 P30 0 波潜伏期较对照组的明显延长 (P<0 .0 5 ) ,波幅则较对照组明显降低 (P<0 .0 5 ) ;PD组 VEP的 P1 0 0 波潜伏期较对照组明显延长 (P<0 .0 5 ) ,而波幅则无显著性差异 (P>0 .0 5 )。结论　 ERPs的 P30 0 和 VEP对帕金森病的亚临床认知功能障碍及视觉传导通路功能的检测具有独特的诊断价值     

阻塞性睡眠呼吸暂停综合征事件相关电位和记忆功能的相关性

目的 探讨阻塞性睡眠呼吸暂停综合征(OSAS)患者的P300指标变异情况和记忆功能状况的关系.方法 对浙江大学医学院附属第一医院2008年7月至2009年12月睡眠呼吸障碍专科门诊就诊的患者,进行夜间至少7h多导睡眠监测,共纳入OSAS患者30例,其中男22例,女8例,平均年龄(42±6)岁;对照组为健康志愿者20名,其中男15名,女5名,平均年龄(40±6)岁,分别进行韦氏记忆量表评定和事件相关电位P300检查.采用t检验、卡方检验和Pearson等级相关法对各组数据进行检验及比较.结果 OSAS组的记忆商评分为(86±13)分,与对照组比较有显著降低(P＜0.01);OSAS组的P300检查显示Cz、Pz点的潜伏期分别为(410±80) ms和(409±80) ms,较对照组明显延长(P＜0.01);Cz、Pz点的潜伏期与记忆商评分呈显著负相关(r=-0.581,-0.583,均P＜0.01),与睡眠呼吸紊乱指数呈正相关,差异有统计学意义(r=0.653,0.64,均P＜0.01);与平均血氧及最低SaO2呈负相关,差异有统计学意义(r=-0.755,-0.745,均P＜0.01;r=-0.67,-0.656,均P＜0.01).结论 OSAS患者存在明显的记忆功能障碍,P300潜伏期的延长可作为评估OSAS记忆功能障碍的电生理学指标之一;慢性间歇低氧可能导致与记忆相关的脑功能区域发生损伤性变化.     

Utility of P300 auditory event related potential latency in detecting cognitive dysfunction in growth hormone (GH) deficient patients with Sheehan's syndrome and effects of GH replacement therapy

OBJECTIVE: Impaired cognitive function has been demonstrated in adults with growth hormone (GH) deficiency (GHD) by using different neuropsychological tests. Despite several studies, present knowledge about the impact of GHD and GH replacement therapy (GHRT) on cognitive function is limited. P300 event-related potential (ERP) application is a well-established neurophysiological approach in the assessment of cognitive functions including the updating of working memory content and the speed of stimulus evaluation. GHD is a well-known feature of Sheehan's syndrome and cognitive changes due to GHD and the effects of GHRT remain to be clarified. The present study was designed to investigate the effects of GHD and 6 months of GHRT on cognitive function in patients with Sheehan's syndrome by using P300 latency. DESIGN AND METHODS: The study comprised 14 patients with Sheehan's syndrome (mean age, 49.5+/-7.8 years) and 10 age-, education- and sex-matched healthy controls. With hormone replacement therapy, basal hormone levels other than GH were stable before enrollment and throughout the GHRT. The diagnosis of GH deficiency was established by insulin-tolerance test (ITT), and mean peak level of GH in response to insulin hypoglycemia was 0.77+/-0.35 mIU/l. Treatment with GH was started at a dose of 0.45 IU (0.15 mg)/day in month 1, was increased to 0.9 IU (0.30 mg)/day in month 2 and was maintained at 2 IU (0.66 mg)/day. Initially baseline auditory ERPs in patients and controls were recorded at frontal (Fz), central (Cz), and parietal (P3 and P4) electrode sites. In the patient group, ERPs were re-evaluated after 6 months of GH replacement therapy. During each session P300 amplitude and latency were measured. RESULTS: Mean serum insulin-like growth factor-I (IGF-I) concentration in the patient group before GHRT was 23+/-13 ng/ml. After 6 months of GH therapy mean IGF-I significantly increased to an acceptable level, 234+/-71 ng/ml (P<0.05). The mean latencies (at all electrode sites) of the patients before GHRT were found to be significantly prolonged when compared with those of normal controls (P<0.05). After 6 months of GHRT mean P300 latencies (at all electrode sites) were decreased significantly when compared with latencies before treatment (P<0.05). CONCLUSIONS: The present study, using P300 ERP latencies, therefore suggests an impairment of cognitive abilities due to severe GHD in patients with Sheehan's syndrome and an improvement of cognitive function after 6 months of physiological GHRT. Moreover, this was a novel application of P300 ERP latencies in cognitive function detection in patients with GHD. Further studies with different patient groups need to be done to assess the clinical use of this electrophysiological method in the diagnosis of cognitive dysfunction due to GHD.     

Auditory P300 event related potentials and serotonin reuptake inhibitor treatment in patients with fibromyalgia

BACKGROUND: The P300 components of auditory event related potentials (ERPs) are objective measures related to information and cognitive processing. OBJECTIVES: To assess P300 ERPs in female patients with fibromyalgia (FM) in comparison with healthy age matched controls. To investigate the relationship between P300 potentials and pain threshold levels of patients, and subsequent effect of sertraline treatment on P300 potentials. METHODS: P300 auditory ERPs were studied in 13 untreated female patients with FM and 10 healthy controls matched for age, sex, and education. Pain pressure thresholds and total myalgic scores (TMS) were assessed with an algometer. Patients were evaluated for clinical measures and P300 potentials (recorded from the vertex) at the first visit, and then in the fourth and eighth weeks of sertraline treatment. RESULTS: Patients with FM had significantly lower P300 amplitudes, but not significantly different P300 latencies, than controls at entry. P300 latencies in patients correlated negatively with TMS (r(s)=-0.79, p<0.01) and P300 amplitudes correlated significantly with TMS (r(s)=0.53, p<0.05). Anxiety and depression scores did not correlate significantly with P300 latencies or amplitudes at the study entry. P300 auditory ERPs had increased amplitudes that had reached nearly the same levels as those of the controls at the eighth week without any significant change in their latencies. CONCLUSION: The results show reduced P300 amplitudes in patients with FM. Further studies assessing the relationship between P300 ERPs and neuropsychiatric tests are required for better clarification of the clinical relevance of P300 potentials in FM.     

Evaluation of cognitive performance by using P300 auditory event related potentials (ERPs) in patients with growth hormone (GH) deficiency and acromegaly

ContextImpaired cognitive performance has been demonstrated in adults with GH deficiency and acromegaly by using different neuropsychological tests. P300 event related potential (ERP) application is a well established neurophysiological approach in the assessment of cognitive performance.ObjectivesEvaluation of cognitive performance by using P300 ERPs has not been reported in acromegaly, and the comparisons of the P300 ERPs between the patients with GH deficiency and GH excess have not been done yet. Therefore present study was designed to investigate the effects of GH deficiency and GH excess on cognitive performance by using P300 ERPs.Design and MethodsThe study comprised 19 patients with severe GH deficiency, 18 acromegalic patients and 16 age, education and sex matched healthy controls. Baseline auditory ERPs were obtained at Fz (frontal), Cz (central), Pz (parietal) and Oz (occipital) electrode sites in GH deficient group, GH excess group and control group.ResultsThere was a significant difference between mean serum IGF-I levels in the GH deficient and acromegalic patients (48 ± 38 ng/ml and 742 ± 272 ng/ml, respectively) (P = 0.01). The mean P300 latency of the patients with GH deficiency was significantly (P = 0.0001) prolonged when compared with that of normal controls and acromegalic patients at all electrode sites. The mean P300 amplitude of the patients with acromegaly was significantly (P = 0.005) lower when compared with that of normal controls and GH deficient patients at all electrode sites.ConclusionsUsing ERPs recordings, the present study indicates the prolongation of P300 latencies in patients with severe GH deficiency and reduction of P300 amplitudes in patients with acromegaly. This study provides the electrophysiological evidence for the presence of cognitive dysfunction in both GH deficiency and GH excess, and different components of the cognitive performance are impaired in these conditions.     

Event-related potentials in HIV-infected outpatients.

Event-related potentials (ERP) were determined in 138 human immunodeficiency virus (HIV)-infected outpatients and 92 healthy controls of a corresponding age. Of the HIV-infected patients, 31.8% showed an abnormal latency of the P3-component of ERPs (P3-ERP), exceeding the mean value + 2 SD of P3-ERP latencies from age-matched healthy subjects. From the untreated patients in stage Walter Reed (WR) = 6, 71.4% had abnormal P3-ERP latencies, whereas in WR = 2, only 19.6% of P3-ERPs were abnormal. Fourteen patients were observed over a period of 3-16 months. P3-ERP latencies were shortened in 7 patients under treatment with zidovudine. A marked increase in P3-ERP latencies was observed in 7 untreated HIV-infected patients. It is assumed that ERPs are a useful neurophysiological method to detect early cerebral dysfunction in HIV-infected patients.     

Event-related potentials in patients with multiple lacunar infarcts.

We studied event-related potentials (ERPs) occurring in response to attended and unattended stimuli in 31 patients with multiple lacunar infarcts. ERPs were recorded during the performance of visual discrimination tasks using three kinds of stimuli. Each component of P300 response to infrequent nontarget stimuli and P300 response to infrequent target stimuli was defined as non-target P3 or target P3. The non-target P3 latency in patients with multiple lacunar infarcts was significantly longer than in 15 age-equivalent normal subjects, while no significant differences could be found in target P3 latency between patients and normal subjects. From the controlled/automatic standpoint these results suggest that multiple lacunar infarcts are related to impairment of automatic processing reflected by non-target P3, although controlled processing reflected by target P3, is less impaired.     

老年糖尿病伴或不伴脑梗死患者P300诱发电位测定的临床意义

目的探讨老年糖尿病伴或不伴脑梗死患者听觉认知电位P300的变化特点及诊断价值.方法采用听觉Cond序列刺激的诱发电位方法对81例老年糖尿病患者(其中35例合并有多发性脑梗死)与30例健康老人进行测试.结果(1)糖尿病组与对照组健康老人比较,前者P300波潜伏期明显延长,P300波波幅显著降低.(2)糖尿病伴脑梗死组与不伴脑梗死组比较,前者P300波潜伏期明显延长,P300波波幅显著降低.(3)糖尿病组伴血管性痴呆亚组(VD)与多发性脑梗死亚组(MI)比较,前者P300波潜伏期更显著延长(P＜0.001),VD组P300潜伏期与简易智能化量表(MMSE)评分呈显著性负相关(P＜0.005).(4)糖尿病伴抑郁组与不伴抑郁组比较,前者P300波潜伏期明显延长,P300波波幅显著降低.结论老年糖尿病患者比正常健康组P300波潜伏期明显延长,P300波幅明显降低,老年糖尿病组中合并脑梗死时P300波改变更为显著.因此P300测试更利于血管性痴呆的早期诊断及疾病严重程度的观察.     

The executive interview as a screening test for executive dysfunction in patients with mild dementia

OBJECTIVES: To validate the Executive Interview (EXIT25) as a screening instrument for executive cognitive dysfunction in patients with mild dementia. DESIGN: Validation using group comparison and correlation studies. SETTING: The Copenhagen University Hospital Memory Clinic, a multidisciplinary outpatient clinic based in a neurological setting. PARTICIPANTS: Thirty-three patients with mild dementia (MMSE score > or =20) and 30 healthy controls. MEASUREMENTS: The EXIT25, a 25-item screening instrument for executive dysfunction, was administered to all participants. Global cognitive function was measured using the MMSE. Patients were evaluated using traditional neuropsychological tests for executive dysfunction (Wisconsin Card Sorting Test, Trail Making Part B, Stroop Test, verbal fluency, design fluency, and verbal abstraction). Changes in behavior and functional impairment in activities of daily living were assessed using the Frontal Behavioral Inventory (FBI) and the Disability Assessment for Dementia Scale. RESULTS: EXIT25 scores were significantly higher in patients than in the healthy controls; MMSE scores could not account for the differences. Thirteen of the 25 items separated the two groups. EXIT25 was found to correlate significantly with the Stroop Test, the verbal fluency tests, and the FBI. CONCLUSION: The EXIT25 is able to capture executive cognitive deficits not primarily related to the general level of intellectual reduction in patients with mild dementia. In clinical practice, the EXIT25 might be a valuable supplement to the MMSE.     

遗忘型轻度认知损害患者工作记忆事件相关电位研究

目的研究遗忘型轻度认知损伤患者的工作记忆损害机制及敏感指标。方法将2004年10月至2005年12月解放军总医院门诊和住院15例遗忘型轻度认知损害患者和15名年龄、性别、受教育年限匹配的正常老年对照参与本研究。事件相关电位检查采用视觉刺激模式,成对的简单平面图形先后呈现,受试者比较刺激对是否相同,同时记录32导脑电、正确反应率及反应时间。结果患者组与正常老年组操作行为差异无显著性。刺激相同即匹配状态下两组P300波形分布均以顶部为著,事件相关电位P300潜伏期及波幅差异无显著性(F1,28=1.0324,P=0.3183;F2,42=0.543,P=0.585)。刺激相异即冲突状态下事件相关电位N270主要分布在前头部,患者组N270潜伏期较正常老年组明显延长(F1,28=25.3264,P=0.000),波幅差异无显著性(F1,28=0.507,P=0.482)。脑电地形图与上述结果相一致。结论遗忘型轻度认知损害患者前额ERP成分N270的变化可能反映了其工作记忆中央执行系统损害。N270在检测这一损害时较P300敏感。     

Parasympathetic dysfunction in rheumatoid arthritis patients with ocular dryness.

OBJECTIVE: To determine whether abnormalities in the function of the autonomic nervous system are associated with oral and ocular dryness in rheumatoid arthritis. METHODS: Pupillography was done using an infrared light reflection method (IRIS) to measure both parasympathetic function (constriction latency and the latency of maximum constriction velocity (MCV)) and sympathetic function (dilatation latency) in rheumatoid arthritis patients with and without ocular dryness. The Schirmer and Saxon tests were used to measure the tear and saliva production respectively. RESULTS: The Schirmer and Saxon test results in rheumatoid arthritis patients with ocular dryness were reduced (P < 0.05) compared with rheumatoid arthritis patients without ocular dryness and healthy controls. Constriction latency and MCV latency were prolonged in rheumatoid arthritis patients with ocular dryness compared to the other two groups (P < 0.05). A negative correlation was found between the degree of ocular dryness and both constriction latency and MCV latency. No correlation was found between the results of pupillography and saliva production. CONCLUSIONS: Parasympathetic dysfunction may play a role in ocular dryness in patients with rheumatoid arthritis.     

Neurophysiological evidence of cognitive impairment in patients without hepatic encephalopathy after transjugular intrahepatic portosystemic shunts

OBJECTIVES: We aimed to test the hypothesis that subclinical cognitive brain dysfunction in cirrhotic patients would deteriorate after a transjugular intrahepatic portosystemic shunt (TIPS) in the absence of clinically detectable hepatic encephalopathy. METHODS: Out of 49 consecutive cirrhotic patients receiving elective TIPS for recurrent variceal hemorrhage, we identified 22 patients who were not encephalopathic and had not undergone liver transplantation at 6-month follow-up and confirmed TIPS patency by Doppler ultrasound. Patients were tested before and 6 months after TIPS implantation using event-related (P300) cognitive evoked potentials, late somatosensory median nerve (N70) potentials, and standard psychometric tests (Mini-Mental State and trailmaking test A). Twenty-two age-matched healthy subjects served as controls. RESULTS: Relative to controls, patients showed significantly impaired P300 and N70 latencies and abnormal psychometric test results at baseline. Six months after the TIPS, a further impairment of P300 latency was observed (p = 0.005), whereas no relevant changes in N70 latency and psychometric test results occurred. CONCLUSIONS: In cirrhotic patients with portal hypertension, neurophysiological signs of cognitive brain dysfunction are detectable in the absence of hepatic encephalopathy. A further subclinical deterioration of cognitive processing was observed 6 months after the TIPS. These findings demonstrate an aggravation of subclinical hepatic encephalopathy after a TIPS.     

Cognitive function in non-demented older adults with hypothyroidism.

PURPOSE: (1) to evaluate objectively changes in cognitive function and electrophysiologic characteristics associated with hypothyroidism of varying severity and duration in primarily older persons; (2) to determine whether these changes are reversible when a euthyroid state has been attained after treatment with thyroid hormone. SUBJECTS AND METHODS: We enrolled 54 non-demented hypothyroid patients (31-99, mean 68.6 +/- 16.4 years) with biochemical evidence of hypothyroidism (38 had overt and 14 had minimal hypothyroidism) and 30 euthyroid controls (31-96, mean 63.7 +/- 18.4 years) screened for good general health. We evaluated attention, orientation, memory, learning, visual-spatial abilities, calculation, language, visual scanning, and motor speed using standardized neuropsychological tests. Electrophysiological measures of neurocognitive function included the P300 latency component of the auditory Event-Related Potentials (ERP) and conduction speed from eye to cortex, the P100 latency component of the Patterned Visual-Evoked Potential (PVEP). All patients were studied when hypothyroid. A subset of patients with minimal initial test abnormalities were available to be retested when euthyroid, 5 and 9 months after onset of thyroid replacement therapy. RESULTS: Hypothyroid patients showed significantly lower scores on the Mini-Mental Status Test (MMS) and on five of 14 neuropsychological tests as compared to controls. The neuropsychological tests affected were copying a cube (visual-spatial function), the Inglis Paired Associates Learning Test-Low and Medium association items (memory and learning), Animal Naming (word fluency/production), and the Trail Making A test (attention, visual scanning and psychomotor function. Hypothyroidism also was associated with longer P100 latencies of PVEPs to 20' checks, but showed no significant differences in PVEP P100 latency to 50' checks, nor in the latency of the auditory ERP component P300. There was a statistically significant correlation between a laboratory index of the severity of hypothyroidism (serum T4) and the Inglis Medium Association items and Animal Naming. There was a statistically significant improvement after 5 months of treatment on three of the timed performance tests that previous studies have shown to be most sensitive to brain dysfunction. CONCLUSION: Hypothyroidism in non-demented older adults is associated with impairments in learning, word fluency, visual-spatial abilities, and some aspect of attention, visual scanning, and motor speed. The MMS by itself was sensitive in differentiating hypothyroid patients with cognitive deficits from controls, while electrophysiological measures did not generally differentiate the hypothyroid patients from normal controls. The MMS was not sensitive to treatment effects, but treatment was associated with significant improvements in three of the most sensitive measures of cognitive dysfunction.     

经颅多普勒和P300检测评价老年糖尿病患者并发脑血管病变和认知功能的意义

目的　探讨老年糖尿病患者并发脑血管病变和认知功能的意义。方法　对 80例老年糖尿病患者及 6 0例年龄和性别相匹配的健康老年志愿者进行经颅多普勒 (TCD)和P30 0测试。结果　糖尿病患者颈内动脉颅外段血流速度明显高于对照组 (P <0 .0 1)。糖尿病并腔隙性脑梗死患者的动脉搏动指数明显高于无脑梗死组和对照组 (P<0 .0 1)。搏动指数与病程密切相关 (r =0 .4 9)。糖尿病并腔隙性脑梗死组与无脑梗死组和对照组比较 ,P30 0潜伏期显著延长 ,波幅降低 (P <0 .0 1)。糖尿病组P30 0潜伏期和波幅与糖尿病病程长短和有无高血压无明显相关性。结论　采用TCD、P30 0检测评价老年糖尿病患者的脑血管病变和大脑认知功能对临床有一定意义。     

The impact of age-related changes in event-related P300 potentials on detecting early cognitive dysfunction

Event-related P300 potentials that closely reflect cognitive brain functions show significant age-related latency prolongations. This aging-P300 interaction can best be approximated by third-order polynomial regressions. To delineate the clinical impact this special kind of regression function may have on detecting early cognitive dysfunction, we applied visual P300 potential data of healthy subjects (n = 344; age range, 18-98 years) to nondemented patients with either (i) chronic liver disease (n = 104; age range, 19-74 years) or (ii) cerebral arteriosclerosis (n = 80; age range, 38-80 years). As compared with linear regressions, third-order polynomial regressions for the age-related changes in P300 potential latencies showed a smaller latency increase during middle age, with an accelerating latency prolongation from age 60 onward. In patients with liver cirrhosis, third-order polynomial regressions yielded a rate of abnormal P300 potential latencies exceeding that of linear regressions absolutely by 17-21%, and relatively by 67-71%. Although the rate of P300 abnormalities was much lower in the CAD patients with either regression model, the relative increase in P300 abnormalities due to third-order polynomial regressions was 40-112.5%. In conclusion, normal data for the latencies of P300 potentials based on third-order polynomial regressions result in a higher sensitivity of P300 potentials for detecting early cognitive dysfunction. This gain in diagnostically important information is not offset by a loss in specificity, and may depend on the kind as well as stage of the disease, the age distribution of the patients and the degree of the P300 potential abnormalities.     

Visual Event-Related Potentials in Cirrhotic Patients without Overt Encephalopathy

Ambulant patients with cirrhosis and no clinical evidence of encephalopathy were screened for impaired brain function by neuroelectrophysiological testing dependent on cognitive function. Infrequent large checkerboard visual stimuli were randomly interleaved with frequent small ones to elicit P300 event-related potentials (ERPs). Three ERP components, N200, P3a and P3b, were derived from the electroencephalogram (EEG) by computer averaging. The use of 10% contrast and a minimum of four precisely placed scalp electrodes were found to be necessary for optimal separation of ERPs from sensory evoked potentials. Visual ERPs, onset/offset and pattern-reversal visual evoked potentials (VEPs), the spontaneous EEG and the time taken to complete a standard number connection test (NCT) were obtained from 20 normal adult subjects and 19 age-matched patients with histologically-confirmed cirrhosis and no clinical evidence of encephalopathy. The latencies and amplitudes of evoked potentials and the alpha rhythm of the EEG were determined. In 6 of the 19 patients the latencies of P3a and/or P3b exceeded the corresponding mean for controls+2 standard deviations of that mean. In 4 other patients the NCT was prolonged. In all of the patients the N200, VEPs and alpha rhythm of the EEG were normal. In conclusion: (i) Optimal isolation of ERPs is critically dependent on stimulus contrast and electrode placement; (ii) ERPs appear to be more sensitive than primary sensory evoked potentials or the EEG in detecting impaired brain neuroelectrophysiological function; and (iii) Cirrhotic patients without overt encephalopathy in whom P3a and/or P3b latencies are prolonged may have subclinical hepatic encephalopathy.     

Executive function and memory in relation to olfactory deficits in alcohol-dependent patients

BACKGROUND: Prior research indicates that chronic alcoholism is accompanied by olfactory deficits. These have been suggested to reflect dysfunctions in olfactory brain regions. The present study investigated the role of neurocognitive functioning in tests (executive function and memory) sensitive to the functional integrity of brain areas that are crucial to olfactory processing in patients with alcohol dependence. METHODS: Performance on olfactory functions (detection threshold, quality discrimination, identification), executive function (Wisconsin Card Sorting Test), and memory (German version of the California Verbal Learning Test) was assessed in 32 alcohol-dependent patients and 30 healthy comparison subjects, comparable in age, gender, and smoking status. RESULTS: Compared with controls, alcohol-dependent patients were impaired in all 3 domains, olfactory functions, executive function, and memory. In patients, olfactory discrimination ability was positively correlated with executive function performance. Regression analyses conducted to clarify the relation between group (patients vs controls), executive function, memory, and olfactory functions indicated that group was the only significant predictor of olfactory detection threshold and identification, and both group and executive function were found to be the significant predictors of olfactory discrimination. CONCLUSIONS: Olfactory deficits in alcohol dependence appear to be associated with prefrontal cognitive dysfunction. Results indicate that olfactory quality discrimination deficits are related to executive function impairment. These findings add to the available research on frontal lobe dysfunction in alcoholism, suggesting that alcohol-related olfactory discrimination deficits may be associated with impairment in the functional integrity of the prefrontal lobe.     

Event-related brain potentials in male hypogonadism.

Several studies based on psychometric tests have determined an impairment of cognitive functions in patients with androgen deficiency. However, little is known about event-related potentials (ERPs) alterations in male hypogonadism. We investigated alterations of ERP in male hypogonadism before and 3 months after gonadotropin treatment. ERPs were elicited in 20 untreated male patients with idiopathic hypogonadotropic hypogonadism (IHH) (mean age: 21.1+/-1.4 years) and in a group of 30 male controls with comparable mean age and educational level. ERP recordings were repeated 3 months after hCG/hMG treatment. Untreated hypogonadal patients had longer mean P300 latencies and increased P300 amplitudes when compared to those in controls (321.6+/-18.5 vs 299.3+/-20.1 msec, p=0.0002; 12.15+/-4.47 vs 9.38+/-3.02 microV, p=0.011, respectively). The mean P300 latencies did not change significantly 3 months after gonadotropin treatment, while P300 amplitudes were decreased significantly. P300 latencies did not correlate with serum testosterone and other hormone levels. We conclude that prolongation of P300 latencies and increased P300 amplitudes are associated with male hypogonadism, but P300 prolongation is not reversed 3 months after gonadotropin treatment. These findings confirm the occurrence of cognitive defects in hypogonadal patients and would support the hypothesis that perinatal androgen deficiency contributes to an insufficient cognitive development.