Transient ischemic attacks: electrophysiological (conventional and topographic EEG) and radiological (CCT) evaluation

Spectral analysis of EEG in etiological assessment of patients with transient neurological deficits

OBJECTIVE

Differentiating transient ischemic attack from stroke mimics may be difficult. Besides clinical evaluation and brain imaging, electroencephalography (EEG) may be a useful diagnostic tool.

METHODS

We conducted spectral analysis on 67 EEG of patients who had presented a transient neurological deficit (TND) within the previous seven days. Expert clinicians provided the final diagnosis: transient ischemic attack, migraine with aura, focal seizure or "other". We first calculated the relative power of the four EEG frequency bands (delta, theta, alpha and beta), in the whole hemisphere, then, according to the clinical symptoms, in the relevant electrodes of the symptomatic hemisphere. Finally, we calculated the relative power ratio between symptomatic and asymptomatic hemispheres.

RESULTS

Median age was 60.6 years (57% females). The etiological diagnosis was transient ischemic attack (27%), migraine with aura (11%), focal seizures (22%) and "other" (40%). We did not find significant differences in the theta and delta relative power analysis between groups. Over the symptomatic hemisphere only, we found a significant increase of the alpha relative power (p = 0.0026, p < 0.0001, p = 0.0014) in the migraine group compared to transient ischemic attack, migraine and focal seizures groups, and a significant decrease of the beta relative power (p = 0.0034, p = 0.0016, p = 0.0005) compared to the same groups.

CONCLUSIONS

Migraine with aura presents a discriminative EEG relative power in comparison to transient neurological deficits of other origins. To further investigate the additive diagnosis value of EEG in other TND, future studies should be performed with an EEG obtained within the first 24 h after the onset of symptoms.

SIGNIFICANCE

Spectral EEG analysis discriminates migraine with aura groups from other groups, but not at the individual level.

Psychological and physiological effects of viewing a money plant by older adults

BACKGROUND

Observing plants can induce neurophysiological responses that can alleviate stress and reduce anxiety. However, few studies have examined such effects in older adults.

METHODS

The physiological and psychological effects of observing nature (visual observation of a money plant) on 50 older Chinese women (age range: 58-90 years, SD: 8.5 years) were investigated. The participants observed a healthy money plant in a planter for 5 min; the lack of presence of a plant was used as a control. Physiological measurements were assessed using electroencephalography, and the STAI was used as a psychological assessment.

RESULTS

After a 5-min observation of a money plant as compared with the control condition, systolic blood pressure significantly decreased, variations in both high alpha and high beta brainwaves were found, and psychological measurements revealed lower anxiety scores.

CONCLUSIONS

Our findings indicate that viewing a money plant for 5 min may enhance both psychological and physiological relaxation in older adults.

Acute EEG Patterns Associated With Transient Ischemic Attack

BACKGROUND

Transient ischemic attack (TIA) is characterized by stroke-like neurologic signs and symptoms in the absence of demonstrable structural neuropathology. There is no test for TIA, with classification often reliant on subjective, retrospective report. Functional brain measures such as the electroencephalogram (EEG) may be helpful in objectively detecting and describing the pathophysiology of TIA, but this has not been adequately examined.

METHODS

EEG was obtained from a single electrode over the left frontal lobe during 3-minute resting-state and auditory oddball conditions administered to consecutive patients within 72 hours of admission to the acute stroke ward of a tertiary hospital. Separately, patients were classified by their treating team as having suffered either an ischemic stroke (n = 10) or a TIA (n = 10). Relative power of delta, theta, alpha, and beta EEG frequency bands were extracted for comparison between the 2 clinical groups and an existing normative sample of 10 healthy, age-, gender-, and education-matched older adults.

RESULTS

Analysis of variance with post hoc testing identified pronounced delta activity in stroke patients, while alpha and beta power were elevated in TIA patients. Both patient groups exhibited attenuated theta activity compared with healthy controls. Receiver operating characteristic curve analysis identified thresholds for each EEG frequency capable of distinguishing the 3 participant groups.

CONCLUSIONS

TIA, ischemic stroke, and healthy aging are each associated with distinct electrophysiological profiles. These preliminary findings suggest that acute EEG may be helpful in elucidating the pathophysiology and reversibility of TIA symptoms, and further exploration of the value of this unique functional brain data is encouraged.

Physiological and psychological effects of gardening activity in older adults

AIM

Gardening has long been one of most enjoyable pastimes among older adults. Whether gardening activities contribute to the well-being of older adults is a major question. Therefore, the aim of the present study was to clarify the psychophysiological relaxing effects of gardening activities on older adults living in modern institutional care.

METHODS

The study participants were 40 older women aged 79.5 ± 8.09 years (mean ± SD). A cross-over study design was used to investigate the physiological and psychological responses to environments with and without plants. Physiological evaluation was carried out using blood pressure and electroencephalography, and psychological evaluation was carried out using the State-Trait Anxiety Inventory and Semantic Differential method.

RESULTS

Blood pressure was significantly lower, and changes in brainwaves were observed. Psychological responses showed that participants were more "comfortable and relaxed" after the plant task than after the control task. In addition, total anxiety levels were significantly lower after carrying out the plant task than after the control task.

CONCLUSIONS

Our research suggests that gardening activities might enhance physiological and psychological relaxation in older adults. Geriatr Gerontol Int 2018; 18: 1147-1152.

Psychometric and EEG changes after carotid endarterectomy

The influence of carotid stenosis and its surgical treatment on brain function is still poorly defined. We therefore performed a study to assess psychometric and quantified EEG findings after carotid endarterectomy (CEA). Sixty-nine non-demented patients (aged 72 ± 7 years) with severe carotid stenosis (≥ 70%) eligible for CEA were studied. Forty patients (group A) had unilateral stenosis, and 29 patients (group B) had bilateral stenosis. Before and 5 months after CEA all the patients were evaluated by the Trail Making Test A, the Symbol Digit Test, and spectral EEG analysis. At baseline, compared to group A, group B patients performed slowly the Trail Making Test A (Z: 1.45 ± 1.4 vs. 0.76 ± 1.3; p <  0.05), but not the Symbol Digit Test (Z: 0.83 ± 1.38 vs. 0.64 ± 1.26; p = 0.59). Altogether, the patients with at least one abnormal psychometric test were 29% (group A: 26%; group B: 33%, p = 0.56). The EEG did not differ significantly between patients of group A compared to group B. After CEA, psychometric tests improved (mean Z score from 0.73 ± 1.12 to 0.45 ± 1.15, p <  0.05). The improvement was similar in group A and B. The EEG mean dominant frequency improved only in group B patients and it was related to the improvement in psychometric tests (r = 0.43, p = 0.05). Low psychometric performance was detectable in about 1/ 3 of non-demented patients with severe carotid stenosis. CEA improved mental performance and, in patients with severe bilateral stenosis, accelerated the EEG frequency.

[French guidelines on electroencephalogram]

Electroencephalography allows the functional analysis of electrical brain cortical activity and is the gold standard for analyzing electrophysiological processes involved in epilepsy but also in several other dysfunctions of the central nervous system. Morphological imaging yields complementary data, yet it cannot replace the essential functional analysis tool that is EEG. Furthermore, EEG has the great advantage of being non-invasive, easy to perform and allows control tests when follow-up is necessary, even at the patient's bedside. Faced with the advances in knowledge, techniques and indications, the Société de Neurophysiologie Clinique de Langue Française (SNCLF) and the Ligue Française Contre l'Épilepsie (LFCE) found it necessary to provide an update on EEG recommendations. This article will review the methodology applied to this work, refine the various topics detailed in the following chapters. It will go over the summary of recommendations for each of these chapters and underline proposals for writing an EEG report. Some questions could not be answered by the review of the literature; in those cases, an expert advice was given by the working and reading groups in addition to the guidelines.

EEG of chronic marijuana users during abstinence: relationship to years of marijuana use, cerebral blood flow and thyroid function

OBJECTIVE

Marijuana abuse is associated with neurological changes including increases in frontal EEG alpha during abstinence. Research is needed to assess to what extent these EEG patterns are indicative of cerebral perfusion deficits.

METHODS

We recorded the resting eyes closed EEG of 75 abstinent marijuana users and 33 control subjects. Fifty-six marijuana users used marijuana for less than eight years and 19 used for eight years or more. The EEG evaluation occurred within 72h of admission to an inpatient unit. Fifty-nine marijuana users remained abstinent for a month and were tested twice. Supplemental psychological and physiological data were also collected.

RESULTS

Log alpha2 and beta2 power at posterior sites were significantly lower for the marijuana abusers that used eight years or more than the other marijuana abusers and the control subjects. These EEG changes continued for the month of abstinence. The marijuana users who used marijuana for more than eight years, also, had lower heart rates and thyroid function (T4) compared to the other marijuana users and the control subjects.

CONCLUSIONS

Chronic marijuana use was also associated with reduced EEG power in alpha and beta bands at posterior sites. These reductions in EEG power appear to be related to cerebral perfusion deficits and/or thyroid function in marijuana abusers.

SIGNIFICANCE

Our results suggest EEG, cerebral blood flow velocity, cardiovascular and thyroid function alterations in marijuana abuser with an extended period of use. These alterations reflect under arousal in these systems.

Classification of outcomes events in the Dutch TIA trial: prognostic value of accepted and rejected events

OBJECTIVE

In large multicentre clinical trials adjudication of outcome events most often is done centrally. Some of these events would eventually be judged not to meet the criteria and hence would be rejected. If the classification procedures work correctly one would expect a higher risk of future vascular events after an 'accepted' rather than after a 'rejected event. In the present study we aimed at testing the adequacy of a classification procedure in a trial of patients with a transient ischemic attack (TIA) or minor ischemic stroke by comparing the further outcome between patients in whom a possible event was either rejected or accepted for the final analysis in this trial.

RESEARCH DESIGN AND METHODS

The vascular outcome events were analysed in 3150 patients with TIA or minor stroke who participated in the Dutch TIA trial. We identified the patients with a first 'accepted' or 'rejected' non-fatal stroke or myocardial infarction (MI). In these two groups of patients we determined the occurrence of the subsequent vascular events (vascular death, stroke or MI). The incidence was compared with survival analysis techniques.

RESULTS

Among 308 patients with a first nonfatal 'accepted' event in 81 (26.3%) a new vascular event occurred; among the 51 patients with a 'rejected' event there were 12 (23.5%) such events. The hazard ratio for new vascular events was 1.22 (95% CI 0.67-2.22). After multivariate adjustment for age, type of qualifying event, history of smoking, angina pectoris and myocardial infarction, and Rankin score > or = 3, the hazard ratio was 1.49 (95% CI 0.78-2.84).

CONCLUSION

our study suggested that the adjudication process of outcome events in the Dutch TIA trial was done correctly because a trend towards a higher recurrence rate of vascular events among patients with 'accepted' outcome events was found.

A novel quantitative EEG injury measure of global cerebral ischemia

OBJECTIVE

To develop a novel quantitative EEG (qEEG) based analysis method, cepstral distance (CD) and compare it to spectral distance (SD) in detecting EEG changes related to global ischemia in rats.

METHODS

Adult Wistar rats were subjected to asphyxic-cardiac arrest for sham, 1, 3, 5 and 7 min (n=5 per group). The EEG signal was processed and fitted into an autoregressive (AR) model. A pre-injury baseline EEG was compared to selected data segments during asphyxia and recovery. The dissimilarities in the EEG segments were measured using CD and SD. A segment measured was considered abnormal when it exceeded 30% of baseline and its duration was used as the index of injury. A comprehensive Neurodeficit Score (NDS) at 24 h was used to assess outcome and was correlated with CD and SD measures.

RESULTS

A higher correlation was found with CD and asphyxia time (r=0.81, P<0.001) compared to SD and asphyxia time (r=0.69, P<0.001). Correlation with cardiac arrest time (MAP<10 mmHg) showed that CD was superior (r=0.71, P<0.001) to SD (r=0.52, P=0.002). CD obtained during global ischemia and 90 min into recovery correlated significantly with NDS at 24 h after injury (Spearman coefficient=-0.83, P<0.005), and was more robust than the traditional SD (Spearman coefficient=-0.63, P<0.005).

CONCLUSION

The novel qEEG-based injury index from CD was superior to SD in quantifying early cerebral dysfunction after cardiac arrest and in providing neurological prognosis at 24 h after global ischemia in adult rats. Studying early qEEG changes after asphyxic-cardiac arrest may provide new insights into the injury and recovery process, and present opportunities for therapy.

Quantitative EEG during early recovery from hypoxic-ischemic injury in immature piglets: burst occurrence and duration

This study examined the course of EEG recovery in an animal model of hypoxic-ischemic injury. The model used periods of hypoxia, room air and asphyxia to induce cardiac arrest. One-week-old piglets (n = 16) were exposed to a period of hypoxia, room air and complete asphyxia for 7 minutes. After cardiac arrest and resuscitation, two EEG features were evaluated as prognostic indicators of behavioral outcome as assessed by a neuroscore at 24 hours after insult. A prominent EEG feature was the number and duration of bursts evident during recovery. Episodes of bursting were detected through the thresholds on sustained periods of elevated power. After the animal was resuscitated, the EEG was monitored continuously for 4 hours. To assess outcome in the recovering animal, a behavioral testing scale was used to test the animal's neurological capabilities. Trends of EEG burst counts were measured through thresholds on sustained power changes. Bursts are energy transients in the EEG record. High degrees of bursting were characteristic of animals having good neurological condition whereas piglets having low burst counts had poor 24 hr neuroscores. At 100 min the average burst rate of the good neuroscore outcome group was more than 8 per min and was significantly different from the poor outcome group's level of 2.7 (p < or = 0.05). When these counts were weighted by their total duration, differences between groups increased (p < or = 0.02). This study showed that the QEEG measure of burst counts and duration together provided a strong prognostic indication of the 24 hour outcome after asphyxic injury in a neonatal animal model. The critical determinant of the bursting character was the time when bursting occurred. Bursting occurring early in recovery was a good gauge of outcome. We conclude that quantitative EEG analysis and interpretation can be an important tool for the outcome determination during recovery from cerebral injury states.

Ergoloids and ischaemic strokes; efficacy and mechanism of action

In this double-blind, randomized study the efficacy of the ergoloid compounds, co-dergocrine mesylate and nicergoline, in the rehabilitation of patients with ischaemic stroke was investigated. A group of 30 patients was treated daily with 60 mg nicergoline, orally, and a second group of 27 patients was given 1.8-6 mg co-dergocrine mesylate, orally or intramuscularly, daily (depending on the time since the initial ischaemic insult) for 6 months. Outcome measures included: motoricity index (limb function); Sandoz Clinical Assessment Geriatric (SCAG) scale; psychometric tests to assess functions such as attention, psychomotor performance, perception and sensory and short-term memory; conventional and computerized electroencephalography; and P300 and reaction time measures. The results showed improvements in some aspects such as limb function (P < 0.05), SCAG score (P < 0.01) and some electrophysiological parameters (P < 0.01) after treatment with both drugs. Though statistically significant most of the changes were not large. The efficacy of both drugs was qualitatively similar. The quantitative difference in some aspects in favour of nicergoline could be attributed to differences in the mechanisms of action of the two drugs, although it is also possible that the difference may reflect the dosages used. Nootropic drugs may induce a condition that facilitates the effects of cognitive training.