Contribution of EEG in transient neurological deficits

Contribution of the EEG in the Diagnostic Workup of Patients with Transient Neurological Deficit and Acute Confusional State at the Emergency Department: The EMINENCE Study

Background/Objectives: To investigate the usefulness of an emergency electroencephalogram (emEEG) in the differential diagnosis of transient neurological deficits (TND) and acute confusional state (ACS). Methods: An analysis was performed on a subset of patients included in EMINENCE, a retrospective study of subjects admitted to the Emergency Department (ED) of our tertiary hospital over a 1-year period. The analysis was limited to patients with neurological symptoms/signs compatible with cerebral hemispheric origin or with an ACS of <24 h duration. We evaluated the usefulness of the emEEG in the diagnostic workup of TND and ACS. Results: Speech disorder (75.3%), hyposthenia (68.1%), and ACS (62.9%) were the signs/symptoms with the highest percentage of abnormal emEEGs, especially concerning epileptic discharges. Seizures (85.7%) and encephalopathy (74.3%) were the final diagnoses with the highest percentage of abnormal emEEGs, particularly epileptic discharges and focal slow waves in patients discharged with a diagnosis of seizures, and bilateral slow waves and generalized periodic discharges with triphasic morphology (GPDTM) in patients discharged with a diagnosis of encephalopathy. The presence/absence of epileptic discharges associated with focal slow waves could discriminate between seizures and vascular disease, especially in hyposthenia (100% of seizures when epileptic discharges were present, vs. 50% when absent). Migraine with aura (66%) and an unknown diagnosis (56%) were the final diagnoses with the most normal emEEG. The rapid timing of the emEEG recording compared to the patient's admission allowed us to perform the test in 29.5% of patients who were still symptomatic, of whom 79% had an abnormal emEEG. Conclusions: The emEEG mainly contributed to the diagnosis when speech disorder, hyposthenia, and ACS were the admission signs/symptoms, especially for the final diagnosis of seizures and encephalopathy.

The role of EEG in the emergency department: Its contribution to the patient's diagnostic-therapeutic pathway. The EMINENCE study

Objectives

To investigate the utility of the emergency electroencephalogram(emEEG) in the diagnostic work-up of patients admitted to the Emergency Department(ED).

Methods

Data from consecutive patients admitted to the ED during a 1-year period. We evaluated the usefulness of emEEGs based on the subsequent patient clinical management.

Results

1125 emEEGs from 1018 patients were analyzed. The overall usefulness of an emEEG was 86.7%, mainly influenced by its contribution to diagnosis(75.0%), often excluding initial working diagnosis(50.0%), and to patient management(78.0%). EmEEGs showed their best overall usefulness in Status Epilepticus(SE) and altered level of consciousness both in contributing to the final diagnosis and in patient management and therapeutic pathway. In speech and cognitive/behavioural disorders, emEEGs contributed to the diagnosis(80.6% and 79.8%, respectively), often excluding the initial suspicion of seizures/SE. Normal emEEGs contributed to diagnosis(79.0%), patient management(87.0%) and discharge to home(82.0%).

Conclusions

In ED, attending physicians have to make quick decisions about the diagnostic-therapeutic management of patients, and also the ruling out of the initial diagnosis and safely discharging the patient to home are also important goals.

Significance

This study provides valuable guidance to ED clinicians in selecting patients for an emEEG and evaluates its contribution to their diagnostic-therapeutic management.

Transient headache and neurological deficits with cerebrospinal fluid lymphocytosis syndrome: A comprehensive systematic review of 93 patients from 57 studies

BACKGROUND

Headache with neurologic deficits and cerebrospinal fluid lymphocytosis, previously also termed pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis, is a self-limiting syndrome characterized by moderate to severe headache associated with focal neurological deficits occurring in the context of lymphocytosis in the cerebrospinal fluid. As a consequence of its rarity, data regarding headache with neurologic deficits and cerebrospinal fluid lymphocytosis is sparse. Therefore, we conducted this review to analyze data related to 93 patients of headache with neurologic deficits and cerebrospinal fluid lymphocytosis, to characterize their demographics, clinical manifestations, investigations and treatment options.

METHODS

We performed a systematic review of cases reported through PubMed and Google scholar database, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Keywords used were 'Headache with Neurologic Deficits and cerebrospinal fluid lymphocytosis', 'Headache with neurologic deficits and cerebrospinal fluid lymphocytosis syndrome'. The quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal Tool.

RESULTS

We analyzed a total of 93 cases of headache with neurologic deficits and cerebrospinal fluid lymphocytosis with a mean age of 28.8 years at onset. Seventy patients (75.2%) were adults, while 23 (24.7%) belonged to the pediatric age group. Comparing these groups, mean age at onset was 32.5 years and 14.3 years, respectively. The average duration of follow-up was 11.08 months. Thirty percent of patients experienced relapsing episodes of headache with neurologic deficits and cerebrospinal fluid lymphocytosis symptoms. The most common type of headache reported was unilateral severe throbbing episodic headache. Other associated symptoms included sensory deficit (60%) and motor deficits (54.8%). The least common symptoms were nystagmus and agraphia, which were reported in one patient each. Antiviral agents were a common treatment option in the acute phase (n  =  23 patients [23.6%]), while Flunarizine was the most commonly used agent in the chronic setting (n = 3 patients [3.2%]). While most of the patients had normal brain magnetic resonance imaging, 20 patients had magnetic resonance imaging abnormalities, including (but not limited to) non-specific white matter lesions (eight patients) and meningeal enhancement (six patients). The most common electroencephalographic findings included diffuse and focal slowing. The mean cerebrospinal fluid opening-pressure was 240.5 mmH₂O. Cerebrospinal fluid protein was elevated in 59 (63.4%) patients, with a mean value of 114 mg/dL. Two patients in our cohort were found to have cerebrospinal fluid oligoclonal bands.

CONCLUSION

Headache with neurologic deficits and cerebrospinal fluid lymphocytosis tends to affect young individuals with a slight male predominance. Unilateral severe throbbing episodic headache with associated hemi-paresthesia and hemiparesis were the most common symptoms based on our review. Elevated cerebrospinal fluid opening-pressure can be seen in headache with neurologic deficits and cerebrospinal fluid lymphocytosis syndrome. Early recognition of the syndrome is paramount. Antivirals were found to be among the most widely used treatments in the acute setting. Magnetic resonance imaging of the brain is mostly normal. Diffuse and focal slowing were among the most common electroencephalographic findings. Cerebral flow abnormalities on perfusion scans are not uncommon in headache with neurologic deficits and cerebrospinal fluid lymphocytosis. Prospective studies with a larger sample size are needed to validate our findings and guide the clinical care of these patients.

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.

Kopfschmerz bei Parietal- und Okzipitallappenepilepsien

Epilepsiepatienten leiden überdurchschnittlich häufig unter Kopfschmerzen. Dies gilt insbesondere für Patienten mit idiopathisch generalisierten und parietookzipitalen Epilepsien. Die Häufigkeit des gemeinsamen Auftretens von Kopfschmerzen und Epilepsie überschreitet dabei die rechnerische Koinzidenz, sodass von einer Komorbidität beider Syndrome auszugehen ist. Bestärkt wird diese Hypothese durch überlappende genetische Veränderungen sowie gemeinsame pathophysiologische Mechanismen. Bis zu 62 % der Patienten mit z. B. Parietal- und Okzipitallappenepilepsie (POLE) geben Kopfschmerzen an. Diese treten v. a. nach dem Anfall (postiktal) auf und manifestieren sich am häufigsten als Migräne-ähnlicher Kopfschmerz oder Spannungskopfschmerz. Seltener kommt es zu Kopfschmerzen vor (periiktal), während (iktal) oder zwischen (interiktal) epileptischen Anfällen. Bei transienten neurologischen Ausfallsymptomen mit begleitenden Kopfschmerzen ist differenzialdiagnostisch neben der Migräne an vaskuläre Ereignisse wie Synkopen oder eine transiente ischämische Attacke zu denken.

An update on EEG in migraine

Introduction: In the past few years, brain functional analysis has provided scientific evidence supporting the neuronal basis of migraine. The role of electroencephalography (EEG) in detecting subtle dysfunctions in sensory temporal processing has been fully re-evaluated, thanks to advances in methods of quantitative analysis. However, the diagnostic value of EEG in migraine is very low, and migraine diagnosis is completely based on clinical criteria, while the utility of EEG in migraine pathophysiology has only been confirmed in more recent applications. Areas covered: The present review focuses on the few situations in which EEG may provide diagnostic utility, and on the numerous and intriguing applications of novel analysis, based on time-related changes in neuronal network oscillations and functional connectivity. Expert opinion: Although routine EEG is not particularly useful for the clinical assessment of migraine, novel methods of analysis, mostly based on functional connectivity, could improve knowledge of the migraine brain. The application is worthy of promotion and improvement in support of neuroimaging data to shed light on migraine mechanisms and support the rationale for therapeutic approaches.