Posterior Dominant Rhythm Research Articles

P65-F EEG evolution in a case of rapidly progressive dementia

Background Rapidly progressive dementia can be caused by several factors like neurodegenerative, toxic/metabolic, infectious, autoimmune or neoplastic disorders. Here I present a case of this type and the diagnostic process leading to diagnosis. Material and methods This case describes a woman in her sixties admitted to hospital with dementia and anxiety as initial symptoWithin 2 month progression of these symptoms and appearance of apraxia, visual affection and cerebellar gait. The diagnostic process is illustrated. including consecutive EEGs, PET, MRi, CSF markers. Results Initial MRi was considered normal and first EEG with normal posterior dominant rhythm and bi-fronto-temporal 2–3 Hz activity (leftsided dominance) and no paroxystic activity. Repeated tests revealed classic changes seen in sporadic CJD on MRi in the form of cortical ribbon sign and adynamic periodic paroxyms and low frequency activity (2–3 Hz) lateralized in the EEG. CSF with normal count of protein and normal count of White blood cells and elevated count of total tau 1200 (normal range Conclusions Even though a definite diagnosis of Creutzfeldt-Jacob disease (CJD) can only be manifest by brain autopsy or biopsy post mortem a possible or likely diagnosis can be established combining CSF markers, brain imaging and EEG. This case illustrates the importance of EEG and especially consecutive EEGs in the diagnostic process of rapidly progressive dementia.

Phenotypic Characterization of Individuals with SYNGAP1 Pathogenic Variants Reveals Correlation Between Posterior Dominant Rhythm and Developmental Progression (P1.6-033)

Phenotypic Characterization of Individuals with SYNGAP1 Pathogenic Variants Reveals Correlation Between Posterior Dominant Rhythm and Developmental Progression (P1.6-033)

Continuous Electroencephalography After Moderate to Severe Traumatic Brain Injury.

After traumatic brain injury, continuous electroencephalography is widely used to detect electrographic seizures. With the development of standardized continuous electroencephalography terminology, we aimed to describe the prevalence and burden of ictal-interictal patterns, including electrographic seizures after moderate-to-severe traumatic brain injury and to correlate continuous electroencephalography features with functional outcome. Post hoc analysis of the prospective, randomized controlled phase 2 multicenter INTREPID study (ClinicalTrials.gov: NCT00805818). Continuous electroencephalography was initiated upon admission to the ICU. The primary outcome was the 3-month Glasgow Outcome Scale-Extended. Consensus electroencephalography reviews were performed by raters certified in standardized continuous electroencephalography terminology blinded to clinical data. Rhythmic, periodic, or ictal patterns were referred to as "ictal-interictal continuum"; severe ictal-interictal continuum was defined as greater than or equal to 1.5 Hz lateralized rhythmic delta activity or generalized periodic discharges and any lateralized periodic discharges or electrographic seizures. Twenty U.S. level I trauma centers. Patients with nonpenetrating traumatic brain injury and postresuscitation Glasgow Coma Scale score of 4-12 were included. None. Among 152 patients with continuous electroencephalography (age 34 ± 14 yr; 88% male), 22 (14%) had severe ictal-interictal continuum including electrographic seizures in four (2.6%). Severe ictal-interictal continuum burden correlated with initial prognostic scores, including the International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (r = 0.51; p = 0.01) and Injury Severity Score (r = 0.49; p = 0.01), but not with functional outcome. After controlling clinical covariates, unfavorable outcome was independently associated with absence of posterior dominant rhythm (common odds ratio, 3.38; 95% CI, 1.30-9.09), absence of N2 sleep transients (3.69; 1.69-8.20), predominant delta activity (2.82; 1.32-6.10), and discontinuous background (5.33; 2.28-12.96) within the first 72 hours of monitoring. Severe ictal-interictal continuum patterns, including electrographic seizures, were associated with clinical markers of injury severity but not functional outcome in this prospective cohort of patients with moderate-to-severe traumatic brain injury. Importantly, continuous electroencephalography background features were independently associated with functional outcome and improved the area under the curve of existing, validated predictive models.

Predictive values and specificity of electroencephalographic findings in autoimmune encephalitis diagnosis

ObjectiveEarly diagnosis of autoimmune encephalitis (AE) to not delay treatment is challenging but needed in practice. Most previous evidences of electroencephalographic (EEG) findings in AE were derived from descriptive studies. Given paucity of evidence of specific EEG findings to help with early diagnosis of AE, this study aimed to ascertain specific EEG findings and assess their predictive values in diagnosis of AE. MethodsWe included all cases with AE in our institution from January 2013 to June 2017. Cases were matched with controls by age and level of consciousness (1:2 ratio). Potential confounders for EEG findings collected as baseline characteristics were compared. Two epileptologists independently reviewed EEGs. Standardized terminology, definitions, and scoring system of EEG findings were employed. Logistic regression analysis was performed, and diagnostic performance of significant EEG features was assessed. ResultsTwenty cases and 40 controls were included in this study. Poorly sustained posterior dominant rhythm (PDR) was significantly associated with AE (p = 0.007) and even more predictive in anti-N-methyl-d-aspartate (NMDA) encephalitis. Inter-rater agreement (kappa) was 0.714. None of the cases had normal EEG nor Grand Total EEG (GTE) score < 4 (negative predictive value (NPV) of 100%). Specificity of well sustained PDR to exclude the diagnosis of anti-NMDA encephalitis was high (91.67%). ConclusionsSimple EEG assessment can be used to help exclude AE. When AE is suspected, careful assessment of the sustainment of the PDR is warranted. The NPV of GTE score < 4 and specificity of well sustained PDR can be simply used to differentiate many conditions from AE.

F81. Diagnosis of dementia and subtype classification by digital EEG: Is it also endorsed by automatic EEG analysis?

Introduction Precise diagnosis of subtypes of dementia is essential in daily medical practice. Electroencephalography (EEG) is a less expensive and non-invasive examination, but is not used for the diagnosis of dementia and its subtype classification because of lack of clear evidence. Therefore, we aimed at delineating clinical utility of EEG for this matter for Alzheimer disease (AD), dementia with Lewy body (DLB) and Parkinson disease with dementia (PDD). Methods We retrospectively analyzed the EEG data of 16 patients of AD (mean age ad SD = 67 ± 9.1-years, 6 male and 10 female) and 22 of synucleinopathy including 12 DLB and 10 PDD (72 ± 9.1-years, 17 male and 7 female) at Kyoto University Hospital from 2008 to 2015. First, by visual analysis we compared the posterior dominant rhythm (PDR) frequency and the ratio of generalized and regional slow waves between AD and synucleinopathy. Then, by automatic analysis we employed automatic EEG interpretation software (QP270 Nihonkoden) to investigate the same EEG parameters. Finally, we compared the results of visual analysis and automatic analysis in all patients. Results (1) With respect to the visual analysis, patients with synucleinopathy showed significantly lower PDR frequency (7.8 ± 1.0 Hz) than that of AD (9.2 ± 0.91 Hz) (p Conclusion In the visual analysis, EEG provides the information to differentiate AD from synucleinopathy by means of PDR, occipital slow waves and GS. The result of automatic analysis of EEG well matched with the visual analysis and there is a possibility that automatic EEG analysis was a useful tool to endorse the visual findings.

T60. Continuous EEG after moderate to severe traumatic brain injury: Seizures, ictal-interictal patterns and neurophysiologic predictors of functional outcome

Traumatic brain injury is common and the leading source of disability in the US. International guidelines for the use of EEG in those requiring ICU admission include indications to detect nonconvulsive seizures in those with altered mental status or in those at high-risk, although evidence is lacking for which patients might be at risk. Further, there is no evidence for the prognostic importance of continuous EEG (cEEG) in the context of established clinical indicators. We performed a post hoc analysis of data from the INTREPD2566 study (NCT00805818), a randomized controlled clinical trial of NNZ-2566, a synthetic neurotrophic IGF-1 derivative for moderate to severe TBI, defined as a Glasgow Coma Scale (GCS) score 4–12. This study failed to achieve its secondary end-point of modifying EEG. Per protocol, all patients received study drug or placebo within 8 h of injury; cEEG was initiated as soon as possible and continued for 72 h. Glasgow Outcome Scale-Extended data were collected at 3 months and dichotomized as good (GOSE 5–8) or poor (GOSE 1–4). A total n = 261 were initially enrolled; n = 38 were subsequently excluded from the study and n = 141/222 (63.5%) underwent cEEG monitoring. The mean age was 34 ± 15 years and 127/141 (90.1%) were men. The median post-resuscitation GCS was 7 (Interquartile Range 6–8) with a mean Injury Severity Score (ISS) of 23.6 ± 13.3. Mortality was 8.5% (12/141) at 3 months. The mean time from trauma to cEEG was 13.8 ± 9.8 h. Of those with data at 72 h, n = 24/120 (20%) had electrographic seizures, lateralized periodic discharges, or lateralized rhythmic discharges (SZ/LD); 4/120 had seizures alone. Only the presence of mass lesion on CT was associated with SZ/LD (OR 4.0, 95 CI 0.05–0.58; p = 0.01). Although n = 3/4 patients with seizures had poor outcome, there was no statistical association with outcome (OR2.9, 95 CI 0.22–154.60; NS); similarly, SZ/LD were observed equally between those with good and poor outcome. By contrast, the presence of a posterior dominant rhythm or sleep transients were associated with good outcome, while background delta frequencies were associated with poor outcome; superimposed background alpha/beta and burst-suppression (usually associated with sedation) were not associated with outcome. On multivariate analysis, only the ISS (OR 1.05, 95 CI 1.02–1.09) and an absence of sleep transients within 24 h (OR 4.61, 95 CI 2.14–9.94) were independently associated with poor outcome; the odds for poor outcome increased to 6.19 (95 CI 2.54–15.07) at 72 h without sleep transients. In this prospective cohort, we confirmed the incidence of seizures and focal periodic or rhythmic discharges and found an association with mass lesions on initial imaging. While seizures did not predict poor functional outcome, we found an independent association with the absence of identifiable sleep transients at 24 and 72 h.

Diagnostic yield of standard-wake and sleep EEG recordings

ObjectiveTo investigate whether Posterior Dominant Rhythm (PDR) can be reliably assessed in sleep-EEG recordings and to investigate the diagnostic yield of standard-wake and sleep-recordings. MethodsEEG recordings of 303 consecutive patients aged 18–88 years were analyzed. All patients had both standard-wake and sleep-recordings, including patients who had abnormal standard recordings. Melatonin was used in 6% of sleep EEGs, and sleep deprivation in 94%. The mean duration of sleep was 41 min. We measured the PDR frequency in standard and sleep-recordings, both before and after sleep. We compared the diagnostic yield of standard-wake and sleep EEG recordings. ResultsCompared to standard EEG, sleep-recordings showed a significantly lower PDR frequency, both when measured before and after sleep (p < 0.001). One-hundred-fifty-six patients (51%) had normal standard recordings, and 35 of them (22%) had abnormal findings in the sleep-recording. One-hundred-forty-seven patients had abnormal standard recordings and in 16 of them (11%) these abnormalities were not present in sleep-recording. ConclusionsPDR is significantly slower in the wake periods of sleep-recordings, compared to standard wake recordings. SignificanceSleep and standard wake recordings are complementary.

The Encephalophone: A Novel Musical Biofeedback Device using Conscious Control of Electroencephalogram (EEG).

A novel musical instrument and biofeedback device was created using electroencephalogram (EEG) posterior dominant rhythm (PDR) or mu rhythm to control a synthesized piano, which we call the Encephalophone. Alpha-frequency (8–12 Hz) signal power from PDR in the visual cortex or from mu rhythm in the motor cortex was used to create a power scale which was then converted into a musical scale, which could be manipulated by the individual in real time. Subjects could then generate different notes of the scale by activation (event-related synchronization) or de-activation (event-related desynchronization) of the PDR or mu rhythms in visual or motor cortex, respectively. Fifteen novice normal subjects were tested in their ability to hit target notes presented within a 5-min trial period. All 15 subjects were able to perform more accurately (average of 27.4 hits, 67.1% accuracy for visual cortex/PDR signaling; average of 20.6 hits, 57.1% accuracy for mu signaling) than a random note generation (19.03% accuracy). Moreover, PDR control was significantly more accurate than mu control. This shows that novice healthy individuals can control music with better accuracy than random, with no prior training on the device, and that PDR control is more accurate than mu control for these novices. Individuals with more years of musical training showed a moderate positive correlation with more PDR accuracy, but not mu accuracy. The Encephalophone may have potential applications both as a novel musical instrument without requiring movement, as well as a potential therapeutic biofeedback device for patients suffering from motor deficits (e.g., amyotrophic lateral sclerosis (ALS), brainstem stroke, traumatic amputation).

Traumatic brain injury: An EEG point of view.

Traumatic brain injury (TBI) is a silent epidemic. Mild traumatic brain injury (mTBI) causes brain injury that results in electrophysiologic abnormalities visible on electroencephalography (EEG) recordings. The purpose of this brief review was to discuss the importance of EEG findings in traumatic brain injury. Relevant articles published during the 1996-2016 period were retrieved from Medline (PubMed). The keywords were in English and included "traumatic brain injury", "EEG" and "quantitative EEG". We found 460 articles, analyzed 52 and selected 13 articles. EEG after TBI shows slowing of the posterior dominant rhythm and increased diffuse theta slowing, which may revert to normal within hours or may clear more slowly over many weeks. There are no clear EEG or quantitative EEG (qEEG) features unique to mild traumatic brain injury. Although the literature indicates the promise of qEEG in reaching a diagnosis and indicating prognosis of mTBI, further study is needed to corroborate and refine these methods.

Benign adult familial myoclonus epilepsy is a progressive disorder: no longer idiopathic generalized epilepsy.

Brain dysfunction in Japanese benign adult familial myoclonus epilepsy (BAFME) has not been elucidated. To clarify diffuse brain dysfunction as indicated by posterior dominant rhythm (PDR) slowing in patients with BAFME. The frequency of PDR on EEG was studied in 19 BAFME patients (50.6±15.7years) and 38 age-matched control subjects (50.1±14.5years). We investigated the relationship between age and PDR in both groups. PDR frequency in the patient group (9.1±0.7Hz) was significantly slower than that of age-matched control subjects (10.4±1.1Hz; p<0.0001), regardless of the use of anticonvulsants. There was no significant difference in PDR slowing with age between groups. These findings suggest that Japanese patients with BAFME have mild diffuse brain dysfunction with minimal progression.

Quantification of the adult EEG

Objective Automated analysis of the background EEG pattern and detection of inter-ictal epileptiform discharges may assist clinicians in faster and more efficient reviews. We aim to find automated techniques that will assist with visual interpretation, improve efficiency and lower inter- and intra-rater reliability. Methods For EEG background pattern analysis, five common properties were investigated: posterior dominant rhythm, (a)symmetry, reactivity, anterior–posterior differentiation and diffuse slow waves. Guidelines for quantifying each property were defined and translated into computer algorithms. In addition, a template matching technique was used for spike detection with 2160 real-world examples of inter-ictal spikes. The proposed algorithm learns from its mistakes by remembering outcomes and rewarding good predictions. Results Background analysis was evaluated by 10 experienced neurologists: 80% found it helped prevent mistakes, 50% said it saved time, and all found the generated reports useful and would use the algorithms in clinical practice. For automated spike detection, 95% of inter-ictal events were found per EEG (evaluation set of 15 EEGs) with approximately 5 min of review time per recording. Key message Quantitative EEG and automated analysis is well received if implemented correctly. It will not yet replace visual analysis completely, but as assistant brings valuable contributions to reviews.

The additional lateralizing and localizing value of the postictal EEG in frontal lobe epilepsy

ObjectiveThe aim of this study was to describe the additional lateralizing and localizing value of the postictal EEG in frontal lobe epilepsy (FLE). The ictal EEG in FLE is frequently challenging to localize. MethodsWe identified patients investigated for epilepsy surgery with unilateral FLE based on consistent semiology, a clear lesion and/or with frontal onset on intracranial EEG. A one hour section of postictal EEG was analyzed by two raters for new or activated EEG features and it was assessed whether these features offered additional information when compared to the ictal EEG. Postictal features assessed included asymmetrical return of the posterior dominant rhythm and potentiated lateralized or regional frontal slowing, spikes or sharp waves. ResultsThirty-eight patients were included who had a combined total of ninety-six seizures. 47/96 (49%) postictal periods contained correctly lateralizing or localizing information. The sensitivity for asymmetrical return of the posterior dominant rhythm was 24%. The sensitivity for regional frontal slow and frontal spikes was 23% and 20% respectively. Further analysis showed that in 14/38 (39%) patients, at least one seizure with an unhelpful ictal EEG was followed by postictal EEG features that added new localizing or lateralizing information. A subgroup of 11 patients who were ⩾1year seizure-free (ILAE class 1) and thus classified as having a ‘gold-standard’ FLE diagnosis were analyzed separately and it was found that 14/30 of their seizures (47%) had extra postictal information. ConclusionsThe new postictal information was always concordant with the ultimate diagnosis, except for asymmetric postictal return of background activity ipsilateral to the epileptogenic zone in three patients. SignificanceThis study shows that a close examination of the postictal EEG can offer additional information which can contribute to the identification of a potentially resectable epileptogenic zone.

Characteristics and role in outcome prediction of continuous EEG after status epilepticus: A prospective observational cohort.

Continuous electroencephalography (cEEG) is important for treatment guidance in status epilepticus (SE) management, but its role in clinical outcome prediction is unclear. Our aim is to determine which cEEG features give independent outcome information after correction for clinical predictor. cEEG data of 120 consecutive adult patients with SE were prospectively collected in three academic medical centers using the 2012 American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology. Association between cEEG features and two clinical outcome measures (mortality and complete recovery) was assessed. In the first 24 h of EEG recording, 49 patients (40.8%) showed no periodic or rhythmic pattern, 45 (37.5%) had periodic discharges, 20 (16.7%) had rhythmic delta activity, and 6 (5%) had spike-and-wave discharges. Seizures were recorded in 68.3% of patients. After adjusting for known clinical predictive factors for mortality including the STatus Epilepticus Severity Score (STESS) and the presence of a potentially fatal etiology, the only EEG features (among rhythmic and periodic patterns, seizures, and background activity) that remained significantly associated with outcome were the absence of a posterior dominant rhythm (odds ratio [OR] 9.8; p = 0.033) for mortality and changes in stage II sleep pattern characteristics (OR 2.59 for each step up among these categories: absent, present and abnormal, present and normal; p = 0.002) for complete recovery. After adjustment for relevant clinical findings, including SE severity and etiology, cEEG background information (posterior dominant rhythm and sleep patterns) is more predictive for clinical outcome after SE than are rhythmic and periodic patterns or seizures.

Acute EEG findings in HIV-infected Zambian adults with new-onset seizure.

To describe acute EEG findings in HIV-infected adults with new-onset seizure, assess baseline clinical characteristics associated with EEG abnormalities, and evaluate the relationship between EEG abnormalities and recurrent seizure. Eighty-one HIV-infected adults with new-onset seizure had EEG recordings during their index admission. Baseline characteristics assessed included HIV stage, seizure semiology, serum and CSF studies, neuroimaging, cognitive function based on the Zambian Mini-Mental State Examination and International HIV Dementia Scale, and psychiatric symptoms using the Shona Symptom Questionnaire. We evaluated the relationship between baseline characteristics and EEG abnormalities. Patients were followed for seizure recurrence, and the association between acute EEG abnormalities and seizure recurrence was assessed. Death was a secondary outcome. Fifty-five patients had abnormal EEGs (68%): 18 (22%) had interictal spikes (12) or a recorded seizure (6). Among baseline clinical characteristics, more advanced HIV disease (p = 0.039) and any imaging abnormality (p = 0.027) were associated with abnormal EEGs. Cortical (p = 0.008) and white matter (p = 0.004) abnormalities were associated with slow posterior dominant rhythm. Patients were followed for a median of 303 days (interquartile range 103-560). Twenty-four (30%) died and 23 (28%) had recurrent seizures. EEG abnormalities were not associated with recurrent seizure. There was a nonsignificant association between seizures recorded during EEG and death (67% vs 26%, p = 0.051). EEG abnormalities are common in this population, particularly in patients with imaging abnormalities and advanced HIV. Acute EEG abnormalities were not associated with recurrent seizure, but high mortality rates during follow-up limited this analysis.

Sleep in the neurological intensive care unit: feasibility of quantifying sleep after melatonin supplementation with environmental light and noise reduction.

Sleep deprivation may be particularly detrimental to intensive care unit (ICU) patients. Polysomnography has demonstrated abnormal sleep in medical and surgical ICU populations. Both environmental factors and circadian disruption have been implicated. We hypothesized that patients in a neurologic ICU would demonstrate similar sleep disturbances and that a combination of sleep-promoting interventions would increase sleep time. Twelve patients were enrolled in this pilot-randomized, controlled, study in a neurologic ICU. For adult patients undergoing continuous EEG for clinical purposes, noise-cancelling headphones and eye masks were worn, and an oral dose of melatonin was administered for 3 days, or until EEG was stopped. Sleep was scored according to standard criteria; EEG was characterized and analyzed quantitatively. Sixty-five percent of the patients' recordings were unscorable based on accepted standardized criteria; therefore, sleep measures could not be compared. For those with sleep that could be scored, total sleep time was normal, although sleep was fragmented and time spent in slow-wave or rapid eye movement sleep was notably decreased. Patients with unscorable recordings had worse injury severity measures, absent or significantly slower posterior dominant rhythm, and less coherence of posterior faster frequencies. Clinical outcomes were similar between intervention and control groups. Although sleep-promoting interventions were feasible, sleep quantification based on currently accepted criteria limited the ability to score sleep. Similar to other ICUs, sleep in the neurologic ICU is abnormal; patients with unscorable sleep-like states have greater injury severity. This study was limited by strict enrollment criteria. A reliable method to quantify sleep and sleep-like states in the ICU is needed.

Alpha-band desynchronization in human parietal area during reach planning

ObjectiveThe symptoms with optic ataxia suggest that simple and visually guided hand movements are controlled by 2 different neural substrates. To assess the differential frequency-coded posterior parietal cortex (PPC) role in planning visuo-motor goal-directed tasks, we studied the action specificity of event-related desynchronization (ERD) in this area. MethodsWe investigated cortical activity by electroencephalography, while 16 healthy subjects performed self-paced reaching or wrist extension (control) movements. Time–frequency representations were calculated for each movement during the preparatory period. ResultsERD dynamics in upper alpha-band indicated that preparing a goal-directed action activates contralateral PPC to the moving hand around 1.2s before starting the movement, while this activation is later (around 0.7s) in preparing a not-goal-directed action. The posterior dominant rhythm had peak frequency of lower alpha-band at bilateral parietal. ConclusionsPosterior parietal cortex encodes goal-directed movement preparation through upper alpha-band activity, whereas general attention is processed via lower alpha-band oscillations. SignificancePreparing to reach an object engages posterior parietal cortex earlier than a not-goal directed movement.

Comparison of the effects of transdermal and oral rivastigmine on cognitive function and EEG markers in patients with Alzheimer's disease.

Background: Alzheimer’s disease (AD) is the most common cause of dementia in older patients. Rivastigmine (RV, Exelon, Novartis), a reversible cholinesterase inhibitor, improves clinical manifestations of AD and may enhance ACh-modulated electroencephalogram (EEG) alpha frequency. This pilot study aimed to determine the effects of two formulations of RV [transdermal patch (RV-TDP) and oral capsules (TV-CP)] on alpha frequency, in particular the posterior dominant rhythm, and cognitive function [assessed by the Mini-Mental State Examination (MMSE)] in patients with AD.Methods: Subjects with AD were assigned to receive either RV-TDP 10 cm2 or RV-CP 12 mg/day. All patients underwent EEG recordings at the beginning and end of the 18-month study period using P3, P4, O1, and O2 electrodes, each at high (10.5–13.0 Hz) and low (8.0–10.5 Hz) frequency. MMSE scores were determined at the start of the study (T0) and at three successive 6-month intervals (T1, T2, and T3).Results: RV-TDP administration (n = 10) maintained cognitive function as evidenced by stable MMSE scores from baseline to 18 months (21.07 ± 2.4–21.2 ± 3.1) compared with a decrease in MMSE score with RV-CP (n = 10) over 18 months [18.3 ± 3.6–13.6 ± 5.06 (adjusted for covariates p = 0.006)]. MMSE scores were significantly different between treatment groups from 6 months (p = 0.04). RV-TDP also increased the spectral power of alpha waves in the posterior region measured with electrode P3 in a significantly great percentage of patients than TV-CP from baseline to 18 months; 80% vs 30%, respectively [p = 0.025 (χ2 test)].Conclusions: RV-TDP was associated with a greater proportion of patients with increased posterior region alpha wave spectral power and significantly higher cognitive function at 18 months, compared with RV-CP treatment. Our findings suggest that RV-TDP provides an effective long-term management option in patients with AD compared with oral RV-CP. This study is a pilot, open-label study with a clear explorative purpose and with a small number of patients. Further randomized, double-blind, placebo-controlled trial studies with a bigger sample size as well as healthy controls are needed to support these initial results.

EEG abnormalities and seizures in genetically diagnosed Fragile X syndrome

We describe the seizure and EEG characteristics in a population of children with known Fragile X. The medical records of 135 genetically confirmed FXS patients receiving care in a Fragile X clinic and their available EEG reports were reviewed. The mean age was 5.94 years old including 18 males and 1 female. The mean age was 4–9 years old with an age range of 15 months to 13 years old. Twenty-two patients (16.3%) in the series had parent-reported behavior suspicious of seizures. Sixteen patients (14.1%, 1 female) had at least one EEG recorded for evaluation of clinical events suspicious for seizure, and three patients (2.2%) had an EEG in the context of a polysomnography for diagnosing sleep apnea. The mean age at EEG evaluation was 6.0 years (standard deviation 3.8 years). EEG findings included slowing of background rhythm (n=9) and epileptiform discharges (n=7). Four patients had normal EEGs (n=4). Six patients (4.4% of the sample population) were diagnosed with epilepsy by both clinical seizure semiology and documented EEG abnormalities. Thirteen patients (68.4% of total) had episodes of staring and behavioral arrest with no EEG correlate, indicating non-epileptic events. Of the eight patients who underwent a repeat EEG, five patients had showed normalization in the posterior dominant rhythm over time, two patients had unchanged findings and one patient had worsening of his EEG. Our data warrant further prospective validation.

P459: Electro-clinical features of focal epilepsy patients with postictal generalized EEG suppression

P459: Electro-clinical features of focal epilepsy patients with postictal generalized EEG suppression

Computer-Assisted Interpretation of the EEG Background Pattern: A Clinical Evaluation

ObjectiveInterpretation of the EEG background pattern in routine recordings is an important part of clinical reviews. We evaluated the feasibility of an automated analysis system to assist reviewers with evaluation of the general properties in the EEG background pattern.MethodsQuantitative EEG methods were used to describe the following five background properties: posterior dominant rhythm frequency and reactivity, anterior-posterior gradients, presence of diffuse slow-wave activity and asymmetry. Software running the quantitative methods were given to ten experienced electroencephalographers together with 45 routine EEG recordings and computer-generated reports. Participants were asked to review the EEGs by visual analysis first, and afterwards to compare their findings with the generated reports and correct mistakes made by the system. Corrected reports were returned for comparison.ResultsUsing a gold-standard derived from the consensus of reviewers, inter-rater agreement was calculated for all reviewers and for automated interpretation. Automated interpretation together with most participants showed high (kappa > 0.6) agreement with the gold standard. In some cases, automated analysis showed higher agreement with the gold standard than participants. When asked in a questionnaire after the study, all participants considered computer-assisted interpretation to be useful for every day use in routine reviews.ConclusionsAutomated interpretation methods proved to be accurate and were considered to be useful by all participants.SignificanceComputer-assisted interpretation of the EEG background pattern can bring consistency to reviewing and improve efficiency and inter-rater agreement.