Multimodal mapping and monitoring is beneficial during awake craniotomy for intra-cranial tumours: results of a dual centre retrospective study.

BACKGROUND: The combination of awake craniotomy with multimodal neurophysiological mapping and monitoring in intra-axial tumour resection is not well described, but may have theoretical benefits which we sought to investigate. METHODS: All patients undergoing awake craniotomy for tumour resection with cortical and/or subcortical stimulation together with one or more of electrocorticography (ECoG/EEG), motor or somatosensory evoked potentials were identified from the operative records of two surgeons at two centres over a 5 year period. Patient, operative and outcome data were collated. Statistical analysis was performed to evaluate factors predictive of intra-operative seizures and surgical outcomes. RESULTS: 83 patients with a median age 50 years (18-80 years) were included. 80% had gliomas (37% low grade) and 13% metastases. Cortical mapping was negative in 35% (language areas) and 24% (motor areas). Complete or near total resection was achieved in 80% with 5% severe long-term neurological deficits. Negative cortical mapping was combined with positive subcortical mapping in 42% with no significant difference in extent of resection rates to patients undergoing positive cortical mapping (p = 0.95). Awake mapping could not be completed in 14%, but with no compromise to extent of resection (p = 0.55) or complication rates (p = 0.09). Intraoperative seizures occurred in 11% and were significantly associated with intra-operative EEG spikes (p = 0.003). CONCLUSIONS: Awake multi-modal monitoring is a safe and well tolerated technique. It provides preservation of extent of resection and clinical outcomes in cases of aborted awake craniotomy. Negative cortical mapping in combination with positive subcortical mapping was also shown to be safe, although not hitherto well described. Electrocorticography further enables the differentiation of seizure activity from true positive mapping, and the successful treatment of spikes prior to full clinical seizures occurring.

Home video telemetry in children: A comparison to inpatient video telemetry.

PURPOSE: Home Video Telemetry (HVT) combines ambulatory EEG with simultaneous video recording. No previous reports have compared HVT and inpatient video telemetry (IVT) in a purely paediatric population. This study compares HVT and IVT in this group in terms of diagnostic efficacy, recording quality and acceptability to parents/carers. METHODS: 33 HVT and 29 IVT patients aged 1-17 years were included. Information regarding patient demographics, ictal capture, diagnostic utility, recording quality (e.g. video clarity, EEG artefacts) and parent/carer preferences was documented. Difficulties using HVT equipment were recorded. RESULTS: 62% of IVT patients and 64% of HVT patients had typical attacks during the recording. 59% of IVT and 70% of HVT recordings were considered to have answered the referral question. Study quality was similar in both groups. In HVT studies the rate of equipment difficulties was 52%; problems included camera positioning and failure to turn on the infrared button at night. Diagnostic information was lost in 15% of patients. 76% of parents/carers of HVT patients would choose this investigation again. CONCLUSIONS: The diagnostic efficacy and study quality of HVT and IVT are similar in paediatric patients. HVT is acceptable to most parents/carers. User error may compromise the investigation in a minority of cases but did not impact on diagnostic utility. Adoption of HVT investigation could provide an accessible and economic alternative to IVT.

Early Seizure Detection Based on Cardiac Autonomic Regulation Dynamics.

Epilepsy is a neurological disorder that causes changes in the autonomic nervous system. Heart rate variability (HRV) reflects the regulation of cardiac activity and autonomic nervous system tone. The early detection of epileptic seizures could foster the use of new treatment approaches. This study presents a new methodology for the prediction of epileptic seizures using HRV signals. Eigendecomposition of HRV parameter covariance matrices was used to create an input for a support vector machine (SVM)-based classifier. We analyzed clinical data from 12 patients (9 female; 3 male; age 34.5 ± 7.5 years), involving 34 seizures and a total of 55.2 h of interictal electrocardiogram (ECG) recordings. Data from 123.6 h of ECG recordings from healthy subjects were used to test false positive rate per hour (FP/h) in a completely independent data set. Our methodological approach allowed the detection of impending seizures from 5 min to just before the onset of a clinical/electrical seizure with a sensitivity of 94.1%. The FP rate was 0.49 h-1 in the recordings from patients with epilepsy and 0.19 h-1 in the recordings from healthy subjects. Our results suggest that it is feasible to use the dynamics of HRV parameters for the early detection and, potentially, the prediction of epileptic seizures.

Video ambulatory EEG: A good alternative to inpatient video telemetry?

PURPOSE: Video ambulatory EEG (V-AEEG) is a new technique which could add increased capacity for long term EEG monitoring to overstretched inpatient video telemetry (IPVT) services. We compare V-AEEG and IPVT for diagnostic efficacy, recording quality, patient acceptability and technologist time required. METHODS: Forty-one V-AEEG and 64 IPVT adult patients were included. Patients were investigated to diagnose attacks or to obtain polysomnography (PSG) prior to multiple sleep latency test (MSLT). Number of attacks recorded, whether the diagnostic question was answered, quality of video and EEG recording and patients' preference for investigation at home or in hospital were noted. For V-AEEG patients, ease of procedure and extra technologist time required were recorded. RESULTS: Of patients investigated for diagnosis of attacks, 74% V-AEEG patients and 62% IPVT had typical attacks during the investigation. All PSGs were useful in interpreting the MSLTs. Diagnostic questions were answered by 73% V-AEEGs and 73% IPVTs. Quality of EEG and video recording was similar using V-AEEG and IPVT. Four patients had difficulty using V-AEEG equipment but diagnostic information was lost in only one. 5% of V-AEEG patients would have preferred hospital investigation but 45% of IPVT patients would have preferred home investigation. Extra technologist time for home visits (mean 2h) was required only for the first 7 patients. CONCLUSION: Video EEG recording quality and diagnostic efficacy from V-AEEG are similar to IPVT. V-AEEG is acceptable to most patients and does not require additional technical time. Hence, V-AEEG offers a convenient, economical alternative to IPVT.

Brief rhythmic discharges in neonates: a marker for seizures.

Brief rhythmic discharges (BRDs) are paroxysms of rhythmic electrographic activity with an amplitude of >2 µV and a duration of <10 seconds. Although BRDs are reported in neonates, this electrographic activity contrasts the accepted definition of neonatal seizures (duration of >10 seconds). BRDs are associated with background EEG abnormalities as well as increased morbidity and mortality (Oliveira et al., 2000, Nagarajan et al., 2011), and appear to be more closely related to formal neonatal seizures than post-neonatal epilepsy (Nagarajan et al., 2011). Most neonatal units are restricted to one-hour recordings, and if BRDs are observed without any accompanying electrographic seizures, then the neonate should be regarded as being at high risk of seizures and repeat recordings should be considered.

Cataplectic facies: clinical marker in the diagnosis of childhood narcolepsy-report of two cases.

BACKGROUND: Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood and/or adolescence. The full spectrum of clinical manifestations, namely excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis, is usually not present at disease onset, delaying diagnosis during childhood. Mean delay in diagnosis since symptom onset is known to be several years. Initial manifestations can sometimes be as subtle as only partial drooping of eyelids leading to confusion with a myasthenic condition. PATIENTS: We present two children who presented with "cataplectic facies," an unusual facial feature only recently described in children with narcolepsy with cataplexy. RESULT: The diagnosis of narcolepsy was confirmed by multiple sleep latency test along with human leukocyte antigen typing and cerebrospinal fluid hypocretin assay. CONCLUSION: The diagnosis of narcolepsy with cataplexy at onset can be challenging in young children. With more awareness of subtle signs such as cataplectic facies, earlier diagnosis is possible. To date, only 11 children between 6 and 18 years of age presenting with typical cataplectic facies have been reported in the literature. We present two patients, one of whom is the youngest individual (4 years old) yet described with the typical cataplectic facies.

The role of stress as a trigger for epileptic seizures: a narrative review of evidence from human and animal studies.

Stress is one of the most frequently self-identified seizure triggers in patients with epilepsy; however, most previous publications on stress and epilepsy have focused on the role of stress in the initial development of epilepsy. This narrative review explores the causal role of stress in triggering seizures in patients with existing epilepsy. Findings from human studies of psychological stress, as well as of physiologic stress responses in humans and animals, and evidence from nonpharmacologic interventions for epilepsy are considered. The evidence from human studies for stress as a trigger of epileptic seizures is inconclusive. Although retrospective self-report studies show that stress is the most common patient-perceived seizure precipitant, prospective studies have yielded mixed results and studies of life events suggest that stressful experiences only trigger seizures in certain individuals. There is limited evidence suggesting that autonomic arousal can precede seizures. Interventions designed to improve coping with stress reduce seizures in some individuals. Studies of physiologic stress using animal epilepsy models provide more convincing evidence. Exposure to exogenous and endogenous stress mediators has been found to increase epileptic activity in the brain and trigger overt seizures, especially after repeated exposure. In conclusion, stress is likely to exacerbate the susceptibility to epileptic seizures in a subgroup of individuals with epilepsy and may play a role in triggering "spontaneous" seizures. However, there is currently no strong evidence for a close link between stress and seizures in the majority of people with epilepsy, although animal research suggests that such links are likely. Further research is needed into the relationship between stress and seizures and into interventions designed to reduce perceived stress and improve quality of life with epilepsy.

The safety of UK video telemetry units: results of a national service evaluation.

PURPOSE: To assess patient safety during seizures occurring on UK video telemetry units and identify factors in unit infrastructure which may improve safety with the intention of producing national guidelines. METHODS: A prospective multicentre national service evaluation of the occurrence of adverse events and level of nurse attendance during seizures occurring on video telemetry units was performed. Data from 272 seizures from 27 video telemetry units across the UK were analysed. RESULTS: Adverse events occurred in 12% of seizures: 7% were physical events such as falls or respiratory compromise and 5% were unnoticed seizures. Nursing staff did not attend the patients in 44% of seizures and attendance was delayed beyond 30s in a further 29%. Only 27% of seizures were attended by a Healthcare Professional within half a minute. The most important factor shown to improve timely attendance of patients during seizures was the presence of a nurse dedicated to the telemetry bed(s). The site of the telemetry bed (bay or cubicle) and method of observation (direct or indirect) was less important. An optimal nurse-to-patient ratio was difficult to identify but the study suggests that a ratio of at least 1 nurse to 4 patients is appropriate. CONCLUSION: The results provide an evidence base for the production of national standards and guidelines for surveillance of patients during video telemetry to improve patient safety.

Comparison of heart rate variability parameters during complex partial seizures and psychogenic nonepileptic seizures.

PURPOSE: Psychogenic nonepileptic seizures (PNES) superficially resemble epileptic seizures. Little is known about ictal autonomic nervous system (ANS) activity changes in epilepsy and PNES. This study compares ictal heart rate variability (HRV) parameters as a reflection of ANS tone in epileptic seizures and PNES, and explores differences between interictal and ictal ANS tone in both patient groups. METHODS: Ictal HRV parameters were extracted from single-lead electrocardiography (ECG) data collected during video-electroencephalography (EEG) recordings of 26 patients with medically refractory temporal lobe epilepsy and 24 age- and sex-matched patients with PNES. One seizure per patient in a resting, wake, supine state was analyzed. Interictal ECG data were available for comparison from 14 patients in both groups. HRV parameters in time and frequency domains were analyzed (low frequency [LF], high frequency [HF], standard deviation of all consecutive normal R wave intervals [SDNN], square root of the mean of the sum of the squares of differences between adjacent normal R wave intervals [RMSSD]). CVI (cardiovagal index), CSI (cardiosympathetic index), and ApEn (approximate entropy) were calculated from Lorenz plots. KEY FINDINGS: There were significant differences between ictal HRV measures during epileptic and nonepileptic seizures in the time and frequency domains. CSI (p < 0.001) was higher in epileptic seizures. Time interval between two consecutive R waves in the ECG (RR interval) (p = 0.002), LF (p = 0.02), HF (p = 0.003), and RMSSD (p = 0.003) were significantly lower during epileptic seizures. Binary logistic regression yielded a significant model based on the differences in CSI classifying 88% of patients with epilepsy and 73% of patients with PNES correctly. The comparison between resting and ictal states in both seizure disorders revealed significant differences in RR interval (epilepsy p < 0.001, PNES p = 0.01), CSI (epilepsy p < 0.001, PNES p = 0.02), HF (epilepsy p = 0.002, PNES p = 0.03), and RMSSD (epilepsy p = 0.004, PNES p = 0.04). In patients with epilepsy there were also significant differences in ictal versus interictal mean values of ApEn (p = 0.03) and LF (p = 0.04). Although CSI was significantly higher, the other parameters were lower during the seizures. Stepwise binary regression in the 14 patients with epilepsy produced a significant model differentiating resting state from seizures in 100% of cases. The same statistical approach did not yield a significant model in the PNES group. SIGNIFICANCE: Our results show greater ANS activation in epileptic seizures than in PNES. The biggest ictal HRV changes associated with epileptic seizures (CSI, HF, and RMSSD) reflect high sympathetic system activation and reduced vagal tone. The reduced ApEn also reflects a high sympathetic tone. The observed ictal alterations of HRV patterns may be a more specific marker of epileptic seizures than heart rate changes alone. These altered HRV patterns could be used to detect seizures and also to differentiate epileptic seizures from PNES. Larger studies are justified with intergroup and intragroup comparisons between ictal and resting states.

Heart rate variability measures as biomarkers in patients with psychogenic nonepileptic seizures: potential and limitations.

Heart rate variability (HRV) metrics provide reliable information about the functioning of the autonomic nervous system (ANS) and have been discussed as biomarkers in anxiety and personality disorders. We wanted to explore the potential of various HRV metrics (VLF, LF, HF, SDNN, RMSSD, cardiovagal index, cardiosympathetic index, approximate entropy) as biomarkers in patients with psychogenic nonepileptic seizures (PNES). HRV parameters were extracted from 3-minute resting single-lead ECGs of 129 subjects (52 with PNES, 42 with refractory epilepsy and 35 age-matched healthy controls). Compared with healthy controls, both patient groups had reduced HRV (all measures P<0.03). Binary logistic regression analyses yielded significant models differentiating between healthy controls and patients with PNES or patients with epilepsy (correctly classifying 86.2 and 93.5% of cases, respectively), but not between patients with PNES and those with epilepsy. Interictal resting parasympathetic activity and sympathetic activity differ between healthy controls and patients with PNES or those with epilepsy. However, resting HRV measures do not differentiate between patients with PNES and those with epilepsy.

Ictal hiccup during absence seizure in a child.

Absence seizures are one of the features of idiopathic generalised epilepsy (IGE) and occur as component of many different syndromes. They are commonly associated with various clinical features such as mild clonic components, change in postural tone, automatisms and autonomic phenomena. Childhood absence epilepsy (CAE) is the prototype IGE with typical absence seizures. We report a child who had prominent ictal hiccups during an absence seizure, and discuss the possible mechanisms. [Published with video sequences].