OBJECTIVE: To follow the clinical course of patients with the mitochondrial DNA mutation 3243A>G for 3 years. METHODS: Thirty-three adult patients with the 3243A>G mutation entered a 3-year follow-up study. They were clinically evaluated annually, audiometry was performed, and samples were drawn for the analysis of blood chemistry and mutation heteroplasmy in leukocytes. Holter recording was performed three times during the follow-up and echocardiography, neuropsychological assessment, and quantitative EEG and brain imaging conducted at entry and after 3 years. RESULTS: The incidence of new neurologic events was low during the 3-year follow-up. Sensorineural hearing impairment (SNHI) progressed, left ventricular wall thickness increased, mean alpha frequency in the occipital and parietal regions decreased, and the severity of disease index (modified Rankin score) progressed significantly. The rate of SNHI progression correlated with mutation heteroplasmy in muscle. The increase in left ventricular wall thickness was seen almost exclusively in diabetic patients. Seven patients died during the follow-up, and they were generally more severely affected than those who survived. CONCLUSIONS: Significant changes in the severity of disease, sensorineural hearing impairment, left ventricular hypertrophy, and quantitative EEG were seen in adult patients with 3243A>G during the 3-year follow-up.
Comment In: Neurology. 2007 Jan 9;68(2):163-417210904
Hepatic encephalopathy (HE) is a severe and frequent complication of liver cirrhosis characterized by abnormal cerebral function. Little is known about the underlying neural mechanisms in HE and human data are sparse. Electrophysiological methods such as evoked brain potentials after somatic stimuli can be combined with inverse modeling of the underlying brain activity. Thereby, information on neuronal dynamics and brain activity can be studied in vivo. The aim of this study was to investigate the sensory brain processing in patients with HE.
Twelve patients with minimal or overt HE and 26 healthy volunteers were included in the study. Cerebral sensory processing was investigated as (i) an auditory reaction time task; (ii) visual and somatosensory evoked brain potentials, and (iii) reconstruction of the underlying brain activity.
Somatosensory evoked potentials were reproducible (all P>0.05), whereas flash evoked potentials were not reproducible (all P
The long QT syndrome (LQTS) is an inherited cardiac channelopathy associated with syncope and sudden cardiac death due to ventricular arrhythmias. It is most frequently caused by potassium channel mutations. Potassium channels are also expressed in brain tissue and play an important role in idiopathic epilepsies. Recent reports have indicated that related potassium channel mutations may coexpress as concomitant epilepsy and LQTS.
The purpose of this study was to explore cerebral activity by means of EEG recordings in individuals with LQTS related to potassium channel mutations.
Seventeen individuals with confirmed LQTS related to potassium channel mutations (11 LQT1 and 6 LQT2) were prospectively studied with 21-channel electroencephalography (EEG) LQTS -related symptoms, comorbidity, medication, and QTc (12-lead ECG) were recorded. Sixteen healthy individuals previously studied with EEG served as a control group. All EEGs were reviewed by two independent neurophysiologists.
EEG recordings were abnormal in 12 of 17 patients (71%) in the LQTS group, whereas abnormalities were present in only 2 of 16 healthy controls (13%; P
OBJECTIVE: To determine whether the somatosensory pathways are involved or not in konzo. METHODS: In 1998, 21 konzo subjects (15 females and 6 males; mean age 21 years) underwent a SEP study with a two-channel-equipment (Medtronic Keypoint, Denmark) whereas in 2000, 15 subjects (7 females and 8 males; mean age 21 years) participated in a study with a 4-channel-equipment. RESULTS: Most subjects (19/21 in 1998 and 12/15 in 2000) showed normal median SEPs. The remainders had no median cortical responses. All 21 subjects in 1998 and 9 out of 15 in 2000 showed abnormalities of tibial SEPs mainly consisting of absence of cortical responses, prolonged cortical latencies, and central sensory delay to the lumbar spine. Most subjects showed normal absolute latencies both at peripheral and spinal levels. The SEP findings did not correlate with the severity, neither the duration of konzo, nor the experience or not of sensory symptoms at the onset of the disease. CONCLUSION: Our findings are not specific of konzo. However, they suggest involvement of intracranial somatosensory pathways and point to similarities with other motor neuron diseases.
OBJECT: The authors prospectively studied the occurrence of clinical and nonclinical electroencephalographically verified seizures during treatment with an intracranial pressure (ICP)-targeted protocol in patients with traumatic brain injury (TBI). METHODS: All patients treated for TBI at the Department of Neurosurgery, University Hospital Umeå, Sweden, were eligible for the study. The inclusion was consecutive and based on the availability of the electroencephalographic (EEG) monitoring equipment. Patients were included irrespective of pupil size, pupil reaction, or level of consciousness as long as their first measured cerebral perfusion pressure was > 10 mm Hg. The patients were treated in a protocol-guided manner with an ICP-targeted treatment based on the Lund concept. The patients were continuously sedated with midazolam, fentanyl, propofol, or thiopental, or combinations thereof. Five-lead continuous EEG monitoring was performed with the electrodes at F3, F4, P3, P4, and a midline reference. Sensitivity was set at 100 muV per cm and filter settings 0.5-70 Hz. Amplitude-integrated EEG recording and relative band power trends were displayed. The trends were analyzed offline by trained clinical neurophysiologists. RESULTS: Forty-seven patients (mean age 40 years) were studied. Their median Glasgow Coma Scale score at the time of sedation and intubation was 6 (range 3-15). In 8.5% of the patients clinical seizures were observed before sedation and intubation. Continuous EEG monitoring was performed for a total of 7334 hours. During this time neither EEG nor clinical seizures were observed. CONCLUSIONS: Our protocol-guided ICP targeted treatment seems to protect patients with severe TBI from clinical and subclinical seizures and thus reduces the risk of secondary brain injury.
Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, McMaster University Medical Centre, 1200 Main Street West, HSC-2C, Hamilton, Ontario, Canada L8N 3Z5; Programs for Assessment of Technology in Health (PATH) Research Institute, St. Joseph's Healthcare Hamilton, 2000-25 Main Street West, Hamilton, Ontario, Canada L8P 1H1. Electronic address: email@example.com.
A systems analysis perspective was undertaken to evaluate access to surgery for children with medically refractory epilepsy (MRE) in Ontario, the largest province in Canada. The analysis focused on the assessment of referral patterns, healthcare utilization, time intervals and patient flow to determine surgical candidacy in children with MRE. The purpose of this systems analysis study was to identify rate limiting steps that may lead to delayed surgical candidacy decision and surgery.
Prolonged video electroencephalography (vEEG) is the common entry point into the process for all potential epilepsy surgery candidates. Therefore, a single centre retrospective chart review of children and adolescents referred to the epilepsy monitoring unit (EMU) for vEEG monitoring at the primary referral centre for paediatric epilepsy surgery in the province. Basic demographic and referral data were abstracted for all screened cases. Included cases were: (1) age 8h). Forty five percent (n=160) of patients came to seizure conference for discussion of their data, of whom 40% (64/160) were considered surgical candidates. Time from first seizure to EMU referral was approximately 4.6 years. Time from referral to admission and admission to first seizure conference were approximately 103 days and 71 days, respectively. From initial EMU referral to surgery ranged from 1.6 to 1.1 years depending on whether the patient required invasive monitoring with intracranial EEG. Overall, 95% of surgical patients had a reduction in seizure frequency, 74% were seizure free after one year post-surgery.
Referral rates for surgical assessment are low relative to the estimated number of children living with MRE in Ontario, less than 2%. Hence, only a limited number of children with this disorder in the province of Ontario who could benefit from epilepsy surgery are being assessed for surgical candidacy. The majority of Ontario children with MRE are not being provided the potential opportunity to be seizure free and live without functional limitations following surgical intervention. These data document the critical need for health system redesign in Ontario, the goal of which should be to provide more consistent and just access to evidence-based medical and surgical care for those citizens of the province who suffer from epilepsy.
OBJECTIVES: To determine if young adults with a history of typical absence epilepsy (AE) in childhood have a greater risk of accidental injury than controls with juvenile rheumatoid arthritis (JRA). To assess the nature and severity of these injuries. METHODS: All patients with AE or JRA diagnosed between 1977 and 1985, who were 18 years or older at the onset of the study, were identified from review of pediatric electroencephalographic records for the province of Nova Scotia (AE) or review of the medical records database at the only tertiary care pediatric center for the province (JRA). Fifty-nine (86%) of 69 patients with AE and 61 (80%) of 76 patients with JRA participated in an interview in 1994 or 1995, assessing nature, severity, and treatment of prior accidental injuries. Patients with AE were further questioned about injuries sustained during an absence seizure. RESULTS: Sixteen (27%) of 59 patients with AE reported accidental injury during an absence seizure, with risk of injury being 9% per person-year of AE. Most injuries (81%) occurred during anti-epileptic drug therapy. Although the majority of injuries did not require treatment, 2 (13%) of 16 patients required minor treatment and 2 (13%) of 16 were admitted to hospital. The risk of accidental injury resulting from an absence seizure in person-years at risk was highest in juvenile myoclonic epilepsy (45%), moderate in juvenile AE (14%), and lowest in childhood AE (3%). Patients with AE had a greater number of overall accidental injuries than those with JRA (P
Department of Clinical Neurosciences, University of Calgary, 1403 29 Street NW, Calgary, Alberta, T2N2T9, Canada; Hotchkiss Brain Institute, University of Calgary, 1403 29 Street NW, Calgary, Alberta, T2N2T9, Canada.
The Canadian Appropriateness of Epilepsy Surgery (CASES) tool was developed to help physicians identify patients who should be referred for an epilepsy surgery evaluation. The aim of this study was to determine the accuracy of this tool using a population-based cohort registry (the Swedish National Epilepsy Surgery Register) of patients who underwent epilepsy surgery between 1990 and 2012.
Overall, 1044 patients met eligibility criteria for the study and were deemed to be surgical candidates by epilepsy experts. Demographic and epilepsy related characteristics were examined and summarized using descriptive statistics. A CASES appropriateness score was calculated for each of these patients. Chi squared analyses or fisher's exact tests were used to determine if there were any relationships between demographic and epilepsy related characteristics not captured in the tool and appropriateness scores.
The mean appropriateness score was 8.6 and 985 (Sensitivity: 94.35%; 95% CI, 92.77%-95.60%) patients were appropriate, 46 (4.41%; 95% CI, 3.31%-5.84%) were uncertain, and 13 (1.25%; 95% CI, 0.72%-2.13%) were inappropriate for an epilepsy surgery evaluation. The mean necessity score, which was only calculated for the 985 appropriate patients, was 8.7. All 13 inappropriate patients had tried less than two anti-epileptic drugs (AEDs). In addition, age at onset of epilepsy and age at epilepsy surgery were both significantly associated with appropriateness score.
These results demonstrate that the CASES tool is highly sensitive as it designated 94.3% of epilepsy surgery patients as appropriate for an epilepsy surgery evaluation. All of those classified as inappropriate were not drug resistant, as they had not yet tried two AEDs.
Two large prospective cohort studies of childhood epilepsy (Nova Scotia and the Netherlands) each developed a statistical model to predict long-term outcome. We sought to evaluate the accuracy of a prognostic model based on the two studies combined.
Analyses with classification tree models and stepwise logistic regression produced predictive models for the combined dataset and the two separate cohorts. The resulting models were then externally validated on the opposite cohort. Remission was defined as no longer receiving daily medication for any length of time at the end of follow-up.
The combined cohorts yielded 1,055 evaluable patients. At the end of follow-up (>or=5 years in >96%), 622 (59%) were in remission. By using the combined data, the classification tree model and the logistic regression model predicted the outcome correctly in approximately 70%. The classification tree model split the data on epilepsy type and age at first seizure. Predictors in the logistic regression model were: seizure number before treatment, age at first seizure, absence seizures, epilepsy types of symptomatic generalized and symptomatic partial, preexisting neurologic signs, intelligence, and the combination of febrile seizures and cryptogenic partial epilepsy. When the prediction models from each cohort were cross-validated on the opposite cohort, the outcome was predicted slightly less accurately than did the model from the combined data.
Based on currently available clinical and EEG variables, predicting the outcome of childhood epilepsy may be difficult and appears to be incorrect in about one of every three patients.