Diagnostic Yield of Routine EEG in Adults with Active Epilepsy

Routine electroencephalogram (rEEG) is an important investigation in suspected seizures but can be normal in people with epilepsy. The diagnostic yield of rEEG varies considerably according to the patient group studied. We aimed to estimate the diagnostic yield of rEEG in a real-world cohort of adults with active epilepsy­a population not previously reported. This single centre study evaluated neurophysiology findings for adults with prolonged inpatient video EEG (vEEG)-confirmed active epilepsy, who had at least one prior rEEG. Sixty-eight patients had a total of 171 rEEGs, of which 93 (54.4%) were normal, 42 (24.6%) found non-specific abnormalities and 36 (21.1%) captured interictal epileptiform abnormalities (IIEAs). Serial rEEGs revealed a 22.1% yield of IIEAs on the first test, with the cumulative yield peaking at 33.8% on the fourth rEEG. This study adds to existing evidence regarding the limited diagnostic usefulness of serial rEEG in patients with active epilepsy.

Investment in epilepsy monitoring units improves epilepsy care-experience in a regional neuroscience centre.

An evaluation of the clinical yield of inpatient long-term video-EEG (vEEG) in a new epilepsy monitoring unit (EMU) was undertaken, with findings compared to the centre's prior method of bedside vEEG recording in a standard neurology ward, as reported in 2004. A retrospective analysis of neurophysiology reports for all adults who underwent elective vEEG monitoring in the EMU at Cork University Hospital between January 2015 and July 2016 was conducted. Of 115 vEEG studies in the EMU, 100 (87.0%) were deemed diagnostically conclusive, 14 (12.2%) failed to catch any clinical events and showed normal EEG throughout, and one (0.9%) captured spells of unclear clinical significance - the corresponding figures reported in 2004 for bedside vEEGs were 21.3%, 77% and 1.6%, respectively. The EMU offers a more effective method of recording inpatient vEEG, which aids decision-making and improves clinical outcomes. Some evidence-based measures which could further enhance diagnostic yield are discussed.

Foot Drop: Looking Beyond Common Peroneal Nerve Palsy: A Neurophysiology Centre Experience.

Foot drop is a complex symptom with a considerable range in aetiology, severity and prognosis. We aim to characterise the aetiologies of foot drop and assess the diagnostic contribution of neurophysiologic testing (NCS/EMG). Retrospective review of consecutive referrals of foot drop to the Neurophysiology Department in Cork University Hospital was performed over a two year period (January 2012 to December 2013). Of a total of 59 referrals, common peroneal nerve (CPN) palsy comprised only slightly more than half of cases; 3(5%) have central origin; 3(5%) have motor neuron disease. Six (10%) have diabetes; 7(12%) have cancer; 5(8%) were bilateral. NCS/EMG altered initial working diagnosis in 14 out of 52 (27%) cases whereby initial diagnosis was provided. However one-third of all cases revealed additional coexistent pathology in an anatomic location remote to that of the primary diagnosis. Foot drop with central and proximal localisations are important and under recognised. NCS/EMG is valuable and also reveals additional pathology which warrants investigation.

Utilization and Yield of Nerve Conduction Studies and Electromyography in Older Adults.

Older adults are at increased risk of both central and peripheral neurological disorders. Impaired nerve and muscle deficits contribute to morbidity and reduced quality of life. Our aim was to define the utilization and yield of nerve conduction studies (NCS) and electromyography (EMG) in older adults. We reviewed NCS and EMG records for all patients older than age 65 in the year 2012. Of 1,530 NCS and EMGs performed, 352 (23%) were in patients older than 65 (mean age 73.7, 52% male). 288 (83.7%) of NCS were abnormal as were 102 (71.8%) of EMGs. The likelihood of having an abnormal test result increased with increasing age. The most common diagnosis was peripheral neuropathy 231 (65.4%). The incidence of peripheral neuropathy is particularly high in this age group and detection is vital to prevent morbidity and improve quality of life.

Your diagnosis? Congenital foot drop.

A term infant was noted to have right-sided foot drop. We discuss the role of neurophysiology and diagnostic imaging.

Maternal and neonatal outcomes associated with gestational diabetes in women from culturally and linguistically diverse backgrounds in Western Australia.

AIMS: To compare maternal and neonatal outcomes for Australian-born women with gestational diabetes mellitus with those of culturally and linguistically diverse and non-culturally and linguistically diverse foreign-born women with gestational diabetes. METHODS: A total of 205,616 singleton births in Western Australia between 1998 and 2006 were examined using multivariate logistic regression. Risks of ten maternal and neonatal outcomes associated with gestational diabetes were compared for pregnancies with gestational diabetes to foreign-born women from both culturally and linguistically diverse and non-culturally and linguistically diverse backgrounds vs. Australian-born women. The same outcomes were also compared for pregnancies without gestational diabetes. RESULTS: Foreign-born culturally and linguistically diverse women were more likely to undergo emergency Caesarean section, but less likely to have pre-eclampsia, an elective Caesarean section or induced labour than Australian-born women. Their infants were less likely to be large for gestational age, require resuscitation or be transferred to specialist care. These differences were also evident among pregnancies without gestational diabetes to culturally and linguistically diverse women, but did not exist between foreign-born non-culturally and linguistically diverse women and Australian-born women with gestational diabetes. CONCLUSIONS: While gestational diabetes places women and infants at increased risk of adverse perinatal outcomes, these outcomes differed for foreign-born women from culturally and linguistically diverse backgrounds when compared with Australian-born women. Further investigation is required to elucidate why being foreign-born and culturally and linguistically diverse reduces the risk of several of these outcomes.

The heating of gas in a galaxy cluster by X-ray cavities and large-scale shock fronts.

Most of the baryons in galaxy clusters reside between the galaxies in a hot, tenuous gas. The densest gas in their centres should cool and accrete onto giant central galaxies at rates of 10-1,000 solar masses per year. No viable repository for this gas, such as clouds or new stars, has been found. New X-ray observations, however, have revealed far less cooling below X-ray temperatures than expected, altering the previously accepted picture of cooling flows. As a result, most of the gas must be heated to and maintained at temperatures above approximately 2 keV (ref. 3). The most promising heating mechanism is powerful radio jets emanating from supermassive black holes in the central galaxies of clusters. Here we report the discovery of giant cavities and shock fronts in a distant (z = 0.22) cluster caused by an interaction between a radio source and the hot gas surrounding it. The energy involved is approximately 6 x 10(61) erg, the most powerful radio outburst known. This is enough energy to quench a cooling flow for several Gyr, and to provide approximately 1/3 keV per particle of heat to the surrounding cluster.

EEG use in a tertiary referral centre.

The aim of this study was to retrospectively audit all electroencephalograms (EEGs) done over a 2-month period in 2009 by the Neurophysiology Department at Cork University Hospital. There were 316 EEGs performed in total, of which 176/316 (56%) were done within 24 hours of request. Out of 316 EEGs, 208 (66%) were considered 'appropriate' by SIGN and NICE guidelines; 79/208 (38%) had abnormal EEGs and 28 of these abnormal EEGs had epileptiform features. There were 108/316 (34%) 'inappropriate' requests for EEG; of these 15/108 (14%) were abnormal. Of the 67/316 (21%) patients who had EEGs requested based on a history of syncope/funny turns: none of these patients had epileptiform abnormalities on their EEGs. Our audit demonstrates that EEGs are inappropriately over-requested in our institution in particular for cases with reported 'funny turns' and syncope. The yield from EEGs in this cohort of patients was low as would be expected.

A review of nerve conduction studies in cases of suspected compression neuropathies of the upper limb.

INTRODUCTION: Entrapment neuropathies, particularly those affecting upper limbs, are common reasons for referral for nerve conduction studies (NCS). However, concordance between clinical findings and NCS findings, especially in patients being considered for intervention including decompressive surgery, has not been assessed. METHODS: We conducted a retrospective study using records from a tertiary referral centre's neurophysiology database. We aimed to establish the proportions of agreement between the suspected clinical diagnosis as defined by the referring clinician and NCS findings in the setting of an upper limb entrapment neuropathy. RESULTS: Of the 571 referrals for NCS, suspected bilateral carpal tunnel syndrome was the commonest reason for referral (30.5%). In total, there was 51.5% concordance between suspected clinical diagnosis and NCS findings. Patients with NCS evidence of an entrapment neuropathy (n = 437) were more likely to be older compared to those with normal studies (54.0 +/- 15.6 years vs. 45.9 +/- 13.4 years, p < 0.001). Those with normal NCS findings were more likely to be female (72%, p = 0.001). An alternative or additional diagnosis was found in 14%. CONCLUSION: This study raises concerns regarding the appropriateness of referral for decompressive surgery based on clinical diagnosis alone as many have an additional or alternative diagnosis as suggested by NCS findings.

Identifying young Aboriginal and Torres Strait Islander children in linked administrative data: A comparison of methods.

BACKGROUND: In the ongoing debate on optimum methods for identification of Indigenous people within linked administrative data, few studies have examined the impacts of method on population counts and outcomes in family-based linkage studies of Aboriginal children. OBJECTIVE: To quantify differences between three algorithms in ascertaining Aboriginal and Torres Strait Islander children in linked administrative data. METHODS: Linked administrative health data for children born in Western Australia (WA) from 2000-2013, were used to examine the cohorts identified by three methods: A) the Indigenous Status Flag (ISF, derived by the WA Data Linkage Branch using a multistage-median approach) for the children alone; B) the ISF of the children, their parents and grandparents; and C) Indigenous status of the child, mother or father on either of the child's perinatal records (Midwives or birth registration), to determine differing characteristics of each cohort. RESULTS: Method B established a larger cohort (33,489) than Method C (33,306) and Method A (27,279), with all methods identifying a core group of 26,790 children (80-98%). Compared with children identified by Method A, additional children identified by Methods B or C, were from less-disadvantaged and more urban areas, and had better perinatal outcomes (e.g. lower proportions of small-for-gestational age, 10% vs 16%). Differences in demographics and health outcomes between Methods C and B were minimal. CONCLUSIONS: Demographic and perinatal health characteristics differ by Aboriginal identification method. Using perinatal records or the ISF of parents and grandparents (in addition to the ISF of the child) appear to be more inclusive methods for identifying young Indigenous children in administrative datasets. KEYWORDS: Aboriginal health, identification, data linkage, Indigenous, child, methodology.

A review of neurological abnormalities associated with the practise of music.

A number of neurological abnormalities associated with the playing of musical instruments have been described which can cause great difficulty for performers. However, there has been no attempt to consider this in an Irish context, a cultural setting which encompasses an unusual range of playing styles and musical instruments. We performed a retrospective assessment of musicians referred to our service for neurophysiological testing. In this series of 17 musicians, most (59%) had more than one abnormality on testing. We discovered fifteen cases of carpal tunnel syndrome, eleven cases of ulnar neuropathy, and four cases of focal dystonia. Compared to previously published reports, our series contains a greater proportion of amateur musicians, a group not well studied in the literature.

An audit of traumatic nerve injury.

The impact of trauma in the Irish healthcare setting is considerable. We present the results of a retrospective assessment of referrals to a Neurophysiology department for suspected traumatic nerve injury. A broad range of traumatic neuropathies was demonstrated on testing, from numerous causes. We demonstrate an increased liklihood of traumatic nerve injury after fracture / dislocation (p = 0.007). Our series demonstrates the need for clinicians to be aware of the possibility of nerve injury post trauma, especially after bony injury.

How to work up a patient with polyneuropathy?

Undiagnosed and untreated neuropathy may lead to disability and poor quality of life. Ordering every possible test to find the cause of polyneuropathy can waste time and resources. In this study, we investigated what could be used as a routine neuropathy screen. A retrospective audit of all charts of patients diagnosed to have polyneuropathy by nerve conduction studies from November 2001 to November 2002 were carried out. Demographics, background history, type of neuropathy and investigations done were documented. The charts of 61 patients were audited. 12 patients had a background history of diabetes mellitus. 2 patients had history of alcohol abuse. 23 patients presented with paraesthesia and 33 with weakness of limbs. We found a cause of polyneuropathy in 79% of cases. In most patients with polyneuropathy where a cause can be identified, this can be achieved by the medical history, neurological examination, nerve conduction studies and the baseline blood tests. We suggest a 3-step approach to the diagnostic workup of polyneuropathy.

Can state or response entropy be used as a measure of sleep depth?

SUMMARY: In this prospective observational study we examined the potential of the spectral entropy measures 'state' and 'response' entropy (Entropy monitor), as measures of sleep depth in 12 healthy adult subjects. Both median state and response entropy values varied significantly with sleep stage (p = 0.017 and p = 0.014 respectively; ANOVA). Median state or response entropy did not decrease significantly during the transition from awake to stage I sleep (p > 0.017). State entropy values decreased significantly between sleep stages I and II (p < 0.001). Both state and response entropy values were significantly less (40 and 45 arbitrary units respectively) in stage III (slow wave sleep) vs stage II sleep (p = 0.008). We conclude that state and response entropy values, when expressed as a function of time, may be a useful means of quantifying aspects of sleep.

Aetiology and prognosis of encephalopathic patterns on electroencephalogram in a general hospital.

The purpose of this study was to investigate the frequency and clinical outcome of patients with encephalopathic electroencephalograms (EEGs) in a neurophysiology department based in a general hospital. We performed a retrospective review of all EEGs obtained during an 18-month period in a large tertiary referral hospital. The referral reasons for EEG, the diagnoses reached, and patient outcomes were reviewed according to EEG severity. One hundred and twenty-three patients with encephalopathic EEGs were reviewed. The most common referral reason found was for an assessment of a possible first-onset seizure. The most common diagnosis found was one of dementia or learning disability. Of patients who were followed-up for a median of 19 months, 20.7% had died. The mortality rate generally increased according to the severity of the encephalopathy on EEG. However, 21.4% of those patients with excessive theta activity only on EEG had died. This study highlights an increased mortality even in the apparently 'milder' degrees of EEG abnormalities.

Translocated EspF protein from enteropathogenic Escherichia coli disrupts host intestinal barrier function.

The mechanisms by which enteropathogenic Escherichia coli (EPEC), an important cause of diarrhea among infants in developing countries, induce symptoms are not defined. EPEC have a type III secretion system required for characteristic attaching and effacing changes that modify the cytoskeleton and apical surface of host cells. Infection of polarized intestinal epithelial cell monolayers by EPEC leads to a loss of transepithelial electrical resistance, which also requires the type III secretion system. We demonstrate here that EspF, a protein that is secreted by EPEC via the type III secretion system, is not required for quantitatively and qualitatively typical attaching and effacing lesion formation in intestinal epithelial cells. However, EspF is required in a dose-dependent fashion for the loss of transepithelial electrical resistance, for increased monolayer permeability, and for redistribution of the tight junction-associated protein occludin. Furthermore, the analysis of EPEC strains expressing EspF-adenylate cyclase fusion proteins indicates that EspF is translocated via the type III secretion system to the cytoplasm of host cells, a result confirmed by immunofluorescence microscopy. These studies suggest a novel role for EspF as an effector protein that disrupts intestinal barrier function without involvement in attaching and effacing lesion formation.

Non-traumatic brachial plexopathies, clinical, radiological and neurophysiological findings from a tertiary centre.

OBJECTIVE: To establish the clinical characteristics, aetiology, neuro-physiological characteristics, imaging findings and other investigations in a cohort of patients with non-traumatic brachial plexopathy (BP). METHODS: A 3-year retrospective study of patients with non-traumatic BP identified by electromyography (EMG) and nerve conduction studies (NCS). Clinical information was retrieved from patients' medical charts. RESULTS: Twenty-five patients were identified. Causes of BP included neuralgic amyotrophy (NA) (48%), neoplastic (16%), radiation (8%), post infectious (12%), obstetric (4%), rucksack injury (4%), thoracic outlet syndrome (4%) and iatrogenic (4%). Patients with NA presented acutely in 50%. The onset was subacute in all others. Outcome was better for patients with NA. All patients with neoplastic disease had a previous history of cancer. MRI was abnormal in 3/16 patients (18.8%). PET scanning diagnosed metastatic plexopathy in two cases. CONCLUSIONS: NA was the most common cause of BP in our cohort and was associated with a more favourable outcome. The authors note potentially discriminating clinical characteristics in our population that aid in the assessment of patients with brachial plexopathies. We advise NCS and EMG be performed in all patients with suspected plexopathy. Imaging studies are useful in selected patients.

A study of idiopathic generalised epilepsy in an Irish population.

UNLABELLED: Idiopathic generalised epilepsy (IGE) is subdivided into syndromes based on clinical and EEG features. PURPOSE: The aim of this study was to characterise all cases of IGE with supportive EEG abnormalities in terms of gender differences, seizure types reported, IGE syndromes, family history of epilepsy and EEG findings. We also calculated the limited duration prevalence of IGE in our cohort. METHODS: Data on abnormal EEGs were collected retrospectively from two EEG databases at two tertiary referral centres for neurology. Clinical information was obtained from EEG request forms, standardised EEG questionnaires and medical notes of patients. RESULTS: two hundred twenty-three patients met our inclusion criteria, 89 (39.9%) male and 134 (60.1%) females. Tonic clonic seizures were the most common seizure type reported, 162 (72.65%) having a generalised tonic clonic seizure (GTCS) at some time. IGE with GTCS only (EGTCSA) was the most common syndrome in our cohort being present in 94 patients (34 male, 60 female), with 42 (15 male, 27 female) patients diagnosed with Juvenile myoclonic epilepsy (JME), 23 (9 male, 14 female) with Juvenile absence epilepsy (JAE) and 20 (9 male, 11 female) with childhood absence epilepsy (CAE). EEG studies in all patients showed generalised epileptiform activity. CONCLUSIONS: More women than men were diagnosed with generalised epilepsy. Tonic clonic seizures were the most common seizure type reported. EGTCSA was the most frequent syndrome seen. Gender differences were evident for JAE and JME as previously reported and for EGTCSA, which was not reported to date, and reached statistical significance for EGTCA and JME.

How well is peripheral neuropathy investigated? An audit from a regional neurophysiology department.

BACKGROUND: Peripheral neuropathy (PN) is common and increases with age. AIM: To assess how patients with confirmed peripheral neuropathy on nerve conduction studies (NCS) were investigated and to determine whether there was any difference in investigation based on patient age or referral source. DESIGN: Retrospective audit. METHODS: All EMG/NCS reports from a one-year period were analysed. The computer laboratory system was used to determine which blood tests had been performed on those patients with confirmed peripheral neuropathy on NCS. RESULTS: Over 50% of patients referred from within the hospital did not have a basic blood screen to search for the aetiology. There was no significant difference in investigation practise based on patient age or referral source. CONCLUSION: Our results highlight the lack of systematic investigation in a university teaching hospital. As a result of this audit, a protocol has been prepared and is distributed with NCS/EMG reports.

The effect of hypocholesterolemic drug treatment on adrenocortical cell function.

The role of exogenous lipoprotein cholesterol versus endogenous cholesteryl esters as substrates in adrenal steroidogenesis was studied in isolated rat adrenal cells. Hypocholesterolemic drugs were used in rats to depress the plasma cholesterol concentration and the adrenal cholesterol concentration. Adrenal cortical cells were prepared in the usual way. The steroidogenic response to ACTH in normal adrenal cells and in cells which have been cholesterol-depleted was studied. Normal adrenal cells responded specifically over a 6 h incubation period to low doses of ACTH (half-maximal response equivalent to 40 microunits ACTH). These normal cells exhibited no altered response over a 3 h period to ACTH in the presence of serum or serum lipoproteins. The hypocholesterolemic drugs, 4-aminopyrazolo-[3,4-d]-pyrimidine, hexestrol and 17 alpha-ethinyl estradiol were used to lower plasma cholesterol, and after 1 day of 4-aminopyrazolo-[3,4-d]-pyrimidine and 5 days of hexestrol or 17 alpha-ethinyl estradiol treatment the plasma total cholesterol concentrations were similar. After 3 days of 4-aminopyrazolo-[3,4-d]-pyrimidine treatment the adrenal total cholesterol content was lower than after 1 day of this treatment, or 5 days of hexestrol treatment or 5 days of 17 alpha-ethinyl extradiol treatment. Lipoproteins had no significant effect on ACTH-stimulated steroidogenesis in cells isolated from rats treated for 1 day with 4-aminopyrazolo-[3,4-d]-pyrimidine, or for 5 days with hexestrol or 17 alpha-ethinyl estradiol. However, lipoproteins did stimulate steroidogenesis in cells from rats treated for 3 days with 4-aminopyrazolo-[3,4-d]-pyrimidine. The results show that normal adrenal cells contain a reserve of intracellular cholesterol so that the supply of endogenous cholesterol for steroidogenesis does not limit the response to ACTH and exogenous lipoproteins have no effect on steroidogenesis. However, if the cells are severely depleted of cholesterol then exogenous lipoproteins must be added for maximal steroidogenesis to occur.