PubMed Health⌕ Search

Biomedical subjects

M R Newton

Publications and source records attributed to M R Newton.

At least 19 recordsLinked to original sources
PubMed2003

Idiopathic generalised epilepsy of adult onset: clinical syndromes and genetics.

OBJECTIVE: To study the clinical features and genetics of idiopathic generalised epilepsy (IGE) beginning in adult life. METHODS: Consecutive patients with IGE, defined as generalised seizures with spike or polyspike and wave on EEG, were studied in the setting of a first seizure clinic where an early postictal EEG record is part of the protocol. Patients were divided into two groups: "classical IGE" with onset before 20 years and inclusive of all the IGE subsyndromes recognised by the international classification; and "adult onset IGE", when seizure onset was at age 20 years or later. Seizure patterns, clinical features, and genetics of the adult onset group were examined. RESULTS: Of 121 patients with an electro-clinical diagnosis of IGE, 34 (28%) were diagnosed as adult onset IGE. The seizure patterns in these 34 cases were tonic-clonic seizures + absences (3), tonic-clonic seizures + myoclonus (6), and tonic-clonic seizures alone (25). Tonic-clonic seizures were often precipitated by alcohol or sleep deprivation. The proportion of affected first and second degree relatives did not differ between the classical and adult onset IGE groups. Twenty adult onset cases were treated with sodium valproate, four with other antiepileptic drugs, and 10 were untreated. Follow up of 32 of the 34 cases (for 31 (22) months (mean (SD)) showed that tonic-clonic seizures recurred in eight patients: five with identified provocative factors and three without. CONCLUSIONS: Adult onset IGE is a relatively frequent and benign disorder. Seizures are usually provoked and are easy to control. Patients in this age group may often be misdiagnosed as having non-lesional partial epilepsy. Early postictal EEG and sleep deprivation studies may improve the detection of these patients. Pedigree analysis suggests that adult onset IGE, like classical IGE, has a genetic aetiology.

Adolescent↗
PubMed2001

Prolonged cortical silent period after transcranial magnetic stimulation in generalized epilepsy.

Transcranial magnetic stimulation (TMS) produces a cortical silent period (CSP) during a voluntary contraction. The duration of the CSP was used to assess the level of intracortical inhibition in patients with untreated idiopathic generalized epilepsy (IGE). Mean CSP duration was assessed at three TMS stimuli in 21 patients with IGE compared with 19 normal control subjects. Mean CSP duration was increased at all stimulus intensities, indicating that intracortical inhibition is increased in patients with IGE.

Adolescent↗
PubMed2001

Hippocampal sclerosis following brief generalized seizures in adulthood.

This report describes a patient who had a first generalized tonic clonic seizure (GTCS) at the age of 18 years. The initial MRI scan was normal on visual and quantitative examination. After a further six GTCS, a second MRI scan showed reduced hippocampal volume and increased hippocampal T2 signal, which was confirmed in a third scan. Therefore, hippocampal sclerosis may be acquired in adulthood after brief GTCS.

Adolescent↗
PubMed2001

Nonenhanced limited CT in children suspected of having appendicitis: prospective comparison of attending and resident interpretations.

PURPOSE: To prospectively compare resident and attending radiologic interpretations of nonenhanced limited computed tomographic (CT) scans obtained in children suspected of having appendicitis. MATERIALS AND METHODS: Seventy-five consecutive children underwent nonenhanced limited CT for suspected appendicitis. The scans were prospectively interpreted by a resident and an attending radiologist, each unaware of the other's interpretation. The probability that the findings indicated a diagnosis of appendicitis, level of certainty in the interpretation, and presence of an alternate diagnosis were statistically analyzed. RESULTS: Nineteen children (25%) had appendicitis. The area under the receiver operating characteristic curve was not significantly different between residents (0.97 +/- 0.02) and attendings (0.95 +/- 0.04). The percentage agreement between residents and attendings was 91% (kappa = 0.73 +/- 0.095). The average level of certainty tended to be higher for attendings (93% +/- 15) than residents (89% +/- 12). The sensitivity, specificity, and accuracy of resident interpretations were 63%, 96%, and 88%, respectively, compared with those of attending interpretations--95%, 98%, and 97%, respectively. Residents and attendings noted alternate diagnoses in 30% of children without appendicitis. CONCLUSION: A high level of agreement exists between resident and attending radiologists in the interpretation of nonenhanced limited CT scans in children suspected of having appendicitis. Residents, however, tend to be less confident in their interpretations.

Adolescent↗
PubMed2000

Ictal SPECT and interictal PET in the localization of occipital lobe epilepsy.

PURPOSE: To compare the localizing value of ictal single photon emission computed tomography (SPECT) and interictal fluorodeoxyglucose-positron emission tomography (FDG-PET) in refractory occipital lobe epilepsy. METHODS: Six patients who underwent surgery for refractory epilepsy associated with pathology in the occipital lobe were retrospectively selected from records of the Austin & Repatriation Centre Comprehensive Epilepsy Programme. Interictal SPECT and PET and ictal SPECT were obtained by standard methods. All studies were read by a nuclear medicine expert blinded to clinical data except the diagnosis of epilepsy. RESULTS: Ictal SPECT showed unilateral occipital hyperperfusion in five of six cases often accompanied by temporal lobe hyperperfusion. These patterns were seen in cases with or without magnetic resonance imaging (MRI) abnormality. Interictal SPECT was not localizing in any case, in contrast to PET, which showed occipital hypometabolism in three of five studies. CONCLUSIONS: Ictal SPECT can provide novel localizing data in MRI-negative occipital lobe epilepsy. Interictal PET can provide useful localizing information, but its role in providing novel information was not demonstrated. Interictal SPECT is useful only as a baseline to aid in interpretation of ictal studies.

Adult↗
PubMed1999

Benign partial seizures of adolescence.

PURPOSE: A benign syndrome of partial seizures in adolescents (BPSA) was described by Loiseau et al. in 1978, but confirmation of this syndrome has been lacking. We sought to identify BPSA among teenagers with new-onset focal seizures enrolled in our prospective first-seizure study and to assess the EEG and magnetic resonance imaging (MRI) findings. METHODS: We searched the study database for patients aged between 10 and 20 years with focal seizures who did not have idiopathic partial epilepsies, epileptogenic lesions on MRI, or recurrent tonic-clonic seizures during 2 years of follow-up. RESULTS: The database contained 92 adolescents, including 37 with partial epilepsy, of whom eight (22%) patients matched the description of BPSA. All eight patients had seizures with a sensory/motor "march." Six had a secondarily generalized seizure and two had simple partial seizures alone. Epileptiform abnormalities were documented in five cases but lacked a distinctive morphology or distribution. No lesions were seen on MRI. CONCLUSIONS: BPSA can be provisionally diagnosed in teenagers with unprovoked focal seizures characterized by a march of sensory/motor symptoms, whose MRI is normal. The psychosocial consequences of chronic epilepsy in adolescence are considerable, so early recognition of this benign syndrome is important.

Adolescent↗
PubMed1998

Epileptology of the first-seizure presentation: a clinical, electroencephalographic, and magnetic resonance imaging study of 300 consecutive patients.

BACKGROUND: Prognosis and treatment of the first seizure depends on identification of a specific epilepsy syndrome, yet patients with first seizures are generally regarded as a homogeneous group. We studied whether it is possible to diagnose specific epilepsy syndromes promptly by use of standard clinical methods, electroencephalography (EEG) and magnetic resonance imaging (MRI). METHODS: 300 consecutive adults and children presented with unexplained seizures. We systematically collected clinical data from patients and witnesses, and attempted to obtain an EEG within 24 h of the seizure. Where the EEG was negative, a sleep-deprived EEG was done. MRI was done electively. FINDINGS: A generalised or partial epilepsy syndrome was clinically diagnosed in 141 (47%) patients. Subsequent analysis showed that only three of these clinical diagnoses were incorrect. Addition of the EEG data enabled us to diagnose an epilepsy syndrome in 232 (77%) patients. EEG within 24 h was more useful in diagnosis of epileptiform abnormalities than later EEG (51 vs 34%). Neuroimaging showed 38 epileptogenic lesions, including 17 tumours. There were no lesions in patients for whom generalised epilepsy was confirmed by EEG. Our final diagnoses were: generalised epilepsy (23% of patients); partial epilepsy (58%); and unclassified (19%). INTERPRETATION: An epilepsy syndrome can be diagnosed in most first-seizure patients. Ideally, an EEG should be obtained within 24 h of the seizure followed by a sleep deprived EEG if necessary. MRI aids diagnosis and should be done for all patients except for those with idiopathic generalised epilepsies and for children with benign rolandic epilepsy.

Adolescent↗
PubMed1997

Cytokine gene expression in pancreatic islet grafts in the rat.

We examined the production of cytokine message in allogeneic and syngeneic rat pancreatic islet grafts using specific primers and polymerase chain reaction. Freshly isolated islet preparations contained transcripts for interleukin (IL)-1alpha, IL-6, IL-10, and interferon-gamma (IFN-gamma) but not for IL-2. IL-1alpha in allogeneic grafts showed increased and consistently high expression from 1 to 7 days after transplantation, but the level in syngeneic grafts fell quickly to pretransplant levels. IL-2 and IFN-gamma transcripts were found in allogeneic grafts at 1, 3, 5, and 7 days after transplantation with a peak at day 5, but these cytokines were almost absent from syngeneic grafts. The peak of IL-6 expression was 1 day after transplantation in both syngeneic and allogeneic grafts, and then the level fell quickly. IL-10 was produced at approximately the same high level at all time points in both syngeneic and allogeneic grafts. The results show that freshly isolated islet preparations contain IL-1alpha, IL-6, IL-10, and IFN-gamma transcripts at the time of transplantation. The initial production of cytokines in islet grafts, especially IL-1, may explain phenomena such as graft nonfunction, rapid rejection, and lack of response to immunosuppression.

Animals↗
PubMed1997

Perfusion patterns during temporal lobe seizures: relationship to surgical outcome.

We sought to determine whether patterns of ictal hyperfusion demonstrated using [99mTC]HMPAO (hexamethylpropylene amine oxime) single photon emission computed tomography (SPECT) predict outcome of temporal lobectomy; in particular, whether the more extensive patterns of ictal hyperperfusion are associated with poor outcome. We studied 63 patients who had ictal SPECT studies prior to temporal lobectomy. Hyperperfusion on ictal SPECT scans was lateralized, and classified into: (i) 'typical', (ii) 'typical with posterior extension', (iii) 'bilateral' and (iv) 'atypical' patterns. Outcome (minimum of 2 years follow-up) was classified as either seizure free, or not seizure free. Actuarial analysis was used to test the relationship of SPECT patterns with outcome. There were 35 cases with the typical ictal SPECT pattern, 13 posterior, nine bilateral and six atypical cases. The atypical pattern was associated with lack of pathology in the surgical specimen. Outcome was similar for the typical, posterior and bilateral with 60%, 69% and 67% seizure free, respectively. In contrast, the atypical group had a worse outcome with only 33% seizure free. Actuarial analysis showed a significant difference in outcome between patients with the typical pattern, and patients with the atypical pattern (P = 0.04). We conclude that extended patterns of ictal perfusion in temporal lobe epilepsy do not predict poor outcome, indicating that extended hyperperfusion probably represents seizure propagation pathways rather than intrinsically epileptogenic tissue. Atypical patterns of hyperperfusion are associated with poor outcome and may indicate diffuse or extra-temporal epileptogenicity.

Actuarial Analysis↗
PubMed1997

Hippocampal atrophy is not a major determinant of regional hypometabolism in temporal lobe epilepsy.

PURPOSE: The pathophysiologic basis for the [18F]fluorodeoxyglucose positron-emission tomography (FDG-PET) temporal lobe hypometabolism in patients with hippocampal sclerosis (HS) is uncertain. We tested the hypothesis that hippocampal atrophy, which is strongly correlated with hippocampal cell loss, is largely responsible for the regional hypometabolism in HS. METHODS: Regions of interest (ROIs) on FDG-PET scanning were determined in the medial, lateral, and posterior temporal lobe, thalamus, and basal ganglia. A right/left asymmetry index for each ROI was calculated. These results were correlated with hippocampal magnetic resonance imaging (MRI) volume ratios. RESULTS: There was no correlation between the magnitudes of the FDG-PET asymmetry index and the MRI volume ratio for the mesial or lateral temporal regions (r = -0.09, r = -0.04). When the right/left asymmetry index was compared with the right/left hippocampal volume ratio, correlations for the mesial temporal ROI (r = 0.79, p < 0.0001) and lateral temporal ROI (r = 0.57, p < 0.0005) were found. These, however, simply indicated that both tests accurately reflect the side of the epileptogenic region. The concordance of the side of relative hypometabolism of the FDG-PET with the side of the hippocampal atrophy was higher for the mesial temporal region (100%) than for the lateral (77.5%). CONCLUSIONS: The lack of correlation between the magnitudes of the ratios argues against hippocampal atrophy and cell loss having a central role in the FDG-PET temporal hypometabolism.

Adult↗
PubMed1996

Plasmapheresis in Rasmussen's encephalitis.

Rasmussen's encephalitis (RE) is a progressive childhood disorder characterized by intractable focal seizures, hemiplegia, dementia, and inflammatory histopathology. The process is typically limited to one cerebral hemisphere. We report four patients with pathologically confirmed RE who were treated with repeated plasmapheresis. Three patients exhibited repeated, dramatic, transient responses to plasmapheresis, manifested by reduced seizure frequency and improved neurologic function. One patient exhibited marginal improvement after treatment with plasmapheresis. These observations indicate that circulating factors, likely autoantibodies, are pathogenic in at least some patients with RE and suggest that RE is an autoimmune disease. Plasmapheresis may be a useful adjunctive therapy in status epilepticus, and can also aid in assessment of residual function in the diseased hemisphere before surgical resection.

Adolescent↗
PubMed1995

Comparative localisation of CRYP alpha, a CAM-like tyrosine phosphatase, and NgCAM in the developing chick visual system.

The avian CRYP alpha gene is expressed in the embryonic nervous system and encodes a receptor-like protein tyrosine phosphatase with structural similarity to neural cell adhesion molecules. To gain further insight into the role of the CRYP alpha phosphatase in neural development, this study addresses the protein's cellular distribution in the well characterised embryonic visual system. High levels of CRYP alpha protein localise in retinal axons extending from the eye to the tectum throughout the major growth periods of these nerve processes. In addition, primitive inner plexiform layer processes in the retina, tectobulbar axons, and non-retinal fibres of the tectal stratum opticum, contain large amounts of CRYP alpha. Its presence in non-fasciculated processes suggests that CRYP alpha has a role other than in fasciculation in short range fibres. In contrast to CRYP alpha, NgCAM is confined largely to axon fascicles in the retina and tectum, consistent with its demonstrated role in fasciculation of cultured neurites. In cultured retinal neurons CRYP alpha proteins reside both in neurite processes and in growth cone membranes, implicating both of these as potential functional locations for the protein. Although CRYP alpha continues to be expressed in the later embryo, the strong, early expression suggests a significant developmental role in the initial growth or guidance of nerve processes. This applies both over the longer range in the retinotectal and tectobulbar projections and over the shorter range within plexiform layers.

Animals↗
PubMed1995

Comparison of ictal SPECT and interictal PET in the presurgical evaluation of temporal lobe epilepsy.

We retrospectively compared ictal technetium 99m hexamethylpropyleneamineoxime single-photon emission computed tomography (SPECT) and interictal 18F-fluorodeoxyglucose positron emission tomography (PET) in 35 patients with well-lateralized temporal lobe epilepsy (TLE). Based on SPECT scans the two observers correctly lateralized seizure foci with certainty in 89% of patients; interobserver agreement was excellent. Both observers incorrectly lateralized the seizure focus on two SPECT scans; one error was explained by rapid electroencephalographic spread to the contralateral side and for the other patient, isotope was injected during a brief aura. Based on PET scans, observers correctly lateralized the foci with certainty in 63% and with lesser confidence in 83%; four incorrect lateralizations were made by one observer and none by the other. PET interobserver disagreement was explained by differences between observers in weighting the relative hypometabolism in medial and lateral temporal regions. The detection rate for PET was lower in the absence of structural imaging abnormalities (60 vs 87%). PET yielded correct lateralizations in the 2 patients for whom SPECT interpretation was difficult. We conclude that both ictal SPECT and interictal PET are sensitive methods for the lateralization of TLE, but SPECT can be interpreted with greater certainty and is more sensitive when magnetic resonance imaging findings are negative. False lateralization is rare with ictal SPECT and can be explained when interpreted in conjunction with electroclinical data. Both investigations have complementary roles when localization is difficult.

Adolescent↗
PubMed1995

SPECT in the localisation of extratemporal and temporal seizure foci.

The yield of ictal, postictal, and interictal SPECT was compared in the localisation of seizure foci in 177 patients with partial epilepsy. In 119 patients with known unilateral temporal lobe epilepsy ictal SPECT (97% correct localisation) was superior to postictal SPECT (71% correct), which was better than interictal studies (48% correct). Similarly, in cases of known or suspected extratemporal epilepsy the yield of ictal SPECT studies was high (92%). By contrast, the yield of postictal studies was much lower (46%) and usually only very early postictal studies were diagnostic. Interictal SPECT was of little value. The accuracy of ictal SPECT in localising temporal lobe seizures is now well established. Extratemporal seizures are often brief and difficult to localise. This report shows that ictal SPECT also has a high diagnostic yield in a wide range of extratemporal epilepsies. The brevity of many extratemporal seizures means that true ictal SPECT examinations can be difficult to achieve, but the high diagnostic yield justifies the special organisational effort needed to obtain such studies.

Epilepsies, Partial↗
PubMed1994

Ictal postictal and interictal single-photon emission tomography in the lateralization of temporal lobe epilepsy.

Single-photon emission tomography (SPET) using radioligands that are fixed on first pass through the cerebral circulation shows distinctive and rapidly changing blood flow patterns accompanying temporal lobe seizures. We sought to determine the optimal time to perform SPET studies for clinical seizure lateralization in temporal lobe epilepsy. Interictal, ictal and postictal SPET scans of 73 consecutively studied patients with unilateral temporal lobe epilepsy were read by three blinded observers to assess the accuracy of lateralization in each condition. The blinded observers correctly identified the side of focus in 97% of ictal studies, 72% of postictal studies and 50% of interictal studies. No incorrect scores were made in the ictal studies, whilst 5% of postictal and 12% of interictal studies were lateralized to the wrong side. Inter-observer agreement was best with the ictal studies. The dramatic perfusion changes of ictal SPET provide consistent, reliable and easily interpretable information that is superior to that provided by interictal and postictal studies. Injection of ligand during seizures is therefore the method of choice for SPET to aid the non-invasive lateralization of temporal seizure foci.

Adult↗
PubMed1994

Parietal lobe epilepsy: clinical features and seizure localization by ictal SPECT.

We studied clinical and ictal single-photon emission computed tomography (SPECT) features in 14 patients with parietal lobe epilepsy, nine of whom had structural parietal lobe lesions. Thirteen patients had simple partial seizures of somatosensory (eight), psychic (four), and motor (nine) types. Complex partial seizures (CPS) occurred in seven patients; six were psychoparetic (prominent staring, relative immobility) and one had hyperkinetic activity. Seizures lasted 7 to 110 seconds; 99mTc-HMPAO (hexamethylpropylene amine oxime) was injected ictally, 7 to 89 seconds from seizure onset and 0 to 74 seconds (mean, 21.0 +/- 24.4 seconds) before seizure termination. Ictal SPECT demonstrated focal areas of parietal hyperperfusion in all 14 cases and corresponded with sites of the structural lesions. Parietal hyperperfusion was anterior in eight, posterior in four, and diffuse in two. Quantitative analysis revealed increases in parietal side-to-side perfusion ratios on ictal compared with interictal scans of 11 to 51% (mean, 25.5 +/- 14.4%). Ictal SPECT localization correlated with two main clinical seizure patterns: an anterior syndrome characterized by sensorimotor manifestations and a posterior syndrome characterized by CPS of the psychoparetic type. Ictal SPECT is helpful for localization of parietal seizures. Parietal hyperperfusion is discrete and short-lived, demanding true ictal injections for diagnostic studies.

Adolescent↗