Biomedical subjects

D R Fish

Publications and source records attributed to D R Fish.

At least 37 records · Page 2Linked to original sources

PubMed1994

Autosomal dominant frontal epilepsy misdiagnosed as sleep disorder.

We describe a distinctive epilepsy syndrome in six families, which is the first partial epilepsy syndrome to follow single gene inheritance. The predominant seizure pattern had frontal lobe seizure semiology with clusters of brief motor attacks occurring in sleep. Onset was usually in childhood, often persisting through adult life. Misdiagnosis as night terrors, nightmares, hysteria, or paroxysmal nocturnal dystonia was common, and the inheritance pattern was often not appreciated. This autosomal dominant epilepsy syndrome is ideal for identification of partial epilepsy genes.

Adolescent↗

PubMed1994

Opiate receptors in idiopathic generalised epilepsy measured with [11C]diprenorphine and positron emission tomography.

The neurochemical basis of absence seizures is uncertain. A previous PET study has provided evidence for release of endogenous opioids from cerebral cortex at the time of absence seizures, but it is has not yet been established whether there is an abnormality of opiate receptor numbers interictally. In the present study, the non-specific opiate receptor ligand, [11C]diprenorphine, was used to measure cerebral opiate receptors interictally in patients with childhood and juvenile absence epilepsy. Eight patients and eight normal controls had a single scan after a high specific activity injection of [11C]diprenorphine. The cerebral volume of distribution (Vd) of [11C]diprenorphine relative to plasma was calculated on a pixel-by-pixel basis. There were no significant differences in [11C]diprenorphine Vd between patients and control subjects in either cortex or thalamus, structures thought to be involved in the pathogenesis of absence seizures. The results suggest that there is no overall abnormality of opioid receptors in patients with childhood and juvenile absence epilepsy. Studies with specific ligands may provide information about the different receptor subtypes.

Adult↗

PubMed1994

A patient-to-computed-tomography image registration method based on digitally reconstructed radiographs.

An automatic method for the accurate registration of computed tomography (CT) data with two camera-calibrated radiographs is presented. The registration is based on the skull as visualized both in the plain radiographs and in radiographs digitally reconstructed from CT. A reference coordinate system is established based on the radiographic projection parameters obtained using an angiographic stereotactic localizer. The CT-derived reconstructed radiographs are aligned iteratively at multiple resolutions until a best match is found by adjusting the position and orientation of the CT data set relative to the reference coordinate system. The results of experiments with a skull phantom performed under stereotactic control which show that reliable registration is possible with an accuracy better than 1 mm are presented. Possible applications include intraoperative patient-to-CT frameless registration and registration of radiographic data with frameless CT for depth electroencephalogram electrode position confirmation.

Algorithms↗

PubMed1994

Subependymal heterotopia: a distinct neuronal migration disorder associated with epilepsy.

Subependymal heterotopia has recently been recognised as a cause of epilepsy, but the clinical and investigational features have not been fully described. The clinical, psychometric, imaging, and electroencephalographic features of 13 adult patients with subependymal heterotopia and epilepsy have been reviewed. Age at seizure onset ranged from 18 months to 20 years (median 13 years). There were significantly more female (12) than male (1) patients (p < 0.01). Diagnosis of subependymal heterotopia was made by MRI in 11 patients and CT in two. The heterotopic grey matter was nodular in 11 patients and diffuse in two; bilateral in eight and unilateral in five. There were significantly more patients with predominant right than left cerebral hemisphere involvement (p < 0.01). The most commonly involved site was the occipital horn of the lateral ventricles (10 of 13 patients). Eleven patients presented with partial epilepsy, 10 of whom also had secondarily generalised seizures. The clinical description of the seizures often suggested either an occipital (four patients) or temporal (five patients) onset. Two patients presented with absence attacks without clear focal features. Patients demonstrated normal early milestones (12 of 13 patients), including normal motor development (all patients) and average or above average intelligence (10 of 13 patients). An EEG examination showed normal background activity in all but two patients, one of whom had large intracranial haematomas. Epileptiform activity was usually widespread (10 of 13 patients) and in three patients, there was generalised 3-Hz spike and wave activity that had previously led to an erroneous diagnosis of concomitant primary generalised epilepsy. Onset of epilepsy in the second decade of life, normal developmental milestones and intelligence, and the finding of an overwhelming female preponderance differentiates subependymal heterotopia from other cortical dysgeneses. The female preponderance supports the importance of the X chromosome and sex steroids in the maturation and development of the cerebral cortex.

Adult↗

PubMed1994

Image guided audit of surgery for temporal lobe epilepsy.

Studies on surgery for temporal lobe epilepsy are hampered by lack of information about the actual surgery that has taken place. A method is described for accurately measuring the volumes of resection by MRI after surgery. Ten cases of surgically treated temporal lobe epilepsy (nine non-tailored resections, one selective amygdalohippocampectomy) are presented to show the technique. Indices of extent of resection in both the mesiobasal and lateral temporal lobe compartments have been measured, compared, and evaluated. By comparison with identical preoperative volumetric MRI the hippocampal resections have been correlated with the demonstrated hippocampal volume loss, thought to be of relevance in the aetiology of temporal lobe epilepsy. Detailed postoperative audit in this manner is vital in providing a rational basis for follow up studies of outcome.

Adolescent↗

PubMed1994

Association of hippocampal sclerosis with cortical dysgenesis in patients with epilepsy.

The possible dual occurrence of hippocampal sclerosis (HS) and other structural lesions (especially cortical dysgenesis [CD]) is well established in patients with chronic partial epilepsy. We describe the frequency of additional CD in a series of 100 patients with evidence of HS, using volumetric MRI. Additional, often subtle, CD was present in 15 patients: subependymal heterotopia (six), forme fruste of tuberous sclerosis (two), focal macrogyria (two), focal cortical dysplasia (one), laminar heterotopia (one), bilateral schizencephaly (one), and simplified gyral patterns (two). In contrast, in 46 healthy volunteers, only one had possible CD (p < 0.05). Only 2 of 15 patients had a history of childhood febrile convulsions. HS is a heterogeneous condition; patients being evaluated for temporal lobe surgery should be carefully screened for additional CD using appropriate MR techniques.

Adolescent↗

PubMed1993

Hippocampal sclerosis in epilepsy and childhood febrile seizures.

The connection between hippocampal sclerosis and childhood febrile seizures (CFS) is a contentious issue in the study of epilepsy. We investigated 107 patients with drug-resistant epilepsy by high-resolution volumetric magnetic resonance imaging (MRI). 20 had a history of CFS, 45 had focal (26) or diffuse (19) hippocampal volume loss (HVL). The frequency of CFS was significantly (p < 0.001) higher in the patients with HVL, especially of the diffuse pattern, compared to other epileptic patients without HVL and to the general population. Furthermore, the severity of HVL was greatest in those with a history of CFS. No other clinical or demographic features were associated with either a history of CFS or HVL. The frequency of CFS in patients with other structural congenital causes of epilepsy did not differ from that in a general population. Although these findings show that hippocampal sclerosis is strongly associated with a history of CFS, they do not indicate whether this is a causal relationship. If CFS do cause some cases of hippocampal sclerosis, this can not be the only mechanism, as 64% of those with HVL gave no history of CFS. As diffuse HVL is more strongly associated with a history of CFS than focal HVL, it is also possible that CFS convert pre-existing congenital focal abnormalities into diffuse hippocampal sclerosis. Given the possibility that CFS may cause hippocampal damage and epilepsy, they require urgent medical intervention.

Adolescent↗

PubMed1993

A specialised computer-based monitoring system for intraoperative electrocorticography.

We have developed a computer-based intraoperative ECoG monitoring system which offers the flexibility of digital recording and allows detailed review of recorded events without interrupting monitoring. In addition, a diagram showing the electrode positions on the brain can be generated on computer screen and subsequently displayed during monitoring--this allows automatic indication of the electrode positions corresponding to specific ECoG channels and can provide the surgeon with a clear visual impression of the area of spiking.

Cerebral Cortex↗

PubMed1992

Is nocturnal paroxysmal dystonia a form of frontal lobe epilepsy?

The sex ratio, age at onset, and ictal features of nine patients with nocturnal paroxysmal dystonia were compared with those of eight patients with daytime frontal lobe seizures and eight patients with nocturnal motor attacks of known epileptic origin. All patients underwent video electroencephalography telemetry. There were no clinical features that would allow distinction between the groups and no single phenomenon was uniquely seen in nocturnal paroxysmal dystonia. This study provides no evidence that nocturnal paroxysmal dystonia is a separate diagnostic entity.

Adolescent↗

PubMed1992

Open stereotactic selective amygdalo-hippocampectomy for drug resistant epilepsy.

Selective removal of the medio-basal temporal structures has been introduced as an alternative to standard temporal lobectomy in the treatment of intractable temporal lobe epilepsy not related to gross structural lesions. Various approaches have been described for the surgical excision of the amygdalo-hippocampal complex, each of them presenting advantages and limitations. The recently introduced computer-assisted technique of volumetric stereotactic excision of deep-seated intracerebral lesions combines precision of targeting with elimination of unnecessary cortical trauma and may potentially provide an alternative method in the treatment of temporal lobe epilepsy. We present our experience of stereotactic volumetric selective amygdalo-hippocampectomy in six patients with medically intractable temporal lobe epilepsy. The criteria for selection, the pre-operative evaluation and the operative technique are discussed. All patients had a cessation or considerable reduction in seizure frequency while the morbidity was minimal.

Adolescent↗

PubMed1992

Very high-frequency rhythmic activity during SEEG suppression in frontal lobe epilepsy.

Intracerebral EEG (SEEG) recordings showing the development of fast rhythmic activity at seizure onset provide important evidence for the localisation of an epileptic focus. However, very high-frequency activity (greater than 50 Hz) of low amplitude relative to the background may not be apparent on the paper record due to the limited bandwidth and dynamic range of conventional SEEG recording and display methods. The use of a digital telemetry system with a fast sampling rate (400 Hz) and a wide dynamic range (1 microV resolution, 4 mV range) has allowed us to utilize expanded time scale SEEG plots and autoregressive spectral estimation to identify this activity in chronic SEEG studies. This may be particularly useful in frontal lobe epilepsy, where rapid propagation often prevents adequate localization using conventional methods of analysis.

Adult↗

PubMed1992

Hippocampal volumetric and morphometric studies in frontal and temporal lobe epilepsy.

The most common temporal lobe pathology is Ammons Horn sclerosis (AHS), and several different imaging techniques have been utilized to detect this with varying success. We describe the clinical application of magnetic resonance imaging (MRI) using a three-dimensional volume technique which allows total hippocampal volume to be measured and symmetry evaluated. Hippocampal surface area was calculated in sequential 1.5 mm thick contiguous images, using a GE IC workstation. Total volumes and surface areas were calculated. The cross-sectional surface area at 1.5 mm intervals was displayed graphically, permitting morphometric analysis of the hippocampus throughout its length. Focal atrophy within any part of the hippocampal formation (HF) and its extent could thus be assessed. Patients with well-lateralized temporal lobe epilepsy (TLE) (n = 20) and well-defined frontal lobe epilepsy (FLE) (n = 20) were studied, and volumes compared with normal values derived from 10 neurologically normal controls. Asymmetric hippocampal volume loss was demonstrated in all 20 patients with clinically typed TLE, but not in normal controls or patients with FLE. Volume loss distribution was anterior in 12 patients, posterior in one patient and widespread in seven patients. Secondarily generalized seizures were strongly associated with widespread loss. This method of surface area and volumetric analysis of the hippocampus in TLE can demonstrate asymmetry and focal involvement, and help distinguish between hippocampal and frontal pathologies.

Adult↗

PubMed1992

Effect of a single 30-minute treatment of high voltage pulsed current on edema formation in frog hind limbs.

The purpose of this study was to investigate the effect of a single treatment of high voltage pulsed current (HVPC) on edema formation. Twenty-four frogs were anesthetized, and both hind limbs of each frog were traumatized by impact. Limb volumes were measured by water displacement immediately before and after trauma and at predetermined intervals for 24.0 hours posttrauma. One limb of each frog was randomly selected to receive 30 minutes of continuous, 120-pulse per second, cathodal HVPC at voltages 10% less than motor threshold levels. Data were analyzed by an analysis of variance for repeated measures. Sources of significant differences were determined by paired t tests (probability values determined by Bonferroni adjustment). A single 30-minute application of HVPC significantly curbed edema formation for between 4.0 and 7.5 hours following treatment (ie, volumes of treated limbs were significantly less than those of untreated limbs). These results suggest that regimens currently applied to humans (ie, one treatment per day or three times per week) may be insufficiently aggressive to provide sustained treatment effects.

Animals↗

PubMed1992

Effect of electrically induced muscle contractions on posttraumatic edema formation in frog hind limbs.

We tested the hypothesis that repeated muscle contractions induced by high voltage pulsed current (HVPC) would limit volume increases in traumatized frog hind limbs. Twelve frogs were anesthetized, and both hind limbs of each frog were traumatized by impact. Limb volumes were measured via water displacement over a 24-hour period. Four 30-minute treatments of continuous 1-pulse per second HVPC were applied to one limb selected randomly. Stimulation produced muscle contractions that resulted in minimal joint movements. Volume changes from pretrauma limb volumes (in milliliters per kilogram) were analyzed by an analysis of variance for repeated measures. Our hypothesis was rejected (ie, repeated muscle contractions, as induced in this study, did not limit posttraumatic edema formation in frogs). Further investigation of the relative influences of limb position and varying pulse rates, pulse durations, and intensities of HVPC on edema formation may provide valuable insights on effective treatment of edema in humans.

Animals↗

PubMed1992

Effects of low voltage pulsed current on edema formation in frog hind limbs following impact injury.

The purpose of this study was to test the effect of low voltage pulsed current (LVPC) on posttraumatic edema formation in frog hind limbs. Feet of 26 anesthetized bullfrogs were systematically injured by weight drop. One hind limb of each animal was randomly selected to receive continuous 100-pps LVPC at 90% of motor threshold; the opposite hind limb served as a control. A series of four 30-minute treatments (interrupted by 30-minute rests) was begun minutes after injury. Changes from pretrauma limb volumes were determined before and after each treatment and at 8, 17, 20, and 24 hours posttrauma. Analysis of variance revealed no significant treatment effect. Similar studies utilizing high voltage pulsed current (HVPC) at 90% of motor threshold revealed significant curbing of edema formation in frogs. Waveform (LVPC versus HVPC) seems to influence the efficacy of electrotherapy for edema control.

Analysis of Variance↗

PubMed1992

Influence of high voltage pulsed current on edema formation following impact injury in rats.

High voltage pulsed current (HVPC) has been shown to be effective in curbing posttraumatic edema formation in frogs. The purpose of this study was to establish the utility of HVPC in controlling edema formation in a mammalian model. Both feet of 20 anesthetized rats were traumatized following initial determination of hind-limb volumes. Four 30-minute cathodal HVPC treatments at 120 pulses per second and 90% of visible motor threshold interspersed with 30-minute rest periods were applied to one randomly selected hind limb of each rat via the immersion technique. The other hind limb served as a control. Limb volumes were measured after each treatment and rest period. All data were expressed as changes from pretrauma limb volumes in milliliters per kilogram of body weight; these data were analyzed by repeated-measures analyses of variance and post hoc paired t tests. Volumes of untreated limbs were significantly greater than volumes of treated limbs after the second treatment. Evidence of significant treatment effects in frogs, and now rats, provides a compelling rationale for initiating trials of efficacy of cathodal HVPC in inhibiting acute edema formation in humans.

Animals↗

PubMed1991

The effect of sleep on the dyskinetic movements of Parkinson's disease, Gilles de la Tourette syndrome, Huntington's disease, and torsion dystonia.

The effect of sleep on the involuntary movements or dyskinesias in Parkinson's disease, Huntington's disease, primary and secondary torsion dystonia, and Gilles de la Tourette syndrome was studied in a total of 52 patients and 10 normal subjects using video electroencephalographic telemetry. Movements typical of the wake pattern were seen occasionally during unequivocal sleep in all but two completed studies, and in each condition reappeared under similar circumstances. The movements were most likely to occur after awakenings or lightenings of sleep, or in stage one sleep. The movements were very rare during the deeper phases of sleep. Those movements that occurred during sleep without awakenings were usually preceded by arousal phenomena and, rarely, by sleep spindles or slow waves. The control group showed normal "semipurposeful" movements under the same conditions during sleep. The rare appearance of the different dyskinesias and normal movements under similar circumstances during sleep could be a result of common effects on the generator systems or changes in the excitability of the final common motor pathway.

Brain↗

PubMed1991

Effect of anodal high voltage pulsed current on edema formation in frog hind limbs.

We have recently demonstrated that some forms of cathodal high voltage pulsed current (HVPC) curb posttraumatic edema formation in frog hind limbs. The purpose of this study was to determine, by assessing the capacity of anodal HVPC to curb posttraumatic edema formation, whether polarity is an important variable. Fourteen anesthetized bullfrogs were placed on large dispersive electrodes lining body slings that maintained the frogs' limbs in a dependent position throughout data collection. The frogs' feet were traumatized by impact following initial measurement of limb volumes. At the commencement of each of four 30-minute treatments, hind limbs were immersed in separate beakers and briefly stimulated until motor threshold was determined. One limb, randomly selected, received anodal HVPC at 90% of motor threshold and 120 pulses per second; the other limb served as a control. Treatments were followed by 30-minute rests. Limb volumes were measured by water displacement immediately after trauma and following each treatment and rest period. Data were expressed as changes from pretrauma volumes in milliliters per kilogram of body weight. A repeated-measures analysis of variance was used to test for treatment effect. Despite an aggressive series of treatments, virtually symmetrical bilateral edema occurred; therefore, no treatment effect was evident. This result contrasts with treatment effects previously reported for cathodal HVPC.

Analysis of Variance↗