Deep brain stimulation in tourette syndrome: a description of 3 patients with excellent outcome

Tourette syndrome (TS) is a complex neuropsychiatric disorder often starting in childhood and characterized by the presence of multiple motor and vocal tics and psychiatric comorbidities. Patients with TS usually respond to medical treatment, and the condition often improves during adolescence; however, surgery has been considered a possible approach for the subset of patients with ongoing medically refractory disease. Ablative procedures have been associated with unsatisfactory results and major adverse effects, prompting trials of deep brain stimulation (DBS) as an alternative therapy. It remains unclear which of the various nuclear targets is most effective in TS. We describe 3 patients with TS who underwent DBS targeting the bilateral thalamic centromedian/parafascicular complex (CM/Pf) with an excellent clinical outcome. At 1-year follow-up, the mean reduction in the total Yale Global Tic Severity Scale score in the 3 patients was 70% (range, 60%-80%).Our study further supports the role of the CM/Pf DBS target in medically intractable TS.

Underlying neurobiology and clinical correlates of mania status after subthalamic nucleus deep brain stimulation in Parkinson's disease: a review of the literature

Deep brain stimulation (DBS) is a novel and effective surgical intervention for refractory Parkinson's disease (PD). The authors review the current literature to identify the clinical correlates associated with subthalamic nucleus (STN) DBS-induced hypomania/mania in PD patients. Ventromedial electrode placement has been most consistently implicated in the induction of STN DBS-induced mania. There is some evidence of symptom amelioration when electrode placement is switched to a more dorsolateral contact. Additional clinical correlates may include unipolar stimulation, higher voltage (>3 V), male sex, and/or early-onset PD. STN DBS-induced psychiatric adverse events emphasize the need for comprehensive psychiatric presurgical evaluation and follow-up in PD patients. Animal studies and prospective clinical research, combined with advanced neuroimaging techniques, are needed to identify clinical correlates and underlying neurobiological mechanisms of STN DBS-induced mania. Such working models would serve to further our understanding of the neurobiological underpinnings of mania and contribute valuable new insight toward development of future DBS mood-stabilization therapies.

Statistical parametric mapping demonstrates asymmetric uptake with Tc-99m ECD and Tc-99m HMPAO SPECT in normal brain

Tc-99m ethyl cysteinate diethylester (ECD) and Tc-99m hexamethyl propylene amine oxime (HMPAO) are commonly used for single-photon emission computed tomography (SPECT) studies of a variety of neurologic disorders. Although these tracers have been very helpful in diagnosing and guiding treatment of neurologic disease, data describing the distribution and laterality of these tracers in normal resting brain are limited. Advances in quantitative functional imaging have demonstrated the value of using resting studies from control populations as a baseline to account for physiologic fluctuations in cerebral perfusion. Here, we report results from 30 resting Tc-99m ECD SPECT scans and 14 resting Tc-99m HMPAO scans of normal volunteers with no history of neurologic disease. Scans were analyzed with regions of interest and with statistical parametric mapping, with comparisons performed laterally (left vs. right), as well as for age, gender, and handedness. The results show regions of significant asymmetry in the normal controls affecting widespread areas in the cerebral hemispheres, but most marked in superior parietotemporal region and frontal lobes. The results have important implications for the use of normal control SPECT images in the evaluation of patients with neurologic disease.

Surgery for movement disorders

Over past three decades, there has been a resurgence of interest in functional neurosurgery for movement disorders. Recently, thanks to the increased understanding of cellular pathophysiology and advances in technology and surgical techniques, deep brain stimulation (DBS) has essentially replaced ablative procedures for most of these conditions. Success of DBS treatment in the movement disorders depends on the recognized limitations in the medical treatment, our understanding of the anatomy and physiology of these disorders and, particularly, involvement of neurologists, neurosurgeons, clinical neurophysiologists and neuropsychiatrists in outcome studies of DBS surgery. Up to now, the exact mechanism of DBS is not fully understood. This review provides an overview of use of stereotactic neurosurgery, particularly DBS, for movement disorders, focusing mainly on the patient selection, target options, clinical outcome, adverse effects and possible mechanisms of DBS for advanced Parkinson's disease, dystonia, and essential tremor.

Data mining neocortical high-frequency oscillations in epilepsy and controls

Transient high-frequency (100-500 Hz) oscillations of the local field potential have been studied extensively in human mesial temporal lobe. Previous studies report that both ripple (100-250 Hz) and fast ripple (250-500 Hz) oscillations are increased in the seizure-onset zone of patients with mesial temporal lobe epilepsy. Comparatively little is known, however, about their spatial distribution with respect to seizure-onset zone in neocortical epilepsy, or their prevalence in normal brain. We present a quantitative analysis of high-frequency oscillations and their rates of occurrence in a group of nine patients with neocortical epilepsy and two control patients with no history of seizures. Oscillations were automatically detected and classified using an unsupervised approach in a data set of unprecedented volume in epilepsy research, over 12 terabytes of continuous long-term micro- and macro-electrode intracranial recordings, without human preprocessing, enabling selection-bias-free estimates of oscillation rates. There are three main results: (i) a cluster of ripple frequency oscillations with median spectral centroid = 137 Hz is increased in the seizure-onset zone more frequently than a cluster of fast ripple frequency oscillations (median spectral centroid = 305 Hz); (ii) we found no difference in the rates of high frequency oscillations in control neocortex and the non-seizure-onset zone neocortex of patients with epilepsy, despite the possibility of different underlying mechanisms of generation; and (iii) while previous studies have demonstrated that oscillations recorded by parenchyma-penetrating micro-electrodes have higher peak 100-500 Hz frequencies than penetrating macro-electrodes, this was not found for the epipial electrodes used here to record from the neocortical surface. We conclude that the relative rate of ripple frequency oscillations is a potential biomarker for epileptic neocortex, but that larger prospective studies correlating high-frequency oscillations rates with seizure-onset zone, resected tissue and surgical outcome are required to determine the true predictive value.

Swine model for translational research of invasive intracranial monitoring

Focal cortical epilepsy is currently studied most effectively in humans. However, improvement in cortical monitoring and investigational device development is limited by lack of an animal model that mimics human acute focal cortical epileptiform activity under epilepsy surgery conditions. Therefore, we assessed the swine model for translational epilepsy research. Swine were used due to their cost-effectiveness, convoluted cortex, and comparative anatomy. The anatomy has all the same brain structures as the human, and in similar locations. Focal subcortical injection of benzyl-penicillin produced clinical seizures correlating with epileptiform activity demonstrating temporal and spatial progression. Swine were evaluated under five different anesthesia regimens. Of the five regimens, conditions similar to human intraoperative anesthesia, including continuous fentanyl with low dose isoflorane, was the most effective for eliciting complex, epileptiform activity after benzyl-penicillin injection. The most complex epileptiform activity (spikes, and high frequency activity) was then repeated reliably in nine animals, utilizing 14 swine total. There were 20.1 ± 10.8 [95% confidence interval (CI) 11.8-28.4] epileptiform events with > 3.5 Hz activity occurring per animal. Average duration of each event was 46.3 ± 15.6 (95% CI 44.0-48.6) s, ranging from 20-100 s. In conclusion, the acute swine model of focal cortical epilepsy surgery provides an animal model that mimics human surgical conditions with a large brain and gyrated cortex, and is relatively inexpensive among animal models. Therefore, we feel this model provides a valuable, reliable, and novel platform for translational studies of implantable hardware for intracranial monitoring.

Strengthening clinical cancer research in the United Kingdom

BACKGROUND

In 1999, 270,000 cases of cancer were registered in the United Kingdom, placing a large burden on the NHS. Cancer outcome data in 1999 suggested that UK survival rates were poorer than most other European countries. In the same year, a Department of Health review noted that clinical trials accrual was poor (<3.5% of incident cases) and hypothesised that increasing research activity might improve outcomes and reduce the variability of outcomes across England. Thus, the National Cancer Research Network (NCRN) was established to increase participation in cancer clinical research.

METHODS

The NCRN was established in 2001 to provide a robust infrastructure for cancer clinical research and improvements in patient care. Remit of NCRN is to coordinate, support and deliver cancer clinical research through the provision of research support staff across England. The NCRN works closely with similar networks in Scotland, Wales and the Northern Ireland. A key aim of NCRN is to improve the speed of research and this was also assessed by comparing the speed of study delivery of a subset of cancer studies opening before and after NCRN was established.

RESULTS

Patient recruitment increased through NCRN, with almost 32,000 (12% of annual incident cases) cancer patients being recruited each year. Study delivery has improved, with more studies meeting the recruitment target - 74% compared with 39% before NCRN was established.

CONCLUSION

The coordinated approach to cancer clinical research has demonstrated increased accrual, wide participation and successful trial delivery, which should lead to improved outcomes and care.

Utility of independent component analysis for interpretation of intracranial EEG

Electrode arrays are sometimes implanted in the brains of patients with intractable epilepsy to better localize seizure foci before epilepsy surgery. Analysis of intracranial EEG (iEEG) recordings is typically performed in the electrode channel domain without explicit separation of the sources that generate the signals. However, intracranial EEG signals, like scalp EEG signals, could be linear mixtures of local activity and volume-conducted activity arising in multiple source areas. Independent component analysis (ICA) has recently been applied to scalp EEG data, and shown to separate the signal mixtures into independently generated brain and non-brain source signals. Here, we applied ICA to unmix source signals from intracranial EEG recordings from four epilepsy patients during a visually cued finger movement task in the presence of background pathological brain activity. This ICA decomposition demonstrated that the iEEG recordings were not maximally independent, but rather are linear mixtures of activity from multiple sources. Many of the independent component (IC) projections to the iEEG recording grid were consistent with sources from single brain regions, including components exhibiting classic movement-related dynamics. Notably, the largest IC projection to each channel accounted for no more than 20–80% of the channel signal variance, implying that in general intracranial recordings cannot be accurately interpreted as recordings of independent brain sources. These results suggest that ICA can be used to identify and monitor major field sources of local and distributed functional networks generating iEEG data. ICA decomposition methods are useful for improving the fidelity of source signals of interest, likely including distinguishing the sources of pathological brain activity.

Synchrony in normal and focal epileptic brain: the seizure onset zone is functionally disconnected

Synchronization of local and distributed neuronal assemblies is thought to underlie fundamental brain processes such as perception, learning, and cognition. In neurological disease, neuronal synchrony can be altered and in epilepsy may play an important role in the generation of seizures. Linear cross-correlation and mean phase coherence of local field potentials (LFPs) are commonly used measures of neuronal synchrony and have been studied extensively in epileptic brain. Multiple studies have reported that epileptic brain is characterized by increased neuronal synchrony except possibly prior to seizure onset when synchrony may decrease. Previous studies using intracranial electroencephalography (EEG), however, have been limited to patients with epilepsy. Here we investigate neuronal synchrony in epileptic and control brain using intracranial EEG recordings from patients with medically resistant partial epilepsy and control subjects with intractable facial pain. For both epilepsy and control patients, average LFP synchrony decreases with increasing interelectrode distance. Results in epilepsy patients show lower LFP synchrony between seizure-generating brain and other brain regions. This relative isolation of seizure-generating brain underlies the paradoxical finding that control patients without epilepsy have greater average LFP synchrony than patients with epilepsy. In conclusion, we show that in patients with focal epilepsy, the region of epileptic brain generating seizures is functionally isolated from surrounding brain regions. We further speculate that this functional isolation may contribute to spontaneous seizure generation and may represent a clinically useful electrophysiological signature for mapping epileptic brain.

Surgically treated movement disorders associated with heterotopia: report of 2 cases

Heterotopic gray matter has been implicated in epilepsy; however, not much is known regarding heterotopia beyond epilepsy. Here, the authors describe 2 pediatric patients with deep heterotopias contiguous with basal ganglia structures. These heterotopias appear to have manifested as movement disorders. One patient presented with a left-sided myoclonus and choreiform movements associated with a right caudate heterotopia; she experienced vast improvement after resection of periventricular heterotopia. The other patient presented with progressive dystonia and a ballistic movement disorder. Initial bilateral globus pallidus internus stimulation resulted in successful treatment of the dystonia; however, her movement disorder worsened. After an extensive workup, including STATISCOM (statistical ictal SPECT coregistered to MR imaging), the patient underwent cortical stimulation with improvement in her movement disorder. To the best of our knowledge, these cases are the first reported instances of heterotopic gray matter associated with movement disorders. Both patients experienced significant improvements following resection of their heterotopias.

Unsupervised classification of high-frequency oscillations in human neocortical epilepsy and control patients

High-frequency oscillations (HFOs) have been observed in animal and human intracranial recordings during both normal and aberrant brain states. It has been proposed that the relationship between subclasses of these oscillations can be used to identify epileptic brain. Studies of HFOs in epilepsy have been hampered by selection bias arising primarily out of the need to reduce the volume of data so that clinicians can manually review it. In this study, we introduce an algorithm for detecting and classifying these signals automatically and demonstrate the tractability of analyzing a data set of unprecedented size, over 31,000 channel-hours of intracranial electroencephalographic (iEEG) recordings from micro- and macroelectrodes in humans. Using an unsupervised approach that does not presuppose a specific number of clusters in the data, we show direct evidence for the existence of distinct classes of transient oscillations within the 100- to 500-Hz frequency range in a population of nine neocortical epilepsy patients and two controls. The number of classes we find, four (three plus one putative artifact class), is consistent with prior studies that identify "ripple" and "fast ripple" oscillations using human-intensive methods and, additionally, identifies a less examined class of mixed-frequency events.

Microseizures and the spatiotemporal scales of human partial epilepsy

Focal seizures appear to start abruptly and unpredictably when recorded from volumes of brain probed by clinical intracranial electroencephalograms. To investigate the spatiotemporal scale of focal epilepsy, wide-bandwidth electrophysiological recordings were obtained using clinical macro- and research microelectrodes in patients with epilepsy and control subjects with intractable facial pain. Seizure-like events not detectable on clinical macroelectrodes were observed on isolated microelectrodes. These 'microseizures' were sparsely distributed, more frequent in brain regions that generated seizures, and sporadically evolved into large-scale clinical seizures. Rare microseizures observed in control patients suggest that this phenomenon is ubiquitous, but their density distinguishes normal from epileptic brain. Epileptogenesis may involve the creation of these topographically fractured microdomains and ictogenesis (seizure generation), the dynamics of their interaction and spread.

Multiscale electrophysiology format: an open-source electrophysiology format using data compression, encryption, and cyclic redundancy check

Continuous, long-term (up to 10 days) electrophysiological monitoring using hybrid intracranial electrodes is an emerging tool for presurgical epilepsy evaluation and fundamental investigations of seizure generation. Detection of high-frequency oscillations and microseizures could provide valuable insights into causes and therapies for the treatment of epilepsy, but requires high spatial and temporal resolution. Our group is currently using hybrid arrays composed of up to 320 micro- and clinical macroelectrode arrays sampled at 32 kHz per channel with 18-bits of A/D resolution. Such recordings produce approximately 3 terabytes of data per day. Existing file formats have limited data compression capabilities, and do not offer mechanisms for protecting patient identifying information or detecting data corruption during transmission or storage. We present a novel file format that employs range encoding to provide a high degree of data compression, a three-tiered 128-bit encryption system for patient information and data security, and a 32-bit cyclic redundancy check to verify the integrity of compressed data blocks. Open-source software to read, write, and process these files are provided.

Metadata and annotations for multi-scale electrophysiological data

The increasing use of high-frequency (kHz), long-duration (days) intracranial monitoring from multiple electrodes during pre-surgical evaluation for epilepsy produces large amounts of data that are challenging to store and maintain. Descriptive metadata and clinical annotations of these large data sets also pose challenges to simple, often manual, methods of data analysis. The problems of reliable communication of metadata and annotations between programs, the maintenance of the meanings within that information over long time periods, and the flexibility to re-sort data for analysis place differing demands on data structures and algorithms. Solutions to these individual problem domains (communication, storage and analysis) can be configured to provide easy translation and clarity across the domains. The Multi-scale Annotation Format (MAF) provides an integrated metadata and annotation environment that maximizes code reuse, minimizes error probability and encourages future changes by reducing the tendency to over-fit information technology solutions to current problems. An example of a graphical utility for generating and evaluating metadata and annotations for "big data" files is presented.

On the recording reference contribution to EEG correlation, phase synchrony, and coherence

The degree of synchronization in electroencephalography (EEG) signals is commonly characterized by the time-series measures, namely, correlation, phase synchrony, and magnitude squared coherence (MSC). However, it is now well established that the interpretation of the results from these measures are confounded by the recording reference signal and that this problem is not mitigated by the use of other EEG montages, such as bipolar and average reference. In this paper, we analyze the impact of reference signal amplitude and power on EEG signal correlation, phase synchrony, and MSC. We show that, first, when two nonreferential signals have negative correlation, the phase synchrony and the absolute value of the correlation of the two referential signals may have two regions of behavior characterized by a monotonic decrease to zero and then a monotonic increase to one as the amplitude of the reference signal varies in [0, +∞). It is notable that even a small change of the amplitude may lead to significant impact on these two measures. Second, when two nonreferential signals have positive correlation, the correlation and phase-synchrony values of the two referential signals can monotonically increase to one (or monotonically decrease to some positive value and then monotonically increase to one) as the amplitude of the reference signal varies in [0, +∞). Third, when two nonreferential signals have negative cross-power, the MSC of the two referential signals can monotonically decrease to zero and then monotonically increase to one as reference signal power varies in [0, +∞). Fourth, when two nonreferential signals have positive cross-power, the MSC of the two referential signals can monotonically increase to one as the reference signal power varies in [0, +∞). In general, the reference signal with small amplitude or power relative to the signals of interest may decrease or increase the values of correlation, phase synchrony, and MSC. However, the reference signal with high relative amplitude or power will always increase each of the three measures. In our previous paper, we developed a method to identify and extract the reference signal contribution to intracranial EEG (iEEG) recordings. In this paper, we apply this approach to referential iEEG recorded from human subjects and directly investigate the contribution of recording reference on correlation, phase synchrony, and MSC. The experimental results demonstrate the significant impact that the recording reference may have on these bivariate measures.

Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data

The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information.

Automatic identification and removal of scalp reference signal for intracranial EEGs based on independent component analysis

The pursuit of an inactive recording reference is one of the oldest technical problems in electroencephalography (EEG). Since commonly used cephalic references contaminate EEG and can lead to misinterpretation, extraction of the reference contribution is of fundamental interest. Here, we apply independent component analysis (ICA) to intracranial recordings and propose two methods to automatically identify and remove the reference based on the assumption that the scalp reference is independent from the local and distributed intracranial sources. This assumption, supported by our results, is generally valid because the reference scalp electrode is relatively electrically isolated from the intracranial electrodes by the skull's high resistivity. We point out that the linear model is underdetermined when the reference is considered as a source, and discuss one special underdetermined case for which a unique class of outputs can be separated. For this case most ICA algorithms can be applied, and we argue that intracranial or scalp EEGs follow this special case. We apply the two proposed methods to intracranial EEGs from three patients undergoing evaluation for epilepsy surgery, and compare the results to bipolar and average reference recordings. The proposed methods should have wide application in quantitative EEG studies.

An international field study of the reliability and validity of a disease-specific questionnaire module (the QLQ-MY20) in assessing the quality of life of patients with multiple myeloma

AIM

To test the reliability, validity and sensitivity of the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-MY24 questionnaire, designed to assess the quality of life of myeloma patients with the QLQ-C30.

METHODS

The study was carried out through the EORTC Quality of Life Group using clinical trials in seven countries. All trials used the QLQ-C30 and QLQ-MY24 at baseline and a follow-up timepoint.

RESULTS

Two hundred and forty patients participated. The questionnaires were acceptable to patients. The hypothesised scale structure (disease symptoms, side-effects, body image and future perspective) was confirmed by multi-trait scaling, internal consistency and correlation analysis. Most scales demonstrated sensitivity to change and discriminated between clinically different patients. The social support scale (4 items) was removed due to observed ceiling effects.

CONCLUSION

The final questionnaire contains 20 items, QLQ-MY20, and is a reliable and valid instrument recommended for use with the QLQ-C30 in myeloma patients.

The impact of a school-based nutrition education intervention on dietary intake and cognitive and attitudinal variables relating to fruits and vegetables

Objective

To assess the impact of a school-based nutrition education intervention aimed at increasing the consumption of fruits and vegetables.

Design

The intervention programme increased the provision of fruits and vegetables in schools and provided a range of point-of-purchase marketing materials, newsletters for children and parents, and teacher information. Curriculum materials at age 6–7 and 10–11 years were also developed and utilised. Evaluation was undertaken with groups of younger (aged 6–7 years) and older (aged 10–11 years) children. Methods included 3-day dietary records with interview and cognitive and attitudinal measures at baseline, with follow-up at 9 months, in intervention and control schools.

Setting

The work was undertaken in primary schools in Dundee, Scotland.

Subjects

Subjects comprised 511 children in two intervention schools with a further 464 children from two schools acting as controls.

Results

Children (n = 64) in the intervention schools had an average increase in fruit intake (133±1.9 to 183±17.0 g day-1) that was significantly (P < 0.05) greater than the increase (100±11.7 to 107±14.2 g day-1) estimated in children (n = 65) in control schools. No other changes in food or nutrient intake were detected. Increases in scores for variables relating to knowledge about fruits and vegetables and subjective norms were also greater in the intervention than in the control group, although taste preferences for fruits and vegetables were unchanged.

Conclusions

It is concluded that a whole school approach to increasing intakes of fruits and vegetables has a modest but significant effect on cognitive and attitudinal variables and on fruit intake.

A randomised study of whole-breast vs tumour-bed irradiation after local excision and axillary dissection for early breast cancer

AIMS

Whole-breast radiotherapy (WBRT) after conservative surgery for early breast cancer is a routine standard of care. Despite this, a number of uncertainties in management still exist. Over recent years, a number of new technologies have allowed the development of partial-breast irradiation, with the intention of improving the risk-benefit relationship of routine breast radiotherapy. We report the results of a trial comparing partial- with WBRT, with prolonged follow-up.

MATERIALS AND METHODS

Between 1986 and 1990, 174 women were randomised to receive conventional whole-breast radiotherapy (WBRT) (40 Gy in 15 fractions), with a tumour-bed boost or partial-breast irradiation by a variety of techniques. Recruitment was problematic, and the trial closed prematurely well before meeting its recruitment target.

RESULTS

A trend was observed towards higher local recurrence and a higher locoregional recurrence rate after irradiation of the tumour bed alone. Distant recurrence and survival were the same.

CONCLUSIONS

Conclusions are limited in view of the failure to complete accrual of the target of 400 participants, and in the context of the techniques of partial-breast radiotherapy used during this study, which would not compare with those in current use. Tumour-bed irradiation alone cannot currently be recommended as routine treatment outside the context of clinical trial.

"Hello, hello--it's English I speak!": a qualitative exploration of patients' understanding of the science of clinical trials

Informed consent may be seriously compromised if patients fail to understand the experimental nature of the trial in which they are participating. Using focus groups, the authors explored how prospective trial participants interpret and understand the science of clinical trials by using patient information sheets relative to their medical condition. An opportunity was provided to hear in the patients' own words how they interpret the information and why there is variable understanding. Respondents struggled to comprehend the meaning and purpose of concepts such as randomisation and double blinding, and found them threatening to their ideas of medical care. Suggestions are made about how to improve the national guidelines on written information for trial participants and pretesting of the information sheets is advocated.

Successful Treatment of Status Migrainosus After Electroconvulsive Therapy With Dihydroergotamine

We describe a case of status migrainosus precipitated by electroconvulsive therapy (ECT) that was refractory to treatment with triptan medications but which resolved with dihydroergotamine (DHE). We briefly review some of the receptor pharmacology possibly related to this observation.

Maintenance treatment with interferon for advanced ovarian cancer: results of the Northern and Yorkshire gynaecology group randomised phase III study

A randomised phase III trial was conducted to assess the role of interferon-alpha (INFalpha) 2a as maintenance therapy following surgery and/or chemotherapy in patients with epithelial ovarian carcinoma. Patients were randomised following initial surgery/chemotherapy to interferon-alpha 2a as 4.5 mega-units subcutaneously 3 days per week or to no further treatment. A total of 300 patients were randomised within the study between February 1990 and July 1997. No benefit for interferon maintenance was seen in terms of either overall or clinical event-free survival. We conclude that INF-alpha is not effective as a maintenance therapy in the management of women with ovarian cancer. The need for novel therapeutics or strategies to prevent the almost inevitable relapse of patients despite increasingly effective surgery and chemotherapy remains.

"It's as if you're locked in": qualitative explanations for area effects on smoking in disadvantaged communities

Evidence suggests that place of residence may be associated with smoking independently of individual poverty and socio-economic status. Qualitative research undertaken in disadvantaged communities in Glasgow explored possible pathways which might explain this 'area effect'. A poorly resourced and stressful environment, strong community norms, isolation from wider social norms, and limited opportunities for respite and recreation appear to combine not only to foster smoking but also to discourage or undermine cessation. Even the more positive aspects of life, such as support networks and identity, seem to encourage rather than challenge smoking. Policy and intervention responses need to tackle not only individual but also environmental disadvantage.

Automated collection of quality-of-life data: a comparison of paper and computer touch-screen questionnaires

PURPOSE

To evaluate alternative automated methods of collecting data on quality of life (QOL) in cancer patients. After initial evaluation of a range of technologies, we compared computer touch-screen questionnaires with paper questionnaires scanned by optical reading systems in terms of patients' acceptance, data quality, and reliability.

PATIENTS AND METHODS

In a randomized cross-over trial, 149 cancer patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30, version 2.0 (EORTC QLQ-C30), and the Hospital Anxiety and Depression Scale (HADS) on paper and on a touch screen. In a further test-retest study, 81 patients completed the electronic version of the questionnaires twice, with a time interval of 3 hours between questionnaires.

RESULTS

Fifty-two percent of the patients preferred the touch screen to paper; 24% had no preference. The quality of the data collected with the touch-screen system was good, with no missed responses. At the group level, the differences between scores obtained with the two modes of administration of the instruments were small, suggesting equivalence for most of the QOL scales, with the possible exception of the emotional, fatigue, and nausea/vomiting scales and the appetite item, where patients tended to give more positive responses on the touch screen. At the individual patient level, the agreement was good, with a kappa coefficient from 0.57 to 0.77 and percent global agreement from 61% to 97%. The electronic questionnaire had good test-retest reliability, with correlation coefficients between the two administrations from 0.78 to 0.95, kappa coefficients of agreement from 0.55 to 0.90, and percent global agreement from 56% to 100%.

CONCLUSION

Computer touch-screen QOL questionnaires were well accepted by cancer patients, with good data quality and reliability.

The hippocampus as a cognitive graph

A theory of cognitive mapping is developed that depends only on accepted properties of hippocampal function, namely, long-term potentiation, the place cell phenomenon, and the associative or recurrent connections made among CA3 pyramidal cells. It is proposed that the distance between the firing fields of connected pairs of CA3 place cells is encoded as synaptic resistance (reciprocal synaptic strength). The encoding occurs because pairs of cells with coincident or overlapping fields will tend to fire together in time, thereby causing a decrease in synaptic resistance via long-term potentiation; in contrast, cells with widely separated fields will tend never to fire together, causing no change or perhaps (via long-term depression) an increase in synaptic resistance. A network whose connection pattern mimics that of CA3 and whose connection weights are proportional to synaptic resistance can be formally treated as a weighted, directed graph. In such a graph, a "node" is assigned to each CA3 cell and two nodes are connected by a "directed edge" if and only if the two corresponding cells are connected by a synapse. Weighted, directed graphs can be searched for an optimal path between any pair of nodes with standard algorithms. Here, we are interested in finding the path along which the sum of the synaptic resistances from one cell to another is minimal. Since each cell is a place cell, such a path also corresponds to a path in two-dimensional space. Our basic finding is that minimizing the sum of the synaptic resistances along a path in neural space yields the shortest (optimal) path in unobstructed two-dimensional space, so long as the connectivity of the network is great enough. In addition to being able to find geodesics in unobstructed space, the same network enables solutions to the "detour" and "shortcut" problems, in which it is necessary to find an optimal path around a newly introduced barrier and to take a shorter path through a hole opened up in a preexisting barrier, respectively. We argue that the ability to solve such problems qualifies the proposed hippocampal object as a cognitive map. Graph theory thus provides a sort of existence proof demonstrating that the hippocampus contains the necessary information to function as a map, in the sense postulated by others (O'Keefe, J., and L. Nadel. 1978. The Hippocampus as a Cognitive Map. Clarendon Press, Oxford, UK). It is also possible that the cognitive mapping functions of the hippocampus are carried out by parallel graph searching algorithms implemented as neural processes. This possibility has the great attraction that the hippocampus could then operate in much the same way to find paths in general problem space; it would only be necessary for pyramidal cells to exhibit a strong nonpositional firing correlate.

Hippocampal place cells connected by Hebbian synapses can solve spatial problems

We propose that a cognitive map can be stored in the synapses between the pyramidal cells of CA3 in the form of the pattern of synaptic strengths connecting them. The model requires only that there are place cells in CA3 and that the connections between them are modifiable in a Hebbian manner. Given these suppositions, the synaptic strengths must evolve to represent the distance between firing centers of synaptically connected place cells. We argue that this arrangement of synaptic weights embodies all the formal properties of a map. We demonstrate that the information stored in such a structure is sufficient to solve several classic spatial problems including finding shortest paths, and negotiating detours. It is clear that much of the physiology and anatomy necessary to more precisely characterize the model is not known at this time. Nevertheless the model is robust under a variety of cell and connection densities. It also performs well under several different functions relating distance to synaptic strength. What is most remarkable in the model is that it is a logical consequence of the several key anatomical and physiological properties of the CA3 region of rats. Whether this information is used by the rat is difficult to assess at this time. Regardless of the outcome of this question, the model has promising applications to the field of robot navigation.

Near millimeter wave characterization of dual mode materials

Materials known to have useful properties in the IR were examined in the millimeter wave region. Their complex indices of refraction have been determined in the 90-550-GHz range. The method of determination was nondispersive Fourier transform spectroscopy. The instrument employed was a polarizing interferometer.