In situ pulmonary mucus hydration assay using rotational and translational diffusion of gold nanorods with polarization-sensitive optical coherence tomography

Significance

Assessing the nanostructure of polymer solutions and biofluids is broadly useful for understanding drug delivery and disease progression and for monitoring therapy.

Aim

Our objective is to quantify bronchial mucus solids concentration (wt. %) during hypertonic saline (HTS) treatment in vitro via nanostructurally constrained diffusion of gold nanorods (GNRs) monitored by polarization-sensitive optical coherence tomography (PS-OCT).

Approach

Using PS-OCT, we quantified GNR translational (D T ) and rotational (D R ) diffusion coefficients within polyethylene oxide solutions (0 to 3 wt. %) and human bronchial epithelial cell (hBEC) mucus (0 to 6.4 wt. %). Interpolation of D T and D R data is used to develop an assay to quantify mucus concentration. The assay is demonstrated on the mucus layer of an air-liquid interface hBEC culture during HTS treatment.

Results

In polymer solutions and mucus, D T and D R monotonically decrease with increasing concentration. D R is more sensitive than D T to changes above 1.5 wt. % of mucus and exhibits less intrasample variability. Mucus on HTS-treated hBEC cultures exhibits dynamic mixing from cilia. A region of hard-packed mucus is revealed by D R measurements.

Conclusions

The extended dynamic range afforded by simultaneous measurement of D T and D R of GNRs using PS-OCT enables resolving concentration of the bronchial mucus layer over a range from healthy to disease in depth and time during HTS treatment in vitro.

Impaired Cortico-Thalamo-Cerebellar Integration Across Schizophrenia, Bipolar II, and Attention Deficit Hyperactivity Disorder Patients Suggests Potential Neural Signatures for Psychiatric Illness

Understanding aberrant functional changes between brain regions has shown promise for characterizing and differentiating the symptoms associated with progressive psychiatric disorders. The functional integration between the thalamus and cerebellum significantly influences learning and memory in cognition. Observed in schizophrenic patients, dysfunction within the corticalthalamocerebellar (CTC) circuitry is linked to challenges in prioritizing, processing, coordinating, and responding to information. This study explored whether abnormal CTC functional network connectivity patterns are present across schizophrenia (SCHZ) patients, bipolar II disorder (BIPOL) patients, and ADHD patients by examining both task- and task-free conditions compared to healthy volunteers (HC). Leveraging fMRI data from 135 participants (39 HC, 27 SCHZ patients, 38 BIPOL patients, and 31 ADHD patients), we analyzed functional network connectivity (FNC) patterns across 115 cortical, thalamic, subcortical, and cerebellar regions of interest (ROIs). Guiding our investigation: First, do the brain regions of the CTC circuit exhibit distinct abnormal patterns at rest in SCHZ, ADHD, and BIPOL? Second, do working memory tasks in these patients engage common regions of the circuit in similar or unique patterns? Consistent with previous findings, our observations revealed FNC patterns constrained in the cerebellar, thalamic, striatal, hippocampal, medial prefrontal and insular cortices across all three psychiatric cohorts when compared to controls in both task and task-free conditions. Post hoc analysis suggested a predominance in schizophrenia and ADHD patients during rest, while the task condition demonstrated effects across all three disorders. Factor-by-covariance GLM MANOVA further specified regions associated with clinical symptoms and trait assessments. Our study provides evidence suggesting that dysfunctional CTC circuitry in both task-free and task-free conditions may be an important broader neural signature of psychiatric illness.

Multitrial free recall for evaluating memory

OBJECTIVE

Much of our knowledge concerning the neural basis of human memory derives from lab-based verbal recall tasks. Outside of the lab, clinicians use validated and normed neuropsychological tests to assess patients' memory function and to evaluate clinical interventions. Here we sought to establish the clinical validity of examining memory through multitrial free recall of semantically organized and unrelated word lists.

METHOD

We compare memory performance in multitrial free recall tasks with the Rey Auditory Verbal Learning Test and the California Verbal Learning Test, two common neuropsychological tests aimed at evaluating memory function in clinical settings. We compare predictive validity between the tasks by evaluating deficits in a patient sample and examining age-related declines in memory. We additionally compare test-retest reliability, establish convergent validity, and show the emergence of common recall dynamics between the tasks.

RESULTS

We demonstrate that both laboratory free recall tasks have better predictive validity and test-retest reliability than the established neuropsychological tests. We further show that all tasks have good convergent validity and reveal core memory processes, including temporal and semantic organization. However, we also demonstrate the benefits of repeated trials for evaluating the dynamics of memory search and their neuropsychological sequelae.

CONCLUSIONS

These results provide evidence for the clinical validity of lab-based multitrial free recall tasks and highlight their psychometric benefits over neuropsychological measures. Based on these results, we discuss the need to bridge the gap between clinical understanding of putative mechanisms underlying memory disorders and neuroscientific findings obtained using lab-based free recall tasks. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Resting-State fMRI Can Detect Alterations in Seizure Onset and Spread Regions in Patients with Non-Lesional Epilepsy: A Pilot Study

Introduction

Epilepsy is defined as non-lesional (NLE) when a lesion cannot be localized via standard neuroimaging. NLE is known to have a poor response to surgery. Stereotactic electroencephalography (sEEG) can detect functional connectivity (FC) between zones of seizure onset (OZ) and early (ESZ) and late (LSZ) spread. We examined whether resting-state fMRI (rsfMRI) can detect FC alterations in NLE to see whether noninvasive imaging techniques can localize areas of seizure propagation to potentially target for intervention.

Methods

This is a retrospective study of 8 patients with refractory NLE who underwent sEEG electrode implantation and 10 controls. The OZ, ESZ, and LSZ were identified by generating regions around sEEG contacts that recorded seizure activity. Amplitude synchronization analysis was used to detect the correlation of the OZ to the ESZ. This was also done using the OZ and ESZ of each NLE patient for each control. Patients with NLE were compared to controls individually using Wilcoxon tests and as a group using Mann-Whitney tests. Amplitude of low-frequency fluctuations (ALFF), fractional ALFF (fALFF), regional homogeneity (ReHo), degree of centrality (DoC), and voxel-mirrored homotopic connectivity (VMHC) were calculated as the difference between NLE and controls and compared between the OZ and ESZ and to zero. A general linear model was used with age as a covariate with Bonferroni correction for multiple comparisons.

Results

Five out of 8 patients with NLE showed decreased correlations from the OZ to the ESZ. Group analysis showed patients with NLE had lower connectivity with the ESZ. Patients with NLE showed higher fALFF and ReHo in the OZ but not the ESZ, and higher DoC in the OZ and ESZ. Our results indicate that patients with NLE show high levels of activity but dysfunctional connections in seizure-related areas.

Discussion

rsfMRI analysis showed decreased connectivity directly between seizure-related areas, while FC metric analysis revealed increases in local and global connectivity in seizure-related areas. FC analysis of rsfMRI can detect functional disruption that may expose the pathophysiology underlying NLE.

White Matter Network Architecture Guides Direct Electrical Stimulation through Optimal State Transitions

Optimizing direct electrical stimulation for the treatment of neurological disease remains difficult due to an incomplete understanding of its physical propagation through brain tissue. Here, we use network control theory to predict how stimulation spreads through white matter to influence spatially distributed dynamics. We test the theory’s predictions using a unique dataset comprising diffusion weighted imaging and electrocorticography in epilepsy patients undergoing grid stimulation. We find statistically significant shared variance between the predicted activity state transitions and the observed activity state transitions. We then use an optimal control framework to posit testable hypotheses regarding which brain states and structural properties will efficiently improve memory encoding when stimulated. Our work quantifies the role that white matter architecture plays in guiding the dynamics of direct electrical stimulation and offers empirical support for the utility of network control theory in explaining the brain’s response to stimulation.

Stiso et al. report evidence that network control theory can explain the propagation of electrical stimulation through the human brain and quantify how white matter connectivity is crucial for driving spatially distributed changes in activity. Furthermore, they use network control theory to predict stimulation outcome in specific cognitive contexts.

Ripple oscillations in the left temporal neocortex are associated with impaired verbal episodic memory encoding

BACKGROUND

We sought to determine if ripple oscillations (80-120 Hz), detected in intracranial electroencephalogram (iEEG) recordings of patients with epilepsy, correlate with an enhancement or disruption of verbal episodic memory encoding.

METHODS

We defined ripple and spike events in depth iEEG recordings during list learning in 107 patients with focal epilepsy. We used logistic regression models (LRMs) to investigate the relationship between the occurrence of ripple and spike events during word presentation and the odds of successful word recall following a distractor epoch and included the seizure onset zone (SOZ) as a covariate in the LRMs.

RESULTS

We detected events during 58,312 word presentation trials from 7630 unique electrode sites. The probability of ripple on spike (RonS) events was increased in the SOZ (p < 0.04). In the left temporal neocortex, RonS events during word presentation corresponded with a decrease in the odds ratio (OR) of successful recall, however, this effect only met significance in the SOZ (OR of word recall: 0.71, 95% confidence interval (CI): 0.59-0.85, n = 158 events, adaptive Hochberg, p < 0.01). Ripple on oscillation (RonO) events that occurred in the left temporal neocortex non-SOZ also correlated with decreased odds of successful recall (OR: 0.52, 95% CI: 0.34-0.80, n = 140, adaptive Hochberg, p < 0.01). Spikes and RonS that occurred during word presentation in the left middle temporal gyrus (MTG) correlated with the most significant decrease in the odds of successful recall, irrespective of the location of the SOZ (adaptive Hochberg, p < 0.01).

CONCLUSION

Ripples and spikes generated in the left temporal neocortex are associated with impaired verbal episodic memory encoding. Although physiological and pathological ripple oscillations were not distinguished during cognitive tasks, our results show an association of undifferentiated ripples with impaired encoding. The effect was sometimes specific to regions outside the SOZ, suggesting that widespread effects of epilepsy outside the SOZ may contribute to cognitive impairment.

Are on-the-day group and save samples required for elective shoulder, hip and knee arthroplasties?

INTRODUCTION

Historically, patients undergoing an elective hip, knee or shoulder arthroplasty regularly required blood transfusions. Improved surgical techniques and perioperative optimisation have significantly decreased the requirement for blood transfusions. Currently, our patients have two group and save samples taken: one six weeks preoperatively and one on admission. This study aims to determine whether a second group and save is required prior to primary elective hip, knee or shoulder arthroplasty.

METHODS

All cases of elective arthroplasty from a single centre were retrospectively analysed over a 16-month period. Each case was reviewed to determine those who had a group and save at preassessment, group and save at the time of the operation and the timing and number of blood products transfused.

RESULTS

A total of 711 elective arthroplasty procedures were completed with 48 patients requiring a transfusion during their admission. 9.9% of hip arthroplasty patients, 3.8% of knee arthroplasty patients and 4.9% of shoulder arthroplasty patients required a transfusion. The majority of the transfusions occurred at least 24 hours postoperatively with 0.84% of patients requiring an intraoperative transfusion.

DISCUSSION

The vast majority of transfusions were delivered more than 24 hours following the procedure, demonstrating that routinely cross-matched blood products are superfluous to requirements. It is our suggestion that a formal group and save be completed only if the need for a blood transfusion is formally established, leading to a significant cost saving, a reduction in clinical work load and patients having to undergo fewer procedures.

Laser interstitial thermal therapy for medically intractable mesial temporal lobe epilepsy

OBJECTIVE

To describe mesial temporal lobe ablated volumes, verbal memory, and surgical outcomes in patients with medically intractable mesial temporal lobe epilepsy (mTLE) treated with magnetic resonance imaging (MRI)-guided stereotactic laser interstitial thermal therapy (LiTT).

METHODS

We prospectively tracked seizure outcome in 20 patients at Thomas Jefferson University Hospital with drug-resistant mTLE who underwent MRI-guided LiTT from December 2011 to December 2014. Surgical outcome was assessed at 6 months, 1 year, 2 years, and at the most recent visit. Volume-based analysis of ablated mesial temporal structures was conducted in 17 patients with mesial temporal sclerosis (MTS) and results were compared between the seizure-free and not seizure-free groups.

RESULTS

Following LiTT, proportions of patients who were free of seizures impairing consciousness (including those with auras only) are as follows: 8 of 15 patients (53%, 95% confidence interval [CI] 30.1-75.2%) after 6 months, 4 of 11 patients (36.4%, 95% CI 14.9-64.8%) after 1 year, 3 of 5 patients (60%, 95% CI 22.9-88.4%) at 2-year follow-up. Median follow-up was 13.4 months after LiTT (range 1.3 months to 3.2 years). Seizure outcome after LiTT suggests an all or none response. Four patients had anterior temporal lobectomy (ATL) after LiTT; three are seizure-free. There were no differences in total ablated volume of the amygdalohippocampus complex or individual volumes of hippocampus, amygdala, entorhinal cortex, parahippocampal gyrus, and fusiform gyrus between seizure-free and non-seizure-free patients. Contextual verbal memory performance was preserved after LiTT, although decline in noncontextual memory task scores were noted.

SIGNIFICANCE

We conclude that MRI-guided stereotactic LiTT is a safe alternative to ATL in patients with medically intractable mTLE. Individualized assessment is warranted to determine whether the reduced odds of seizure freedom are worth the reduction in risk, discomfort, and recovery time. Larger prospective studies are needed to confirm our preliminary findings, and to define optimal ablation volume and ideal structures for ablation.

Predicting the laterality of temporal lobe epilepsy from PET, MRI, and DTI: A multimodal study

Pre-surgical evaluation of patients with temporal lobe epilepsy (TLE) relies on information obtained from multiple neuroimaging modalities. The relationship between modalities and their combined power in predicting the seizure focus is currently unknown. We investigated asymmetries from three different modalities, PET (glucose metabolism), MRI (cortical thickness), and diffusion tensor imaging (DTI; white matter anisotropy) in 28 left and 30 right TLE patients (LTLE and RTLE). Stepwise logistic regression models were built from each modality separately and from all three combined, while bootstrapped methods and split-sample validation verified the robustness of predictions. Among all multimodal asymmetries, three PET asymmetries formed the best predictive model (100% success in full sample, >95% success in split-sample validation). The combinations of PET with other modalities did not perform better than PET alone. Probabilistic classifications were obtained for new clinical cases, which showed correct lateralization for 7/7 new TLE patients (100%) and for 4/5 operated patients with discordant or non-informative PET reports (80%). Metabolism showed closer relationship with white matter in LTLE and closer relationship with gray matter in RTLE. Our data suggest that metabolism is a powerful modality that can predict seizure laterality with high accuracy, and offers high value for automated predictive models. The side of epileptogenic focus can affect the relationship of metabolism with brain structure. The data and tools necessary to obtain classifications for new TLE patients are made publicly available.

Increased microstructural white matter correlations in left, but not right, temporal lobe epilepsy

Microstructural white matter tract correlations have been shown to reflect known patterns of phylogenetic development and functional specialization in healthy subjects. The aim of this study was to establish intertract correlations in a group of controls and to examine potential deviations from normality in temporal lobe epilepsy (TLE). We investigated intertract correlations in 28 healthy controls, 21 left TLE (LTLE) and 23 right TLE (RTLE). Nine tracts were investigated, comprising the parahippocampal fasciculi, the uncinate fasciculi, the arcuate fasciculi, the frontoparietal tracts, and the fornix. An abnormal increase in tract correlations was observed in LTLE, while RTLE showed intertract correlations similar to controls. In the control group, tract correlations increased with increasing fractional anisotropy (FA), while in the TLE groups tract correlations increased with decreasing FA. Cluster analyses revealed agglomeration of bilateral pairs of homologous tracts in healthy subjects, with such pairs separated in our LTLE and RTLE groups. Discriminant analyses aimed at distinguishing LTLE from RTLE, revealing that tract correlations produce higher rates of accurate group classification than FA values. Our results confirm and extend previous work by showing that LTLE compared to RTLE patients display not only more extensive losses in microstructural orientation but also more aberrant intertract correlations. Aberrant correlations may be related to pathologic processes (i.e., seizure spread) or to adaptive processes aimed at preserving key cognitive functions. Our data suggest that tract correlations may have predictive value in distinguishing LTLE from RTLE, potentially moving diffusion imaging to a place of greater prominence in clinical practice.

Distinct types of white matter changes are observed after anterior temporal lobectomy in epilepsy

Anterior temporal lobectomy (ATL) is commonly adopted to control medically intractable temporal lobe epilepsy (TLE). Depending on the side of resection, the degree to which Wallerian degeneration and adaptive plasticity occur after ATL has important implications for understanding cognitive and clinical outcome. We obtained diffusion tensor imaging from 24 TLE patients (12 left) before and after surgery, and 12 matched controls at comparable time intervals. Voxel-based analyses were performed on fractional anisotropy (FA) before and after surgery. Areas with postoperative FA increase were further investigated to distinguish between genuine plasticity and processes related to the degeneration of crossing fibers. Before surgery, both patient groups showed bilateral reduced FA in numerous tracts, but left TLE patients showed more extensive effects, including language tracts in the contralateral hemisphere (superior longitudinal fasciculus and uncinate). After surgery, FA decreased ipsilaterally in both ATL groups, affecting the fornix, uncinate, stria terminalis, and corpus callosum. FA increased ipsilaterally along the superior corona radiata in both left and right ATL groups, exceeding normal FA values. In these clusters, the mode of anisotropy increased as well, confirming fiber degeneration in an area with crossing fibers. In left ATL patients, pre-existing low FA values in right superior longitudinal and uncinate fasciculi normalized after surgery, while MO values did not change. Preoperative verbal fluency correlated with FA values in all areas that later increased FA in left TLE patients, but postoperative verbal fluency correlated only with FA of the right superior longitudinal fasciculus. Our results demonstrate that genuine reorganization occurs in non-dominant language tracts after dominant hemisphere resection, a process that may help implement the inter-hemispheric shift of language activation found in fMRI studies. The results indicate that left TLE patients, despite showing more initial white matter damage, have the potential for greater adaptive changes postoperatively than right TLE patients.

Contralateral interictal spikes are related to tapetum damage in left temporal lobe epilepsy

OBJECTIVE

In temporal lobe epilepsy (TLE), the epileptogenic focus is focal and unilateral in the majority of patients. A key characteristic of focal TLE is the presence of subclinical epileptiform activity in both the ictal and contralateral "healthy" hemisphere. Such interictal activity is clinically important, as it may reflect the spread of pathology, potentially leading to secondary epileptogenesis. The role played by white matter pathways in this process is unknown.

METHODS

We compared three interhemispheric white matter tracts (anterior commissure, fornix, and tapetum) to determine the pathway most associated with the presence of contralateral interictal spikes. Forty patients with unilateral left or right TLE were categorized based on the presence or absence of contralateral interictal spikes. Analyses of variance (ANOVAs) were run on diffusion properties from each tract.

RESULTS

The analyses revealed that patients with left TLE and with bilateral interictal spikes had lower fractional anisotropy (FA) and higher mean diffusivity (MD) in the tapetum. Patients with right TLE did not show this effect. No significant associations with bilateral activity were observed for the other tracts. Blood oxygen level-dependent (BOLD) functional connectivity data revealed that homotopic lateral, not mesial, temporal areas were reliably correlated in bilateral patients, independent of ictal side.

SIGNIFICANCE

Our results indicate that, among the tracts investigated, only the tapetum was associated with contralateral epileptiform activity, implicating this structure in seizures and possible secondary epileptogenesis. We describe two mechanisms that might explain this association (the interruption of inhibitory signals or the toxic effect of carrying epileptiform signals toward the healthy hemisphere), but also acknowledge other rival factors that may be at work. We also report that patients with TLE with bilateral spikes had increased lateral bitemporal lobe connectivity. Our current results can be seen as bringing together important functional and structural data to elucidate the basis of contralateral interictal activity in focal, unilateral epilepsy. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Influence of anxiety on memory performance in temporal lobe epilepsy

This study examined the degree to which anxiety contributed to inconsistent material-specific memory difficulties among 243 patients with temporal lobe epilepsy from the Multisite Epilepsy Study. Visual memory performance on the Rey Complex Figure Test (RCFT) was poorer for those with high versus low levels of anxiety but was not found to be related to the TLE side. The verbal memory score on the California Verbal Learning Test (CVLT) was significantly lower for patients with left-sided TLE than for patients with right-sided TLE with low anxiety levels but equally impaired for those with high anxiety levels. These results suggest that we can place more confidence in the ability of verbal memory tests like the CVLT to lateralize to left-sided TLE for those with low anxiety levels, but that verbal memory will be less likely to produce lateralizing information for those with high anxiety levels. This suggests that more caution is needed when interpreting verbal memory tests for those with high anxiety levels. These results indicated that RCFT performance was significantly affected by anxiety and did not lateralize to either side, regardless of anxiety levels. This study adds to the existing literature which suggests that drawing-based visual memory tests do not lateralize among patients with TLE, regardless of anxiety levels.

Pharmacokinetics and safety of subcutaneous immune globulin (human), 10% caprylate/chromatography purified in patients with primary immunodeficiency disease

Subcutaneous administration of intravenous immunoglobulin G (IgG) preparations provides an additional level of patient convenience and more options for patients with poor venous access or a history of intravenous IgG reactions. An open-label, pharmacokinetic trial (n = 32) determined the non-inferiority of the subcutaneous versus intravenous route of 10% caprylate/chromatography purified human immune globulin intravenous (IGIV-C; Gamunex®) administration by comparing the steady-state area under the concentration-versus-time curve (AUC) of total plasma IgG in patients with primary immunodeficiency disease. Patients on stable IGIV-C received two intravenous infusions (administered 3 or 4 weeks apart). Seven to 10 days after the second intravenous infusion, all patients switched to a weekly infusion of subcutaneous IGIV-C, with the dose equal to 137% of the previous weekly equivalent intravenous dose, for up to 24 weeks. Samples for pharmacokinetic analysis were collected during steady state for intravenous and subcutaneous IGIV-C treatments. The AUC(0-) τ geometric least-squares mean ratio was 0·89 (90% confidence interval, 0·86-0·92) and met the criteria for non-inferiority. The overall mean steady-state trough concentration of plasma total IgG with subcutaneous IGIV-C was 11·4 mg/ml, 18·8% higher than intravenous IGIV-C (9·6 mg/ml). Subcutaneous IGIV-C was safe and well tolerated. Subcutaneous IGIV-C infusion-site reactions were generally mild/moderate and the incidence decreased over time. No serious bacterial infections were reported. Weekly subcutaneous IGIV-C infusion using 137% of the weekly equivalent intravenous immunoglobulin dose provides an AUC comparable to intravenous administration, thus allowing patients to maintain the same IgG preparation/formulation if switching between intravenous and subcutaneous infusions.

A test of the role of the medial temporal lobe in single-word decoding

The degree to which the MTL system contributes to effective language skills is not well delineated. We sought to determine if the MTL plays a role in single-word decoding in healthy, normal skilled readers. The experiment follows from the implications of the dual-process model of single-word decoding, which provides distinct predictions about the nature of MTL involvement. The paradigm utilized word (regular and irregularly spelled words) and pseudoword (phonetically regular) stimuli that differed in their demand for non-lexical as opposed lexical decoding. The data clearly showed that the MTL system was not involved in single word decoding in skilled, native English readers. Neither the hippocampus nor the MTL system as a whole showed significant activation during lexical or non-lexical based decoding. The results provide evidence that lexical and non-lexical decoding are implemented by distinct but overlapping neuroanatomical networks. Non-lexical decoding appeared most uniquely associated with cuneus and fusiform gyrus activation biased toward the left hemisphere. In contrast, lexical decoding appeared associated with right middle frontal and supramarginal, and bilateral cerebellar activation. Both these decoding operations appeared in the context of a shared widespread network of activations including bilateral occipital cortex and superior frontal regions. These activations suggest that the absence of MTL involvement in either lexical or non-lexical decoding appears likely a function of the skilled reading ability of our sample such that whole-word recognition and retrieval processes do not utilize the declarative memory system, in the case of lexical decoding, and require only minimal analysis and recombination of the phonetic elements of a word, in the case of non-lexical decoding.

Critical steps to scaling telehealth for national reform

Telehealth services show great promise to expand access to care while improving patient safety and reducing costs of care for all Americans. The expansion of telehealth has been slowed by a host of factors, including limited reimbursement, legal and regulatory barriers, limited provider capacity, and a lack of general public knowledge and/or acceptance of telehealth technologies and services. To hasten the expansion of telehealth requires a multifaceted and coordinated approach that will include healthcare professionals, regulators, payers, lawmakers, and patients. This paper will outline the steps necessary to scale telehealth services to a level that will help to address issues such as access to care, patient safety, quality, provider shortages, licensure and preparedness, all important elements of healthcare reform.

A dissociation between implicit and explicit verbal memory in left temporal lobe epilepsy

PURPOSE

Temporal lobe epilepsy patients are well known to present deficits on explicit verbal memory procedures (e.g., recall, recognition). The integrity of implicit memory procedures in these patients is not established. Previous studies in this area used implicit memory measures contaminated by the effects of explicit memory.

METHODS

We examined the integrity of verbal implicit and explicit memory in left temporal lobe epilepsy (LTLE) patients and hypothesized that a clear dissociation in performance would be found with a relative preservation of implicit memory. TLE patients (n = 15) and age- and education-matched healthy normal patients (n = 15) were shown a 40-word study list, followed by a test phase requiring completion of word stems based on the study words or new/unseen words. Experimental conditions involved instructions to provide either the old (study) words or novel/nonlist words when completing the stem. Measures of automaticity and recollection provided uncontaminated indices of implicit and explicit memory, respectively.

RESULTS

The data showed a significant difference (p < 0.001) between the patients (Recollection, 0.12; SD, 0.18) and controls (0.50, SD, 0.15) on the measure of explicit memory. In contrast, the patients (Automaticity, 0.51; SD, 0.11) and controls (0.45, SD, 0.18) performed similarly on the implicit memory measure, with patient scores clearly at normative levels based on other Process Dissociation Procedure data.

CONCLUSIONS

The data demonstrate the integrity of implicit memory in LTLE patients. Finding a dissociation between the two forms of verbal memory in LTLE patients provides evidence that they rely on different neuroanatomic systems.

Regional brain activation associated with different performance patterns during learning of a complex motor skill

In understanding the brain's response to extensive practice and development of high-level, expert skill, a key question is whether the same brain structures remain involved throughout the different stages of learning and a form of adaptation occurs, or a new functional circuit is formed with some structures dropping off and others joining. After training subjects on a set of complex motor tasks (tying knots), we utilized fMRI to observe that in subjects who learned the task well new regional activity emerged in posterior medial structures, i.e. the posterior cingulate gyrus. Activation associated with weak learning of the knots involved areas that mediate visual spatial computations. Brain activity associated with no substantive learning indicated involvement of areas dedicated to the declarative aspects learning such as the anterior cingulate and prefrontal cortex. The new activation for the pattern of strong learning has alternate interpretations involving either retrieval during episodic memory or a shift toward non-executive cognitive control of the task. While these interpretations are not resolved, the study makes clear that single time-point images of motor skill can be misleading because the brain structures that implement action can change following practice.

The brain's response to incidental intruded words during focal text processing

The functional neuroanatomy associated with processing single words incidentally, outside focal attention, was investigated. We asked subjects (n = 15) to listen, focus on, and comprehend a story narrative, and then single, unrelated but meaningful words were intruded into the ongoing narrative. We also manipulated the type of intruded word, using either neutral or emotionally valent words, to evaluate the extent of semantic processing and a potential encoding advantage for one type of material. Analyses emphasized the areas of activation unique to the intruded words as distinguished from the narrative text. Subjects were normal, healthy adults (n = 15). Compared to narrative text, the intruded words were associated with activation in the right middle temporal gyrus (BA 39) and posterior cingulate/precuneus regions (BA 30, 23). We conclude that the intruded words did make contact with word-level lexical but not necessarily semantic structures in the middle temporal region. The data suggested that the intruded words were processed by a "nonexecutive" monitoring system implemented by a pairing of activation in posterior, medial structures such as the posterior cingulate with deactivation in brain stem structures. This pattern induced a shift to more passive, less effortful, nonstrategic monitoring of the words. Thus, attention processing, not semantic processing, changes best characterized the brain activation unique to the intruded words. This posterior, medial region is discussed as a substrate dedicated to processing a second, incidental stream of information and thereby providing a crucial mechanism for implementing dual processing of the kind examined here.

Polydipsia and schizophrenia in a psychiatric hospital: a replication study

A prior study in a US state hospital suggested that schizophrenia, smoking and long hospitalization were associated with polydipsia. This study, in another US hospital, attempts to (1) replicate that schizophrenia and smoking are associated with polydipsia, and (2) rule out that this relationship is partly explained by alcohol and drug use. Both studies have similar methodologies. The second sample included 588 inpatients. Models of variables associated with polydipsia were developed using logistic regression. In the second study, after correcting for other factors, the association between polydipsia and schizophrenia showed a borderline significance, while polydipsia and smoking displayed a significant association. Neither organic brain lesions, nor alcohol or drug use, were associated with polydipsia. An analysis combining both samples showed that: (1) schizophrenia, long hospitalization, smoking and heavy smoking were significantly associated with polydipsia, and (2) male gender and Caucasian race (but not smoking) increased the risk of developing water intoxication in polydipsic patients. These two studies in severely mentally ill patients suggest that the association of polydipsia with schizophrenia, smoking and chronicity is consistent and independent from the definition of polydipsia (by staff, a biological method or the combination of both). Psychiatric medications do not appear to explain most cases of polydipsia in these patients.

Schizophrenia and tobacco smoking: a replication study in another US psychiatric hospital

A prior study in a US state hospital suggested that schizophrenia is more closely associated with tobacco smoking when compared with other severe mental illnesses. This second study, in a neighborhood hospital, tries to (1) replicate that schizophrenia is associated with smoking and heavy smoking, and (2) rule out that this relationship is explained by substance use. The methodology was very similar to the first study. The sample included 588 inpatients. Logistic regression was used to develop models of variables associated with smoking or heavy smoking. The frequency of current smoking for the total, schizophrenic and non-schizophrenic samples were respectively 71, 75, and 55%. The sequence of frequencies from the highest to lowest was the same as in the first study: male schizophrenic patients, male non-schizophrenic patients, female schizophrenic patients and female non-schizophrenic patients. This second study consistently replicated the relationship between schizophrenia and smoking (after correcting for other variables) including history of alcohol and drug abuse or dependence. Only one of two definitions of heavy smoking showed a significant association with schizophrenia. In summary, these two studies suggest that schizophrenia is strongly associated with smoking. Neither substance use, antipsychotics, nor institutionalism can explain this relationship.

Using telemedicine to avoid transfer of rural emergency department patients

Access to emergency treatment in rural areas can often mean the difference between life and death. Telemedicine technologies have the potential of providing earlier diagnosis and intervention, of saving lives and of avoiding unnecessary transfers from rural hospital emergency departments to urban hospitals. This study examined the hypothetical impact of telemedicine services on patients served by the emergency departments of two rural Missouri hospitals and the potential financial impact on the affected hospitals. Of the 246 patients transferred to the hub hospital from the two facilities during 1996, 161 medical records (65.4 percent) were analyzed. Using a conservative approach, only 12 of these cases were identified as potentially avoidable transfers with the use of telemedicine. Of these 12, 5 were admitted to the hub hospital after transfer. In addition to this conservative estimate of avoidable transfers based on current availability of resources in the rural hospitals, two more aggressive scenarios were developed, based on an assumption of increased service availability in the rural hospitals. Economic multipliers were used to estimate the financial impacts on communities in each scenario. This evaluation study demonstrates the potential value of telemedicine use in rural emergency departments to patients, rural hospitals and rural communities.

An evaluation of satisfaction with telemedicine among health-care professionals

A survey was conducted among non-doctor health-care professionals in six rural counties in Missouri. The purpose of the survey was to establish baseline data to evaluate the effect of changes in the health-care sector, especially technology changes, on the job satisfaction, career satisfaction, relationships and communication activities of health professionals. The survey included three rural counties in which integrated telecommunication and interactive video telemedicine services were being installed, but before significant activities had begun, and three comparator counties without substantial integrated telecommunications infrastructure and telemedicine services. During a one-month study period, 1108 questionnaires were distributed. The total response rate was 50.1% (n = 555). Of the respondents, 30.3% indicated that technology in health-care was having a large effect on their work, although only 18.2% indicated that telemedicine and telecommunications were having a large effect. No systematic differences were found among the health professionals in the two communities at the time telemedicine equipment was being installed.

Hope and anxiety of individual family members of critically ill adults

This correlational study describes levels of hope and states of anxiety of individual family members of critically ill patients and investigates the relationship between hope and state of anxiety. Forty-four family members of critically ill patients participated in the study and revealed a high level of hope and a high level of anxiety within 72 hours of the patient's hospitalization, regardless of personal or situational characteristics. Hope and anxiety were not significantly related in this sample; themes of hope focused on past and present experiences, whereas anxiety centered on death of the loved one. Participants looked to the past, recalling happy times, and to the future, in relation to goals and potential. Family members acknowledged feeling secure, self-confident, and steady, and were able to make decisions because they were not confused about the situation. Nurses are challenged to inspire the family's hope and decrease their anxiety.

Cross-education of muscle strength is greater with stimulated than voluntary contractions

Cross-education enhances the performance of muscles not directly involved in the chronic conditioning of the muscles in a remote limb. Substantial cross-education occurs after training with eccentric contractions or with contractions evoked by electromyostimulation (EMS). Since during EMS and eccentric contractions, skin and muscle afferents are activated that have excitatory effects on contralateral homologous muscles, it was hypothesized that exercise training with stimulated vs. voluntary eccentric contractions would lead to greater cross-education. Thirty-two women were randomly assigned to a voluntary (Vol), an EMS, or remote EMS (rEMS) exercise group and performed 840 voluntary or stimulated eccentric contractions over 6 weeks. All subjects, including nonexercising controls (Con), were tested pre- and posttraining for maximal voluntary and stimulated isometric and eccentric quadriceps strength. Ipsilateral voluntary and stimulated forces increased in all groups. Changes in EMG activity paralleled those in voluntary force in each limb. No changes occurred in grip strength. The great contra- and ipsilateral strength gains after EMS training were most likely related to an additive effect of EMS and muscle lengthening.

Education for children with disabilities: the rationale for inclusion

OBJECTIVE

To discuss issues in the education of children with disabilities, particularly with respect to inclusion in mainstream classes.

METHODOLOGY

Review of the literature on education for children with disabilities, focusing on the inclusion versus segregation debate.

RESULTS

The literature provides no support for segregation and some support for the view that segregated children are disadvantaged. What seems to be important is the way the child is educated rather than where the education takes place. In addition, there are ethical, sociological, and legal arguments in favour of an inclusive educational system.

CONCLUSIONS

There are good arguments to encourage inclusive education for children with disabilities. In advising parents, doctors should focus on how rather than where the child with a disability should be educated.

The roles of the bacteriophage T4 r genes in lysis inhibition and fine-structure genetics: a new perspective

Seldom has the study of a set of genes contributed more to our understanding of molecular genetics than has the characterization of the rapid-lysis genes of bacteriophage T4. For example, T4 rII mutants were used to define gene structure and mutagen effects at the molecular level and to help unravel the genetic code. The large-plaque morphology of these mutants reflects a block in expressing lysis inhibition (LIN), the ability to delay lysis for several hours in response to sensing external related phages attacking the cell, which is a unique and highly adaptive attribute of the T4 family of phages. However, surprisingly little is known about the mechanism of LIN, or how the various r genes affect its expression. Here, we review the extensive old literature about the r genes and the lysis process and try to sort out the major players affecting lysis inhibition. We confirm that superinfection can induce lysis inhibition even while infected cells are lysing, suggesting that the signal response is virtually instantaneous and thus probably the result of post-translational regulation. We identify the rI gene as ORF tk.-2, based on sequence analysis of canonical rI mutants. The rI gene encodes a peptide of 97 amino acids (Mr = 11.1 kD; pI = 4.8) that probably is secreted into the periplasmic space. This gene is widely conserved among T-even phage. We then present a model for LIN, postulating that rI is largely responsible for regulating the gpt holin protein in response to superinfection. The evidence suggests that the rIIA and B genes are not directly involved in lysis inhibition; rather, when they are absent, an alternate pathway for lysis develops which depends on the presence of genes from any of several possible prophages and is not sensitive to lysis inhibition.

Normal forces and myofibrillar disruption after repeated eccentric exercise

To investigate the "rapid-adaptation" phenomenon, we examined force, neural, and morphological adaptations in 12 subjects who performed 100 eccentric contractions with the quadriceps muscle (bout 1) and repeated the same exercise after a 2-wk hiatus (bout 2). Two days after bout 1, quadriceps muscle strength and surface electromyographic (EMG) activity declined approximately 37 and 28%, respectively, in the control group (n = 6). At day 2 after bout 1, significant increases occurred in patellar tendon reflex amplitude (approximately 25%), muscle soreness (fivefold), and serum creatine kinase (220%), and 65 +/- 12% of the total number of pixels in the EMG indicated myofibrillar disruption. At day 7 after bout 1, all variables returned to normal. At day 2 after bout 2, no significant changes occurred in force, EMG, creatine kinase, or soreness, but reflex amplitude increased, and 23 +/- 4% of the total number of pixels in the EMG still indicated myofibrillar disruption. The results suggest that the rapid force recovery following eccentric exercise is mediated at least in part by neural factors and that this recovery may occur independently of cell disruption.

The importance of smoking education and preventative health strategies for people with intellectual disability

Tobacco smoking is a major health problem within our community. To date, little attention has been focused on determining the prevalence of smoking in people with disabilities or in developing appropriate strategies to assist them to stop smoking. Funding from the Victorian Health Promotion Foundation enabled the Developmental Disability Unit at Monash University, Box Hill, Victoria, Australia, to undertake a project investigating smoking in a population of people with intellectual disability. In the first part of the project, the smoking rate among a geographically defined group of people with mild intellectual disability was investigated. A smoking prevalence of 36% was found within the sample group, as compared to a prevalence of 26% within the general Victorian adult population. An association was found between the motivation to quite and the recall of advice to stop smoking. The second part of the project comprised the development and piloting of a smoking education course for people with intellectual disability. The pilot sample was small, but the results were encouraging. Fifty-five per cent of the group either quit smoking or cut down their intake significantly. Seventy-three per cent expressed a desire to stop smoking at the completion of the course, and all participants expressed an increased concern and knowledge about the effects of smoking on their health after completing the course.

Prevalence of adult diabetes in Ibadan, Nigeria

Within the framework of an international collaborative network, we measured the prevalence of diabetes mellitus in a traditional Yoruba community in the city of Ibadan, Nigeria. Using a random sampling technique we enrolled a community sample of 247 men and women. Fasting blood glucose (FBG) was measured at the community clinic from a fingerstick using the Companion2 Medisense blood glucose meter. The mean FBG was 4.7 mmol/L and 4.9 mmol/L for men and women, respectively. Using the 1985 WHO criteria, the prevalence of diabetes was 2.8%. There was no significant rise in FBG with age. Compared to the lowest quartile of the body mass index (BMI), there was about a 1.5 fold increased risk of developing elevated FBG. The test of trend between FBG and BMI was however not statistically significant. Despite a modest hypertension rate (22.3%), there was no significant difference in the FBG for hypertensives compared to normotensives. The findings of this study show that the prevalence of diabetes mellitus in this West African community remains low compared to nations in Western societies. However, in comparison to previous estimates from sub-Saharan Africa, the prevalence of adult onset diabetes seems to be on the increase.

Performance on the Purdue pegboard and finger tapping by schizophrenics after mellow and frenetic antecedent music

Effects of musical selections on motor performance have been inconsistent. Using a 3-factor within-subjects design [mellow music (4:4 time), frenetic music (2:8 time), and white noise conditions], each of 34 schizophrenic inpatients volunteered to perform the Purdue Pegboard and Finger Oscillation (Tapping) following 1-min. counterbalanced presentations of three types of music. Both pegboard and tapping performance were higher after frenetic music but unaffected by mellow music.

Outcome measures of a chronic pain program: a prospective statistical study

OBJECTIVE

To provide outcome data measuring objective and subjective variables of an individualized, multidisciplinary, comprehensive pain management program.

DESIGN

The study is a prospective evaluation of 50 consecutive patients who completed the pain management program. Objective measures were medication use and return to work. Subjective measures included self-reports of pain levels and completion of a Personal Concerns and Goals Assessment (PCGA) examining issues of lifestyle and emotional well-being. These measures were compared at program onset and completion by using appropriate statistical analyses.

RESULTS

Objective measures: Medication use by the study subjects decreased overall by 72% within all drug categories. Opioid use was eliminated. Regarding return to work, the study subjects increased their work hours by twofold overall. Of patients working fewer than 30 h per week at program onset, representing 62% of the study population, a fivefold return to work was observed. Subjective measures: Overall pain levels improved by 33%, with an 18 to 47% improvement in all descriptors (average pain levels on good or bad days, average number of good or bad days). Of the PCGA factors, patients improved 24 to 46% in all categories concerning lifestyle and emotional well-being. Correlative analysis of the data produced prognostic information as well as insights into chronic pain development.

CONCLUSIONS

This study of objective and subjective outcome measures demonstrates that a comprehensive program employing specific principles and methods produces an effective approach for the management of chronic pain. Patients disabled by chronic pain regain a quality of life that allows them to resume a functioning, productive role.