Methods for Neuroscience Drug Development: Guidance on Standardization of the Process for Defining Clinical Outcome Strategies in Clinical Trials

Neurosciences clinical trials continue to have notoriously high failure rates. Appropriate outcomes selection in early clinical trials is key to maximizing the likelihood of identifying new treatments in psychiatry and neurology. The field lacks good standards for designing outcome strategies, therefore The Outcomes Research Group was formed to develop and promote good practices in outcome selection. This article describes the first published guidance on the standardization of the process for clinical outcomes in neuroscience. A minimal step process is defined starting as early as possible, covering key activities for evidence generation in support of content validity, patient-centricity, validity requirements and considerations for regulatory acceptance. Feedback from expert members is provided, regarding the risks of shortening the process and examples supporting the recommended process are summarized. This methodology is now available to researchers in industry, academia or clinics aiming to implement consensus-based standard practices for clinical outcome selection, contributing to maximizing the efficiency of clinical research.

Sensitivity of Individual and Composite Test Scores from the Cogstate Brief Battery to Mild Cognitive Impairment and Dementia Due to Alzheimer's Disease

BACKGROUND

The Cogstate Brief Battery (CBB) is a computerized cognitive test battery used commonly to identify cognitive deficits related to Alzheimer's disease (AD). However, AD and normative samples used to understand the sensitivity of the CBB to AD in the clinic have been limited, as have the outcome measures studied.

OBJECTIVE

This study investigated the sensitivity of CBB outcomes, including potential composite scores, to cognitive impairment in mild cognitive impairment (MCI) and dementia due to AD, in carefully selected samples.

METHODS

Samples consisted of 4,871 cognitively unimpaired adults and 184 adults who met clinical criteria for MCI (Clinical Dementia Rating (CDR) = 0.5) or dementia (CDR > 0.5) due to AD and CBB naive. Speed and accuracy measures from each test were examined, and theoretically- and statistically-derived composites were created. Sensitivity and specificity of classification of cognitive impairment were compared between outcomes.

RESULTS

Individual CBB measures of learning and working memory showed high discriminability for AD-related cognitive impairment for CDR 0.5 (AUCs ∼ 0.79-0.88), and CDR > 0.5 (AUCs ∼ 0.89-0.96) groups. Discrimination ability for theoretically derived CBB composite measures was high, particularly for the Learning and Working Memory (LWM) composite (CDR 0.5 AUC = 0.90, CDR > 0.5 AUC = 0.97). As expected, statistically optimized linear composite measures showed strong discrimination abilities albeit similar to the LWM composite.

CONCLUSIONS

In older adults, the CBB is effective for discriminating cognitive impairment due to MCI or AD-dementia from unimpaired cognition with the LWM composite providing the strongest sensitivity.

Clinically Relevant Changes for Cognitive Outcomes in Preclinical and Prodromal Cognitive Stages: Implications for Clinical Alzheimer Trials

BACKGROUND AND OBJECTIVES

Identifying a clinically meaningful change in cognitive test score is essential when using cognition as an outcome in clinical trials. This is especially relevant because clinical trials increasingly feature novel composites of cognitive tests. Our primary objective was to establish minimal clinically important differences (MCIDs) for commonly used cognitive tests, using anchor-based and distribution-based methods, and our secondary objective was to investigate a composite cognitive measure that best predicts a minimal change in the Clinical Dementia Rating-Sum of Boxes (CDR-SB).

METHODS

From the Swedish BioFINDER cohort study, we consecutively included cognitively unimpaired (CU) individuals with and without subjective or mild cognitive impairment (MCI). We calculated MCIDs associated with a change of ≥0.5 or ≥1.0 on CDR-SB for Mini-Mental State Examination (MMSE), ADAS-Cog delayed recall 10-word list, Stroop, Letter S Fluency, Animal Fluency, Symbol Digit Modalities Test (SDMT) and Trailmaking Test (TMT) A and B, and triangulated MCIDs for clinical use for CU, MCI, and amyloid-positive CU participants. For investigating cognitive measures that best predict a change in CDR-SB of ≥0.5 or ≥1.0 point, we conducted receiver operating characteristic analyses.

RESULTS

Our study included 451 cognitively unimpaired individuals, 90 with subjective cognitive decline and 361 without symptoms of cognitive decline (pooled mean follow-up time 32.4 months, SD 26.8, range 12-96 months), and 292 people with MCI (pooled mean follow-up time 19.2 months, SD 19.0, range 12-72 months). We identified potential triangulated MCIDs (cognitively unimpaired; MCI) on a range of cognitive test outcomes: MMSE -1.5, -1.7; ADAS delayed recall 1.4, 1.1; Stroop 5.5, 9.3; Animal Fluency: -2.8, -2.9; Letter S Fluency -2.9, -1.8; SDMT: -3.5, -3.8; TMT A 11.7, 13.0; and TMT B 24.4, 20.1. For amyloid-positive CU, we found the best predicting composite cognitive measure included gender and changes in ADAS delayed recall, MMSE, SDMT, and TMT B. This produced an AUC of 0.87 (95% CI 0.79-0.94, sensitivity 75%, specificity 88%).

DISCUSSION

Our MCIDs may be applied in clinical practice or clinical trials for identifying whether a clinically relevant change has occurred. The composite measure can be useful as a clinically relevant cognitive test outcome in preclinical AD trials.

ACU193, a Monoclonal Antibody that Selectively Binds Soluble Aß Oligomers: Development Rationale, Phase 1 Trial Design, and Clinical Development Plan

BACKGROUND

Alzheimer's disease is a large and growing unmet medical need. Clinical trial designs need to assess disease-related outcomes earlier to accelerate the development of better treatments for Alzheimer's disease. ACU193 is a monoclonal antibody that selectively targets amyloid β oligomers, thought to be the most toxic species of Aβ that accumulates early in AD and contributes to downstream pathological effects. Nonclinical data indicate that ACU193 can reduce the toxic effects of amyloid β oligomers. ACU193 is currently being investigated in a phase 1 clinical trial designed with the properties described in this report. This phase 1 trial is designed to provide data to enable a go/no-go decision regarding the initiation of a subsequent phase 2/3 study.

OBJECTIVES

To design a phase 1 study that assesses target engagement and incorporates novel measures to support more rapid development of a potential disease-modifying treatment for Alzheimer's disease.

DESIGN

The INTERCEPT-AD trial for ACU193 is an ongoing randomized, placebo-controlled phase 1a/b study that assesses safety, tolerability, pharmacokinetics, target engagement, clinical measures, and several Alzheimer's disease biomarkers, including novel digital and imaging biomarkers.

SETTING

For INTERCEPT-AD, brief inpatient stays for patients in the single ascending dose portion of the study, with the remainder of the evaluations being performed as outpatients at multiple clinical trial sites in the U.S.

PARTICIPANTS

Patients with early Alzheimer's disease (mild cognitive impairment or mild dementia with a positive florbetapir positron emission tomography scan).

INTERVENTION

ACU193 administered intravenously at doses of 2- 60 mg/kg.

MEASUREMENTS

Safety assessments including magnetic resonance imaging for the presence of amyloid-related imaging abnormalities, clinical assessments for Alzheimer's disease including the Alzheimer's Disease Rating Scale-cognition and Clinical Dementia Rating scale, pharmacokinetics, a measure of target engagement, and digital and imaging biomarkers, including a computerized cognitive test battery and a measure of cerebral blood flow using arterial spin labelling magnetic resonance imaging.

RESULTS

A phase 1 study design was developed for ACU193 that allows collection of data that will enable a go/no-go decision for initiation of a subsequent adaptive phase 2/3 study.

CONCLUSIONS

A phase 1a/b trial and an overall clinical development plan for an Alzheimer's disease treatment can be designed that maintains patient safety, allows informed decision-making, and achieves an accelerated timeline by using novel biomarkers and adaptive study designs.

Psychometric Properties of the Clinical Dementia Rating - Sum of Boxes and Other Cognitive and Functional Outcomes in a Prodromal Alzheimer's Disease Population

BACKGROUND

The Clinical Dementia Rating-Sum of Boxes (CDR-SB) has been proposed as a primary outcome for use in prodromal AD trials. However, the psychometric properties of this, and of other commonly used measures, have not been well-established in this patient population.

OBJECTIVE

To describe the psychometric properties of commonly used efficacy measures in a clinical trial of prodromal AD.

SETTING

Data were gathered as part of a two-year clinical trial.

PARTICIPANTS

Patients had biomarker confirmed prodromal AD.

MEASUREMENTS

Clinical Dementia Rating (CDR), Functional Activities Questionnaire (FAQ), Alzheimer's Disease Assessment Scale - Cognition Subscale 11 and 13 (ADAS-Cog), Mini Mental State Exam (MMSE), and Free and Cued Selective Reminding Test (FCSRT-IR [words]). Assessments were conducted at least every 24 weeks.

RESULTS

For the CDR-SB, test-retest reliability was good (intra-class correlation coefficient [ICC]=0.83); internal consistency was 0.65 at baseline but above 0.8 at later assessments. Relationships between the CDR-SB and other measures were as expected (higher correlations with more closely related constructs), and the CDR-SB differentiated between patients with different severities of dementia (-2.9 points difference between CDR-Global Score 0.5 and 1, P<.0001). Floor and ceiling effects on the CDR-SB total score were minimal; however, at baseline there were ceiling effects in the personal care domain. Further detail is provided on the psychometric properties of ADAS-Cog, MMSE, FCSRT-IR and FAQ in this population.

CONCLUSION

The psychometric properties of the CDR-SB are adequate in prodromal AD and continued use is warranted in clinical trials. However, there remains scope for improvement in the assessment of functional constructs and development of novel measures should continue.

A portable miniaturized laser heterodyne radiometer (mini‑LHR) for remote measurements of column CH4 and CO2

We present the design of a portable version of our miniaturized laser heterodyne radiometer (mini-LHR) that simultaneously measures methane (CH4) and carbon dioxide (CO2) in the atmospheric column. The mini-LHR fits on a backpack frame, operates autonomously, and requires no infrastructure because it is powered by batteries charged by a folding 30 W solar panel. Similar to our earlier instruments, the mini-LHR is a passive laser heterodyne radiometer that operates by collecting sunlight that has undergone absorption by CH4 and CO2. Within the mini-LHR, sunlight is mixed with light from a distributive feedback (DFB) laser centered at approximately 1.64 μm where both gases have absorption features. The laser scans across these absorption features roughly every minute and the resulting beat signal is collected in the radio frequency (RF). Scans are averaged into half hour and hour data products and analyzed using the Planetary Spectrum Generator (PSG) retrieval to extract column mole fractions. Instrument performance is demonstrated through two deployments at significantly different sites in interior Alaska and Hawaii. The resolving power (λ/∆λ) is greater than 500,000 at 1.64 μm with precisions of better than 20 ppb and 1 ppm for CH4 and CO2, respectively. Because mini-LHR instruments are portable and can be co-located, they can be used to characterize bias between larger, stationary, column observing instruments. In addition, mini-LHRs can be deployed quickly to respond to transient events such as methane leaks or can be used for field studies targeting geographical regions.

Outcomes Assessment in Clinical Trials of Alzheimer's Disease and its Precursors: Readying for Short-term and Long-term Clinical Trial Needs

An evolving paradigm shift in the diagnostic conceptualization of Alzheimer's disease is reflected in its recently updated diagnostic criteria from the National Institute on Aging-Alzheimer's Association and the International Working Group. Additionally, it is reflected in the increased focus in this field on conducting prevention trials in addition to improving cognition and function in people with dementia. These developments are making key contributions towards defining new regulatory thinking around Alzheimer's disease treatment earlier in the disease continuum. As a result, the field as a whole is now concentrated on exploring the next-generation of cognitive and functional outcome measures that will support clinical trials focused on treating the slow slide into cognitive and functional impairment. With this backdrop, the International Society for CNS Clinical Trials and Methodology convened semi-annual working group meetings which began in spring of 2012 to address methodological issues in this area. This report presents the most critical issues around primary outcome assessments in Alzheimer's disease clinical trials, and summarizes the presentations, discussions, and recommendations of those meetings, within the context of the evolving landscape of Alzheimer's disease clinical trials.

A prospective cohort study assessing clinical referral management & workforce allocation within a UK regional medical genetics service

Ensuring patient access to genomic information in the face of increasing demand requires clinicians to develop innovative ways of working. This paper presents the first empirical prospective observational cohort study of UK multi-disciplinary genetic service delivery. It describes and explores collaborative working practices including the utilisation and role of clinical geneticists and non-medical genetic counsellors. Six hundred and fifty new patients referred to a regional genetics service were tracked through 850 clinical contacts until discharge. Referral decisions regarding allocation of lead health professional assigned to the case were monitored, including the use of initial clinical contact guidelines. Significant differences were found in the cases led by genetic counsellors and those led by clinical geneticists. Around a sixth, 16.8% (109/650) of referrals were dealt with by a letter back to the referrer or re-directed to another service provider and 14.8% (80/541) of the remaining patients chose not to schedule an appointment. Of the remaining 461 patients, genetic counsellors were allocated as lead health professional for 46.2% (213/461). A further 61 patients did not attend. Of those who did, 86.3% (345/400) were discharged after one or two appointments. Genetic counsellors contributed to 95% (784/825) of total patient contacts. They provided 93.7% (395/432) of initial contacts and 26.8% (106/395) of patients were discharged at that point. The information from this study informed a planned service re-design. More research is needed to assess the effectiveness and efficiency of different models of collaborative multi-disciplinary working within genetics services.

Performance on a pattern separation task by Alzheimer's patients shows possible links between disrupted dentate gyrus activity and apolipoprotein E ∈4 status and cerebrospinal fluid amyloid-β42 levels

INTRODUCTION

Emerging evidence suggests that decreased adult hippocampal neurogenesis represents an early critical event in the course of Alzheimer's disease (AD). In mice, adult neurogenesis is reduced by knock-in alleles for human apolipoprotein E (ApoE) ∈4. Decreased dentate gyrus (DG) neural progenitor cells proliferation has been observed in the triple-transgenic mouse model of AD (3xTg-AD); this reduction being directly associated with the presence of amyloid-β (Aβ) plaques and an increase in the number of Aβ-containing neurons in the hippocampus. Cognitive tasks involving difficult pattern separations have been shown to reflect DG activity and thus potentially neurogenesis in both animals and man. This study involved the administration of a pattern separation paradigm to Alzheimer's patients to investigate relationships between task performance and both ApoE status and cerebrospinal fluid (CSF) Aβ42 levels.

METHODS

The CDR System pattern separation task involves the presentation of pictures that must later be discriminated from closely similar pictures. This paper presents pattern separation data from 66 mild to moderate AD patients, of which 50 were genotyped and 65 in whom CSF Aβ42 was measured.

RESULTS

ApoE ∈4 homozygotes were not compromised on the easy pattern separations compared with the other patients, but they were statistically significantly poorer at the difficult separations. In all patients CSF Aβ42 correlated significantly with the ability to make the difficult discriminations, but not easier discriminations. Pattern separation speed correlated negatively with CSF Aβ42, and thus the association was not due to increased impulsivity.

CONCLUSIONS

These are, to our knowledge, the first human pattern separation data to suggest a possible genetic link to poor hippocampal neurogenesis in AD, as well as a relationship to Aβ42. Therapies which target neurogenesis may thus be useful in preventing the early stages of AD, notably in ApoE ∈4 homocygotes.

Cognitive performance in relapsing remitting multiple sclerosis: a longitudinal study in daily practice using a brief computerized cognitive battery

Background

There is need for a cognitive test battery that can be easily used in clinical practice to detect or monitor cognitive performance in patients with multiple sclerosis (MS). In order to conduct, in this patient group, a preliminary investigation of the validity and utility of a brief computerized battery, the Cognitive Drug Research (CDR) battery, we longitudinally assessed cognition in patients with relapsing remitting (RR) MS.

Methods

Forty-three mildly disabled, clinically active RRMS patients were repeatedly assessed with the Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) and five composite scores derived from the CDR computerized cognitive test system (CDR System): Power of Attention, Continuity of Attention, Quality of Working Memory, Quality of Episodic Memory and Speed of Memory. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) measured disability.

Results

The composite scores from the CDR battery generally showed excellent test-retest reliability over the repeated assessments, though was low on occasions for the Quality of Working Memory and Quality of Episodic Memory measures. The CDR measures tended to be highly correlated with other measures of cognition (DSST and PASAT) and were also strongly related to disability (EDSS and MSFC). Baseline scores indicated large impairments to visual information processing speed and attention (DSST, Cohen's d 1.1; Power of Attention d 1.4 [reaction time on tasks of focussed and sustained attention]), and a moderate impairment both to sustained attention (Continuity of Attention d 0.6) and complex information processing speed (Speed of memory d 0.7 [reaction time on tasks of working and episodic Memory]), when compared to normative data derived from healthy volunteers enrolled in a series of separate, prior clinical trials. Working memory (Quality of Working Memory) and episodic memory (Quality of Episodic Memory) were unimpaired.

Conclusions

Preliminary validation of the CDR System indicated that for most, but not all measures psychometric properties were adequate and the measures were related to disability (EDSS and MSFC) and other measures of cognition.

Computerized cognition assessment during acetylcholinesterase inhibitor treatment in Alzheimer's disease

OBJECTIVES

Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog) has become a standard clinical trials outcome for cognition, but has been recognized as deficient in areas including coverage of cognitive domains, sensitivity and standardization. Computerized test batteries may address some of these issues. The cognitive drug research computerized assessment (CDR) system is validated in Alzheimer's disease (AD). This study was designed to further evaluate validity in relation to ADAS-Cog, mini mental state examination (MMSE) and cerebrospinal fluid (CSF) biomarkers and psychometric properties, in a population of Alzheimer's patients on stable anticholinesterase treatment.

MATERIALS AND METHODS

Patients completed cognition assessments, CSF and blood sampling at baseline and 6 months later. Data for 65 patients were evaluated.

RESULTS

The CDR system demonstrated good psychometric properties in this population. Measures of psychomotor speed showed possible sensitivity to decline over 6 months.

CONCLUSIONS

There are a number of methodological problems with current cognition assessment methodology for clinical trials. Computerized measures and in particular millisecond reaction time measures, may address many of these issues.

Exploratory pilot study assessing the risk of cognitive impairment or sedation in the elderly following single doses of solifenacin 10 mg

OBJECTIVES

To assess the cognitive effects of single doses of solifenacin 10 mg compared with placebo (primary objective) and oxybutynin immediate release (IR) 10 mg (secondary objective) in elderly subjects.

METHODS

Single-centre, randomised, double-blind, placebo-controlled study in 12 healthy elderly volunteers, with three crossover periods separated by two 14-day washout periods. Each sequence consisted of a single dose of solifenacin 10 mg in one period, oxybutynin IR 10 mg in another and placebo in another. Aspects of attention, information processing, working memory, episodic memory and self-rated mood and alertness were tested using the validated Cognitive Drug Research computerised assessment system.

RESULTS

There was no evidence from absolute mean values or changes from baseline to suggest that solifenacin 10 mg impaired cognition or self-ratings of mood and alertness versus placebo. Post-hoc ANCOVA showed no statistically significant cognitive deterioration with solifenacin versus placebo, when measured at a time point closest to the probable C(max) of solifenacin. Oxybutynin was associated with statistically significant impairments in several measures of cognitive function at a time point corresponding with its probable C(max).

CONCLUSION

In this pilot study, single 10 mg doses of solifenacin did not show any clear propensity to impair cognitive function in a healthy elderly population.

Cognitive Performance by Humans During a Smoked Cocaine Binge-Abstinence Cycle

Five cocaine-dependent individuals completed a 22-day inpatient study of sleep and cognition. Following 3 days of drug-free baseline, participants underwent 3 days of twice-daily smoked cocaine base self-administration (6 50-mg doses, 14 minutes apart), followed by 15 days of abstinence. Each morning and afternoon, the CDR repeatable, multiple-version, computerized cognitive battery (whose stability following practice has been documented) was administered. During abstinence, performance deteriorated on vigilance tasks (especially reaction time) as well as on immediate and delayed verbal recognition tasks but not on working memory tasks. Declines were most evident in the afternoon. Data suggest that abstinence can unmask cognitive deficits induced by chronic cocaine use and circadian factors may mediate their severity.

The cognitive and psychomotor effects of remacemide and carbamazepine in newly diagnosed epilepsy

An international trial comparing remacemide hydrochloride with carbamazepine was undertaken in individuals with newly diagnosed epilepsy using a novel double-blind, parallel-group, double triangular sequential design. Patients with two or more partial or generalized tonic-clonic seizures in the previous year were randomized to remacemide or carbamazepine and titrated to a target dose of 600 mg/day. Subsequent dosage adjustments were allowed while maintaining the blind. Repeated assessments of neuropsychological function and mood were carried out using computerized and conventional measures. The trial was completed 20 months after initiation, following the second interim analysis. Efficacy as measured by seizure recurrence showed remacemide to be inferior to carbamazepine. Baseline cognitive and neuropsychological measures showed impairment across the whole patient population. Cognitive/neuropsychological performance at 8, 24, and 48 weeks was compared with that at baseline. Significant deterioration was seen on measures of information processing speed and attention after treatment with carbamazepine. The study data provide evidence for the utility and sensitivity of a number of cognitive assessments, which may be employed in future trials of antiepileptic drugs.

Benefits of rivastigmine on attention in dementia associated with Parkinson disease

In a 24-week, randomized, double-blind, placebo-controlled, multicenter study of rivastigmine, 487 patients with dementia associated with Parkinson disease underwent assessment of attention on the Cognitive Drug Research computerized cognitive assessment system before dosing and 16 and 24 weeks later. Significant benefits of rivastigmine over placebo were seen on all aspects of attention assessed: sustained attention, focused attention, consistence of responding, and central processing speed.

The role of angiogenesis in a murine tibial model of distraction osteogenesis

Distraction osteogenesis (DO) is one of the most dramatic in vivo applications of mechanical stimulation as a means of inducing bone regeneration. A simple and reproducible murine model of tibia distraction osteogenesis was developed using a monolateral fixator. Bone formation was assessed histologically over a 35-day time course. The steady state expression of a broad family of angiogenesis-associated genes was assessed by microarray hybridization analyses over the same time course, while the immediate gene response that was induced during each cycle of distraction was assessed at 30 min and 8 h after the first and last rounds of activation of the fixator. Distraction osteogenesis promoted new bone formation primarily through an intramembranous process with maximal osteogenesis during the active distraction period. Histological analysis also showed that dense cortical bone continued to be formed, during the consolidation phase, for 2 weeks after distraction ended. The analysis of steady state mRNA expression levels over the time course of DO showed that VEGF-A and neuropilin, an alternate receptor for VEGF-A, both angiopoietin (Ang) 1 and 2 factors, and the Ang receptor Tie2 were the critical angiogenic factors during DO. A key transcriptional regulator of many of the angiogenic factors, hypoxia-induced factor1alpha (Hif-1a), the FGF binding protein pleiotropin/OSF1, and multiple MMP(s), were also induced during the active distraction period. Examination of the expression of angiogenic factors that were induced after each cycle of activation, demonstrated that Hif-1a, Nrp1, and VEGF-A were all cyclically induced after each increment of distraction. These results suggest that these factors are early mediators that are produced by distraction and contribute toward the processes that promote bone formation. These experiments represent the first step in defining the molecular mechanisms that regulate skeletal regeneration and the functional relationship between angiogenesis and osteogenesis during distraction osteogenesis.

Abnormal stimulus-response intensity functions in posttraumatic stress disorder: an electrophysiological investigation

OBJECTIVE

The purpose of this study was to explore the relationship between combat-related posttraumatic stress disorder (PTSD) and specific augmentation versus reduction patterns for the N100 and P200 components of auditory event-related potentials evoked by tones of increasing intensity.

METHOD

Event-related potentials of subjects with PTSD (N=36), subjects with no psychopathology (N=20), subjects with major depression but no PTSD (N=10), and subjects with a history of chronic alcohol abuse but no PTSD (N=8) were recorded. Brain responses were evoked by a 2000-Hz tone presented in intensity blocks of 65, 72.5, 80, 87.5, and 95 dB (SPL).

RESULTS

Evoked data from five PTSD subjects were of poor quality and excluded from further analyses. For all but one subject with no psychopathology and for all subjects with a history of alcohol abuse or major depression (but no PTSD), the Cz amplitude of the P200 response component showed augmentation as a nearly linear function of tone intensity. As a group, subjects with PTSD showed no such increase in P200 response magnitude. Examination of the data from individual subjects with PTSD showed that 42% exhibited augmentation patterns similar to those seen for subjects in the comparison groups. However, 58% showed evidence of P200 reduction, with the response to the loudest tone being smaller than responses to tones of intermediate intensity.

CONCLUSIONS

The data suggest that there is a significant subgroup of patients with combat-related PTSD who enter into a state of protective inhibition at relatively low stimulus intensities. It is hypothesized that this is an appropriate adaptive mechanism for these subjects rather than an indication of a core neurobiological abnormality.

BDNF dependence in neuroblastoma

Neuroblastomas are heterogeneous tumors arising from sympathetic precursors in the neural crest. Growth factor stimulation of neuroblastomas promote diverse biological responses (mitogenesis, differentiation, cell death) depending on the particular tumor studied. Here we show that brief treatment with retinoic acid (RA) rendered the human neuroblastoma lines SY5Y, NGP, SMS-KCNR, and SK-N-SH dependent on brain-derived neurotrophic factor (BDNF) for survival. The BDNF- and trkB-expressing line SMS-KCN was dependent on an autocrine BDNF/trkB survival without exposure to RA. We conclude that the BDNF/trkB pathway plays an important role in neuroblastoma survival and speculate on a possible role in tumor pathogenesis.

Interferon treatment is not associated with a worsening of psychiatric symptoms in patients with hepatitis C

AIM

To study prospectively the psychiatric side effects of interferon-alpha in patients with hepatitis C.

METHODS

Sixty-three consecutive patients at a hepatitis clinic were recruited. All were assessed using a psychiatric interview (SCID) and monitored using a self-reporting psychiatric symptom questionnaire (SCL-90).

RESULTS

Patients on interferon did not suffer a drop in mood or an increase in anxiety or irritability. The subgroup with past depression also did not suffer an increase in depressive symptoms. No patients attempted suicide.

CONCLUSIONS

The risk of serious psychiatric symptoms when being treated with interferon-alpha may not be high. Psychiatric illness or the possibility of psychiatric complications should not be used as a reason to refuse this treatment to patients with hepatitis C.

The evolutionary genetic underpinnings of schizophrenia: the developmental instability model

The importance of genes in the etiology of schizophrenia is well known, but the manner in which the relevant genomic factors influence neural development and the nature of selection forces operating on these factors are poorly understood. In several prominent papers, Crow has provided a unique and comprehensive theory that attempts to deal with these issues. A central aspect of his theory is that a single gene leads to reduced cerebral lateralization, increased ventricular size, and risk for developing schizophrenia. He relies greatly on Annett's right shift theory of individual variation in handedness. An alternative approach, based on the construct of developmental instability, provides a different way to conceptualize genetic influences, selection forces, and atypical lateralization in schizophrenia. We suggest that the developmental instability model has stronger empirical support and is better grounded in contemporary evolutionary genetics.

Use of Extraneous Conversation in the Teaching of Nursing Skills

The purpose of this study was to explore the use of extraneous conversation as a distractor while assessing students' level of skill acquisition in the laboratory. The sample consisted of 50 nursing students enrolled in Introduction to Nursing Methods at a large Midwestern university. Subjects were assigned randomly to experimental and control groups. Extraneous conversation was used as a distractor during skill demonstration of intramuscular injections by the 25 students in the experimental group. The 25 students in the control group were not verbally distracted during skill demonstration. These skill demonstrations were videotaped. Data were collected from three evaluations: during the skill demonstration, a rating was based on the inclusion of critical elements; later on viewing the video tapes, faculty assigned a score to the performance based on the number of elements included; students were re-evaluated in the clinical setting based on guidance given by the instructor, performance of critical and noncritical elements, and the smoothness of the performance. Analysis of data from the ratings of students in the laboratory and from the ratings of students from the video tapes with the Wilcoxon rank-sum test revealed no significant differences (a = .05) in performance for the experimental and control groups. Chi-square analysis of data from the evaluation in the clinical setting indicated that students in the experimental group performed at a higher level than students in the control group.