Clinical utility of the standardized observation tool Autism Behavior Coding System for early intervention research in autism spectrum disorder

The Autism Behavior Coding System (ABCS) was developed to help evaluating the effectiveness of early intensive interventions in children with autism spectrum disorder (ASD). The video-based ABCS assesses eight core autistic behavioral variables during therapist-child interaction using standardized quantitative criteria, four behaviors according to their frequency of occurrence, four according to their duration. The present study focuses (1) on the correspondence of ABCS scores with scores on two standard clinical instruments (the ADOS-2 and an ASD-adaptation of the Children's Global Assessment Scale, DD-CGAS), (2) on the sensitivity to change of ABCS scores by the end of an intensive 18 days intervention period (EIP) and (c) on the predictability of short- and longer-term changes in social and repetitive behaviors from ABCS scores at baseline and EIP. Data from 51 children (42 M, 9 F; median age 45 months) followed over 1 year were available. There were significant correlations at baseline between several ABCS scores and ADOS-2 as well as DD-CGAS scores. Correlations at EIP between some ABCS and DD-CGAS scores were highly significant. Four ABCS scores reflected significant changes from baseline to EIP. Several baseline ABCS scores were predictive of DD-CGAS and ADOS-2 scores at EIP and Year 1. However, associations between ABCS score changes from baseline to EIP and the clinical scale changes by Year 1 were not significant. It is concluded that several ABCS scores have adequate clinical validity and sensitivity to change. The short-term changes in ABCS scores and their relationship to longer-term clinical changes need further study.

Femoral vein pulsatility: a simple tool for venous congestion assessment

BACKGROUND

Femoral vein Doppler (FVD) is simpler than the VExUS score which is a multimodal scoring system based on combination of IVC diameter, hepatic venous Doppler, portal vein pulsatility and renal vein Doppler, may be useful in assessing right ventricular overload and signs of venous congestion. There is limited data on the relationship between FVD and VExUS score.

RESULTS

Adult post-cardiac surgery patients were assessed for venous congestion using the VExUS score and FVD. Agreement between VExUS and FVD was studied using Kappa test, sensitivity, specificity, PPV and NPV for VExUS and FVD was calculated keeping CVP as gold standard. In total, 107 patients were enrolled, with a mean age of 55.67 ± 12.76. The accuracy of VExUS and FVD for detecting venous congestion was 80.37 (95% CI of 71.5 to 87.4) and 74.7 (95% CI of 65.4 to 82.6), respectively. The level of agreement between FVD and VExUS was moderate (Kappa value of 0.62, P < 0.001) while the agreement between FVD and CVP was weak (Kappa value of 0.49, P < 0.001).

CONCLUSION

FVD has good accuracy for detecting venous congestion and shows moderate agreement with VExUS grading. With potentially easier physical accessibility and a shorter learning curve for novices, it may be a simple and valuable tool for assessing venous congestion.

Using historical data to facilitate clinical prevention trials in Alzheimer disease? An analysis of longitudinal MCI (mild cognitive impairment) data sets

BACKGROUND

The Placebo Group Simulation Approach (PGSA) aims at partially replacing randomized placebo-controlled trials (RPCTs), making use of data from historical control groups in order to decrease the needed number of study participants exposed to lengthy placebo treatment. PGSA algorithms to create virtual control groups were originally derived from mild cognitive impairment (MCI) data of the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. To produce more generalizable algorithms, we aimed to compile five different MCI databases in a heuristic manner to create a "standard control algorithm" for use in future clinical trials.

METHODS

We compared data from two North American cohort studies (n=395 and 4328, respectively), one company-sponsored international clinical drug trial (n=831) and two convenience patient samples, one from Germany (n=726), and one from Switzerland (n=1558).

RESULTS

Despite differences between the five MCI samples regarding inclusion and exclusion criteria, their baseline demographic and cognitive performance data varied less than expected. However, the five samples differed markedly with regard to their subsequent cognitive performance and clinical development: (1) MCI patients from the drug trial did not deteriorate on verbal fluency over 3 years, whereas patients in the other samples did; (2) relatively few patients from the drug trial progressed from MCI to dementia (about 10% after 4 years), in contrast to the other four samples with progression rates over 30%.

CONCLUSION

Conventional MCI criteria were insufficient to allow for the creation of well-defined and internationally comparable samples of MCI patients. More recently published criteria for MCI or "MCI due to AD" are unlikely to remedy this situation. The Alzheimer scientific community needs to agree on a standard set of neuropsychological tests including appropriate selection criteria to make MCI a scientifically more useful concept. Patient data from different sources would then be comparable, and the scientific merits of algorithm-based study designs such as the PGSA could be properly assessed.

Designing dementia treatment studies: Diagnosis, efficacy criteria, and duration

Development of treatments for dementia is beset by special problems in defining the diagnosis, establishing efficacy criteria, and specifying the necessary duration of study. There is need for agreement among clinicians and scientists on diagnostic subgroups of dementia. Similarly, there is a need for harmonization of the regulatory guidelines in Europe, Japan, and the United States regarding the decision set of variables on which to base efficacy claims. The duration of trials must be based upon the intended claim: transient symptomatic benefit, maintained symptomatic benefit, or a therapeutic effect on disease progression. Claims other than transient benefit require long-term trials, suggested to be of at least six months in duration. Problems with long-term studies include slow patient accrual, high dropout rates, changing milieu, low return on investment, and lack of unanimity regarding regulatory requirements. Regulatory authorities must come to some accord, consonant with current clinical/scientific wisdom and consensus, regarding diagnosis, efficacy criteria, and feasible study duration, in order to attract continued sponsor investment in the development of antidementia treatments.

Short-Term and Highly Intensive Early Intervention FIAS: Two-Year Outcome Results and Factors of Influence

BACKGROUND

Comprehensive behaviorally or developmentally based early intervention programs have been shown to be effective in improving cognitive, social communicative, and adaptive skills of children with autism spectrum disorder (ASD). Besides the definition of relevant outcome predictors, the question of whether early intensive intervention positively changes core autism symptoms in children, as well as their long-term outcome, is an important issue for current research. The primary objective of the current study was to examine whether symptomatic and behavioral changes in children up to 4.5 years with ASD were sustained one and two years after an initial 18 days of intensive FIAS (Frühintervention bei autistischen Störungen) intervention.

METHODS

We analyzed the data of 32 young children with moderately severe to severe ASD who had been treated at the FIAS center between January 2011 and July 2017 and who had completed their 2-year follow-up in summer 2019.

RESULTS

ADOS total scores decreased significantly from baseline to the 1-year follow-up and from baseline to the 2-year follow-up (p < 0.01), with the most prominent change being from baseline to 2-year follow-up. The DD-C-GAS, a global scale used to assess four areas of everyday functioning, showed highly significant improvements on all subdomains. We found mostly significant correlations between results on both rating instruments at all time points, yet mostly no meaningful correlation between their changes over time. There was a close and statistically significant relationship between parents' treatment adherence and ADOS scores, indicating that the better parents' treatment adherence, the lower the children scored on the ADOS at 1- and 2-year follow-up. Overall, improvement on both scales was virtually independent of age and autism symptom severity at baseline, suggesting that older (>43 months) and more severely affected children (ADOS total score >20) may benefit from the FIAS intervention to the same extent as younger children do.

CONCLUSIONS

The results of the study indicate that the FIAS approach of providing an initial highly intensive 18-day intervention period, followed by 2 years of less intensive follow-up care had an impact on the core autism symptoms as well as the adaptive functioning of children with ASD.

Process research in early intensive intervention in autism spectrum disorder: Sensitivity to change of the autism behavior coding system

The development of sensitive measures to capture changes in core autism symptoms is crucial in early intervention research. The study examines the sensitivity to change of the Autism Behavior Coding System (ABCS), a video‐based instrument to assess core autism symptoms during therapist‐child interaction. Video sequences of 40 young children treated in the Frühintervention bei Autistischen Störungen center were analyzed with regard to the question of whether short‐term changes during an 18 day period of early intervention could be captured, and whether these results are reflected in an independent clinical assessment (Developmental Disorders‐Child‐Global Assessment Scale [DD‐C‐GAS]). ABCS results showed statistically significant improvements on behavioral domains such as “expression of wishes” and “social cooperative behavior” (P < 0.01), less pronounced on “eye contact.” Improvements on the DD‐C‐GAS were highly significant on all subdomains. Both scales showed high correlations within their subdomains, yet no significant correlations between the changes in both instruments' scores were found. An additional analysis between the DD‐C‐GAS scores at day 18 and the changes in the ABCS scores showed statistically significant associations in the expected direction between the changes in the variable “eye contact” and all DD‐C‐GAS subdomains. The correspondence of the two levels of assessment is low, but the specifics of this relationship deserve further study. The ABCS may prove useful in addition to standard assessment tools, especially in early intervention research settings, as it allows reliable analysis of core behavioral elements in young children with autism. Autism Res 2019, 12: 1817–1828. © 2019 The Authors. Autism Research published by International Society for Autism Research published by Wiley Periodicals, Inc.

Lay Summary

The study examined the sensitivity of an autism‐specific video coding system (ABCS) in assessing changes after an 18 day period of intensive early intervention. Video sequences of therapist‐child‐interaction of 40 young children with autism spectrum disorder (ASD) were analyzed. Children's behavior improved in expression of wishes, social cooperativity and eye contact. A therapist‐based global assessment scale also showed important improvement after 18 days, yet both assessment instruments showed weak correlations between their respective changes. We showed that the ABCS may prove useful in capturing short‐term changes in autism‐related behaviors, especially in early intervention research.

Age-Dependent Phenotypic Expression of a Pattern Dystrophy of the Retina

We studied a family with pattern dystrophy of the retina (PDR) in order to elucidate the clinical course of the disorder, relations between the different forms, and the mode of inheritance. Thirty-nine family members, representing three generations, underwent a thorough ophthalmological examination, with fluorescein angiography whenever a macular abnormality was suspected. Of family members over the age of 32 years, 46.7% showed signs of PDR. We classified the clinical forms of PDR in this family into four types: minimal lesion, pseudovitelliform type, butterfly-spider type, and late-stage lesion. These forms were predominant in the order cited in age groups 31-40 years, 41-50, 51-60, and > 60 years. Significant visual loss occurred only after the age of 50 years, when 8 of 14 eyes had visual acuity of less than 20/25. Inheritance was autosomal dominant. PDR presented different clinical forms in members of this family, and in successive age classes patterns of increasing severity prevailed. Thus, the different phenotypic forms apparently represent transient stages related to the age of the patient.

Assessing symptoms during comprehensive interventions for young children with autism spectrum disorder: Development and preliminary analysis of the Autism Behaviour Coding System (ABCS)

The aims of this paper are to present the Autism Behaviour Coding System (ABCS), a novel, video-based observational instrument for assessing core autism symptoms during intensive early interventions in autism spectrum disorder (ASD), to provide preliminary data on its psychometric characteristics and to discuss its clinical utility. Video recordings of child-therapist interactions during the 'Frühintervention bei autistischen Störungen' (FIAS) were coded by treatment-independent raters who were blind with respect to the temporal order of the sequences. We assessed inter-rater reliability using intra-class correlations (ICCs). Mean ICCs ranged from 0.85 to 0.90. We analysed the sensitivity of the ABCS to change by comparing the change in ABCS scores with the change in a validated external measure of level of functioning (Developmental Disorder-Child-Global Assessment of functioning Scale, DD-C-GAS) in a sample of 15 children who received intensive treatment. Both the ABCS and DD-C-GAS indicated that the intervention improved symptoms. The ABCS has promise as a research instrument and has good to excellent inter-rater agreement and sensitivity to intervention-related changes. This pilot study suggests that the ABCS may be useful as an objective method of assessing the proximal effects of therapy in young children with ASD.

Mild cognitive impairment and deficits in instrumental activities of daily living: a systematic review

INTRODUCTION

There is a growing body of evidence that subtle deficits in instrumental activities of daily living (IADL) may be present in mild cognitive impairment (MCI). However, it is not clear if there are IADL domains that are consistently affected across patients with MCI. In this systematic review, therefore, we aimed to summarize research results regarding the performance of MCI patients in specific IADL (sub)domains compared with persons who are cognitively normal and/or patients with dementia.

METHODS

The databases PsycINFO, PubMed and Web of Science were searched for relevant literature in December 2013. Publications from 1999 onward were considered for inclusion. Altogether, 497 articles were retrieved. Reference lists of selected articles were searched for potentially relevant articles. After screening the abstracts of these 497 articles, 37 articles were included in this review.

RESULTS

In 35 studies, IADL deficits (such as problems with medication intake, telephone use, keeping appointments, finding things at home and using everyday technology) were documented in patients with MCI. Financial capacity in patients with MCI was affected in the majority of studies. Effect sizes for group differences between patients with MCI and healthy controls were predominantly moderate to large. Performance-based instruments showed slight advantages (in terms of effect sizes) in detecting group differences in IADL functioning between patients with MCI, patients with Alzheimer's disease and healthy controls.

CONCLUSION

IADL requiring higher neuropsychological functioning seem to be most severely affected in patients with MCI. A reliable identification of such deficits is necessary, as patients with MCI with IADL deficits seem to have a higher risk of converting to dementia than patients with MCI without IADL deficits. The use of assessment tools specifically designed and validated for patients with MCI is therefore strongly recommended. Furthermore, the development of performance-based assessment instruments should be intensified, as they allow a valid and reliable assessment of subtle IADL deficits in MCI, even if a proxy is not available. Another important point to consider when designing new scales is the inclusion of technology-associated IADL. Novel instruments for clinical practice should be time-efficient and easy to administer.

Become Related: FIAS, an Intensive Early Intervention for Young Children with Autism Spectrum Disorders

BACKGROUND

In autism spectrum disorders (ASDs), impairments in fundamental social abilities and a lack of interest in social stimuli become apparent early in life. These impairments are thought to negatively affect further brain and behavioural development. Early intensive interventions can help to attenuate social-development and other risk factors and, thus, to ameliorate the deficits associated with ASDs. We present FIAS, an intensive early intervention approach for young children with ASD, which aims at developing children's social motivation. During 18 days, therapists work continuously for 6 h a day with the affected child, involving the whole family in a day care setting. Follow-up care at home over 1 year as well as fresh-up interventions and inclusion in kindergarten or a play group should stabilise the effects and help to respond to further challenges.

MATERIAL AND METHODS

Here, we present observations from the first 12 patients (25-48 months of age) treated according to the FIAS approach. We evaluated changes in core autistic symptoms and level of functioning after the 18 days of intensive intervention. Beyond standardised assessment, two innovative video-based instruments (Autism Behaviour Coding System and Evaluationsfragebogen) have been developed to assess autistic symptoms and interaction parameters during intervention.

RESULTS

Improvements were noted in most core autistic symptom domains, with the highest effect sizes in domains like eye contact, communication, repetitive behaviour, imitation, motivation and reciprocity. In addition, the level of functioning significantly improved.

CONCLUSIONS

The first evaluation of the FIAS approach shows promising results, as the FIAS intervention appears to improve core autistic symptom domains as well as the level of everyday functioning. Limitations of this study are the small sample size and the lack of a control group. A more comprehensive and longitudinal evaluation is in progress; this will focus on the stability of the observed effects and will attempt to identify potential predictors of treatment response. © 2015 S. Karger AG, Basel.

The effect of zoledronic acid on the fracture risk in men with osteoporosis

BACKGROUND

Prospective, placebo-controlled, double-blind, randomized studies on osteoporosis treatment with bisphosphonates in men are rare. This review focuses on a recent trial and compares the results with other studies.

METHODS

This review provides a summary of recent literature on fracture risk in men following treatment with zoledronic acid. According to a recent clinical study with 1,199 men, zoledronic acid was linked to a lower risk of vertebral fractures. In this manuscript, a re-analysis of the presented statistical data will be demonstrated by performing a Bonferroni-correction to adjust for type 1 error accumulation in multiple statistical tests.

RESULTS

It will be shown that the provided evidence linking zoledronic acid to a lower fracture risk in male osteoporosis is true, but less pronounced than originally assumed.

CONCLUSION

Comparative clinical studies are recommended, where the benefits of different bisphosphonates are compared to each other under the same experimental conditions.

A Novel Study Paradigm for Long-term Prevention Trials in Alzheimer Disease: The Placebo Group Simulation Approach (PGSA): Application to MCI data from the NACC database

INTRODUCTION

The PGSA (Placebo Group Simulation Approach) aims at avoiding problems of sample representativeness and ethical issues typical of placebo-controlled secondary prevention trials with MCI patients. The PGSA uses mathematical modeling to forecast the distribution of quantified outcomes of MCI patient groups based on their own baseline data established at the outset of clinical trials. These forecasted distributions are then compared with the distribution of actual outcomes observed on candidate treatments, thus substituting for a concomitant placebo group. Here we investigate whether a PGSA algorithm that was developed from the MCI population of ADNI 1*, can reliably simulate the distribution of composite neuropsychological outcomes from a larger, independently selected MCI subject sample.

METHODS

Data available from the National Alzheimer's Coordinating Center (NACC) were used. We included 1523 patients with single or multiple domain amnestic mild cognitive impairment (aMCI) and at least two follow-ups after baseline. In order to strengthen the analysis and to verify whether there was a drift over time in the neuropsychological outcomes, the NACC subject sample was split into 3 subsamples of similar size. The previously described PGSA algorithm for the trajectory of a composite neuropsychological test battery (NTB) score was adapted to the test battery used in NACC. Nine demographic, clinical, biological and neuropsychological candidate predictors were included in a mixed model; this model and its error terms were used to simulate trajectories of the adapted NTB.

RESULTS

The distributions of empirically observed and simulated data after 1, 2 and 3 years were very similar, with some over-estimation of decline in all 3 subgroups. The by far most important predictor of the NTB trajectories is the baseline NTB score. Other significant predictors are the MMSE baseline score and the interactions of time with ApoE4 and FAQ (functional abilities). These are essentially the same predictors as determined for the original NTB score.

CONCLUSION

An algorithm comprising a small number of baseline variables, notably cognitive performance at baseline, forecasts the group trajectory of cognitive decline in subsequent years with high accuracy. The current analysis of 3 independent subgroups of aMCI patients from the NACC database supports the validity of the PGSA longitudinal algorithm for a NTB. Use of the PGSA in long-term secondary AD prevention trials deserves consideration.

Encysted peritoneal hydatidosis in a child — the effectiveness of pre-operative therapy with a combination of praziquantel and albendazole

A child with encysted peritoneal hydatidosis was found to be completely cured after 3 months of combined therapy with praziquantel and albendazole followed by resection of a huge peritoneal cyst and the removal of numerous, dead, daughter cysts.

Modeling the course of Alzheimer's disease to improve clinical trials: symposium report

In a symposium held at the Clinical Trials in Alzheimer's Disease conference in Monte Carlo, Monaco (29 to 31 October 2012) three different, not mutually exclusive approaches to improve and facilitate clinical trials with anti-dementia drugs were presented and discussed. All three approaches are summarized in this manuscript. Core suggestions are: stratification of trial participants at the outset of studies, using cognitive and disease-course characteristics available at baseline; creating new composite cognitive scores for optimizing responsiveness to decline in early and very early Alzheimer's disease; and replacing some of the conventional long-term placebo-controlled trials in advanced stages of drug development, using the placebo group simulation approach. Future efforts should focus on incorporating, where appropriate, the suggestions provided at the symposium into clinical trials now being planned.

Progress and problems in muscle glycogenoses

In this selective review, we consider a number of unsolved questions regarding the glycogen storage diseases (GSD). Thus, the pathogenesis of Pompe disease (GSD II) is not simply explained by excessive intralysosomal glycogen storage and may relate to a more general dysfunction of autophagy. It is not clear why debrancher deficiency (GSD III) causes fixed myopathy rather than exercise intolerance, unless this is due to the frequent accompanying neuropathy. The infantile neuromuscular presentation of branching enzyme deficiency (GSD IV) is underdiagnosed and is finally getting the attention it deserves. On the other hand, the late-onset variant of GSD IV (adult polyglucosan body disease APBD) is one of several polyglucosan disorders (including Lafora disease) due to different etiologies. We still do not understand the clinical heterogeneity of McArdle disease (GSD V) or the molecular basis of the rare fatal infantile form. Similarly, the multisystemic infantile presentation of phosphofructokinase deficiency (GSD VII) is a conundrum. We observed an interesting association between phosphoglycerate kinase deficiency (GSD IX) and juvenile Parkinsonism, which is probably causal rather than casual. Also unexplained is the frequent and apparently specific association of phosphoglycerate mutase deficiency (GSD X) and tubular aggregates. By paying more attention to problems than to progress, we aimed to look to the future rather than to the past.

A randomized trial of 4-aminopyridine in EA2 and related familial episodic ataxias

OBJECTIVE

The therapeutic effects of 4-aminopyridine (4AP) were investigated in a randomized, double-blind, crossover trial in 10 subjects with familial episodic ataxia with nystagmus.

METHODS

After randomization, placebo or 4AP (5 mg 3 times daily) was administered for 2 3-month-long treatment periods separated by a 1-month-long washout period. The primary outcome measure was the number of ataxia attacks per month; the secondary outcome measures were the attack duration and patient-reported quality of life (Vestibular Disorders Activities of Daily Living Scale [VDADL]). Nonparametric tests and a random-effects model were used for statistical analysis.

RESULTS

The diagnosis of episodic ataxia type 2 (EA2) was genetically confirmed in 7 subjects. Patients receiving placebo had a median monthly attack frequency of 6.50, whereas patients taking 4AP had a frequency of 1.65 (p = 0.03). Median monthly attack duration decreased from 13.65 hours with placebo to 4.45 hours with 4AP (p = 0.08). The VDADL score decreased from 6.00 to 1.50 (p = 0.02). 4AP was well-tolerated.

CONCLUSIONS

This controlled trial on EA2 and familial episodic ataxia with nystagmus demonstrated that 4AP decreases attack frequency and improves quality of life.

LEVEL OF EVIDENCE

This crossover study provides Class II evidence that 4AP decreases attack frequency and improves the patient-reported quality of life in patients with episodic ataxia and related familial ataxias.

For debate: substituting placebo controls in long-term Alzheimer's prevention trials

Introduction

Novel compounds with potential to attenuate or stop the progression of Alzheimer's disease (AD) from its presymptomatic stage to dementia are being tested in man. The study design commonly used is the long-term randomized, placebo-controlled trial (RPCT), meaning that many patients will receive placebo for 18 months or longer. It is ethically problematic to expose presymptomatic AD patients, who by definition are at risk of developing dementia, to prolonged placebo treatment. As an alternative to long-term RPCTs we propose a novel clinical study design, termed the placebo group simulation approach (PGSA), using mathematical models to forecast outcomes of presymptomatic AD patients from their own baseline data. Forecasted outcomes are compared with outcomes observed on candidate drugs, thus replacing a concomitant placebo group.

Methods

First models were constructed using mild cognitive impairment (MCI) data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. One outcome is the Alzheimer Disease Assessment Scale - cognitive subscale (ADAScog) score after 24 months, predicted in a linear regression model; the other is the trajectory over 36 months of a composite neuropsychological test score (Neuro-Psychological Battery (NP-Batt)), using a mixed model. Demographics and clinical, biological and neuropsychological baseline values were tested as potential predictors in both models.

Results

ADAScog scores after 24 months are predicted from gender, obesity, Functional Assessment Questionnaire (FAQ) and baseline scores of Mini-Mental State Examination, ADAScog and NP-Batt with an R² of 0.63 and a residual standard deviation of 0.67, allowing reasonably precise estimates of sample means. The model of the NP-Batt trajectory has random intercepts and slopes and fixed effects for body mass index, time, apolipoprotein E4, age, FAQ, baseline scores of ADAScog and NP-Batt, and four interaction terms. Estimates of the residual standard deviation range from 0.3 to 0.5 on a standard normal scale. If novel drug candidates are expected to diminish the negative slope of scores with time, a change of 0.04 per year could be detected in samples of 400 with a power of about 80%.

Conclusions

First PGSA models derived from ADNI MCI data allow prediction of cognitive endpoints and trajectories that correspond well with real observed values. Corroboration of these models with data from other observational studies is ongoing. It is suggested that the PGSA may complement RPCT designs in forthcoming long-term drug studies with presymptomatic AD individuals.

Head position during resting modifies spontaneous daytime decrease of downbeat nystagmus

BACKGROUND

The intensity of downbeat nystagmus (DBN) decreases during the daytime when the head is in upright position.

OBJECTIVE

This prospective study investigated whether resting in different head positions (upright, supine, prone) modulates the intensity of DBN after resting.

METHODS

Eye movements of 9 patients with DBN due to cerebellar (n = 2) or unknown etiology (n = 7) were recorded with video-oculography. Mean slow-phase velocities (SPV) of DBN were determined in the upright position before resting at 9 am and then after 2 hours (11 am) and after 4 hours (1 pm) of resting. Whole-body positions during resting were upright, supine, or prone. The effects of all 3 resting positions were assessed on 3 separate days in each patient.

RESULTS

Before resting (9 am), the average SPV ranged from 3.05 °/s to 3.6 °/s on the separate days of measurement. After resting in an upright position, the average SPV at 11 am and 1 pm was 0.65 °/sec, which was less (p < 0.05) than after resting in supine (2.1 °/sec) or prone (2.22 °/sec) positions.

CONCLUSION

DBN measured during the daytime in an upright position becomes minimal after the patient has rested upright. The spontaneous decrease of DBN is less pronounced when patients lie down to rest. This indicates a modulation by otolithic input. We recommend that patients with DBN rest in an upright position during the daytime.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for patients with DBN 2 hours of rest in the upright position decreases nystagmus more than 2 hours of rest in the supine or prone positions (relative improvement 79% upright, 33% supine, and 38% prone: p < 0.05).