Validation of a Behavioral Approach for Measuring Saccades in Parkinson's Disease

Speed and control of saccades are related to disease progression and cognitive functioning in Parkinson's disease (PD). Traditional eye-tracking complexities encumber application for individual evaluations and clinical trials. The authors examined psychometric properties of standalone tasks for reflexive prosaccade latency, volitional saccade initiation, and saccade inhibition (antisaccade) in a heterogeneous sample of 65 PD patients. Demographics had minimal impact on task performance. Thirty-day test–retest reliability estimates for behavioral tasks were acceptable and similar to traditional eye tracking. Behavioral tasks demonstrated concurrent validity with traditional eye-tracking measures; discriminant validity was less clear. Saccade initiation and inhibition discriminated PD patients with cognitive impairment. The present findings support further development and use of the behavioral tasks for assessing latency and control of saccades in PD.     

Cluster analysis reveals distinct patterns of saccade impairment and their relation to cognitive profiles in Parkinson's disease

Saccade performance has been reported to be altered in Parkinson's disease (PD), however, with a large variability between studies as both motor and cognitive impairment interfere with oculomotor control. The aim of this study was to identify different patterns in saccade alterations in PD using a data-driven approach and to explore their relationship with cognitive phenotypes. Sixty-one participants with PD and 25 controls performed eye-tracking (horizontal and vertical prosaccades, antisaccades) and neuropsychological testing. Hierarchical cluster analysis was applied to the eye-tracking data to subsequently compare the clusters based on demographical, clinical and cognitive characteristics. The three identified clusters of saccade alterations differed in cognitive profiles from healthy controls, but not in PD-related motor symptoms or demographics. The rate of directive errors in the antisaccade task was increased in clusters 1 and 2. Further, cluster 1 was defined by a general disinhibition of reflexive saccades and executive dysfunction in the neuropsychological evaluation. In cluster 2, prolonged saccade latencies and hypometria were accompanied by multidomain cognitive impairment. The cluster 3 showed increased antisaccade latency and vertical hypometria despite lack of evidence for cognitive impairment. Our results suggest that there may be at least two opposing patterns of saccade alterations associated with cognitive impairment in PD, which may explain some of the contradictory results of previous studies.     

自主控制眼跳：实验范式、神经机制和应用

自主控制眼跳是眼跳类型之一。自主控制眼跳实验范式为研究各种脑损伤,神经疾病和精神失调提供了一种新的研究手段,为研究眼跳的神经机制以及反应抑制、空间工作记忆等高级认知功能提供了重要的方法。文章介绍了自主控制眼跳的两种实验范式：反向眼跳和记忆导向眼跳,阐述了自主控制眼跳的神经机制及其实验范式的应用,指出自主控制眼跳实验范式为评定精神分裂症等脑功能失调病人的神经功能状态提供了重要的信息,为研究各种脑功能失调和精神疾病提供了重要的研究方法。今后的研究趋势是眼跳研究与神经成像技术和临床观察相结合     

Hemispheric Asymmetry and Regional Differences in Electroencephalographic Alpha Activity at the Wake-Sleep Transition

Electroencephalographic (EEG) alpha activity at the wake-sleep transition was studied in six right-handed adults in terms of hemispheric asymmetry and regional differences. Twelve-channel EEGs with linked mastoid references were recorded together with horizontal and vertical electro-oculograms (EOGs). Two types of alpha coefficient were obtained every 5.12 s by computing the relative proportion of right vs. left alpha band power and of anterior vs. posterior alpha band power. Four stages were scored using EEG sleep patterns (theta waves, vertex sharp waves, spindles, and K complex) and slow eye movement (SEM): stage W had neither EEG sleep patterns nor SEM; stage D1 had SEM and no EEG sleep patterns; stage D2 had theta waves or vertex sharp waves and SEM; stage S had spindles or K complex without SEM. It was found that the two types of alpha coefficient changed as a function of EEG-EOG stage and were correlated. Right-decreased and anterior-shifted alpha activities were manifest at stages D2 and S. Drowsiness was considered to be a heterogeneous state, exhibiting different spatial changes in alpha activity between stages D1 and D2.     

Targeted Paced and Unpaced Movements in the Transverse and Sagittal Planes

Five experiments are reported related to control of arm movement in the sagittal and transverse planes when making paced and unpaced movements. A single group of 12 participants and the same equipment were used in the main experiments to allow comparisons across conditions. As well as the 2 different directions of movement, there were movements that were time-constrained (as in the W. D. A. Beggs &; C. I. Howarth, 1971, 1972a,b paradigm) and movements that were constrained by the ending tolerance (as in Fitts' paradigm). Results showed that, for movement times as high as 900 ms, the Schmidt and Beggs and Howarth models appeared to describe the time for movements that had time constraint. Fitts' law (P. M. Fitts, 1954 Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47, 381–391.[Crossref], [PubMed] , [Google Scholar]; P. M. Fitts &; J. R. Peterson, 1964) applied to movements that were constrained by final accuracy. These results were independent of whether the target was in the aiming or stopping movement direction. A new interpretation of data for movements with time constraint is presented, based on the possible number of accuracy submovements available when near the target. This model suggests that the standard deviation of hits at the target is not dependent on the time spent in reaching the target region, but largely on the time remaining in order to produce final accuracy at the target.     

Single-Joint Movements in Parkinson's Disease: A Pulse-Width and Pulse-Height Theory Review

The process by which the brain controls single-joint movements (SJM) is still not well understood. Some studies have defined rules describing the duration and magnitude of the agonist and antagonist muscles. Therefore, the purpose of this study was to analyze scientific publications about the electromyographic characteristics of SJM performed by patients with Parkinson's disease. A bibliographical review of the years 1989–2015 was performed using keywords such as electromyography, upper limb, and Parkinson's disease. After applying the inclusion criteria, 8 articles were included for analysis. The literature indicates that despite the lack of studies, it is possible to assume that considering the SJM, those with Parkinson's disease only control the magnitude of electromyography activation, being consistent only with the pulse-height theory control.     

The Visual Spatial Learning Test: Differential impairment during the premanifest and manifest stages of Huntington's disease

Visual spatial memory was assessed using the Visual Spatial Learning Test (VSLT) in individuals with mild to moderate Huntington's disease (HD), pre‐manifest gene carriers for HD, and demographically similar controls. The VSLT has been demonstrated to be a valid, normed measure of non‐verbal memory involving minimal motoric responses. The VSLT assesses immediate and delayed memory for designs, positions of the designs, and design/position associations. The HD group was significantly impaired (p < .05) relative to both the control and Pre‐HD groups on immediate and delayed memory for the designs, positions, and design/position associations. Although there were no differences between the Pre‐HD and control groups on immediate or delayed memory for designs or positions, the Pre‐HD group was significantly impaired (p < .05) relative to the control group on immediate and delayed memory for design/position associations. The results offer novel insight into a relatively unexamined memory deficit that may occur in gene carriers for HD prior to phenoconversion. The data indicate that the VSLT may be a useful measure of visuospatial memory during the premanifest and manifest stages of HD.     

Effect of Age and Gender in the Control of Elbow Flexion Movements

In previous studies of rapid elbow movements in young healthy men, characteristic task-dependent changes in the patterns of muscle activation when movement speed or distance was varied have been reported. In the present study, the authors investigated whether age or gender is associated with changes in the patterns of muscle activity previously reported in young men. Arm movements of 10 healthy older and 10 healthy younger participants (5 men and 5 women in each group) were studied. Surface electromyograms (EMGs) from agonist (biceps) and antagonist (triceps) muscles, kinematic and kinetic parameters, as well as anthropometric and strength measures were recorded. All 4 groups of participants showed similar task- (distance or speed) dependent changes in biphasic EMG activity. Similar modulation of the initial rate of rise of the EMG, integrated agonist and antagonist EMG activity, as well as their relative timing were observed in all 4 groups. Those results suggest that older individuals of both genders retain the control strategies for elbow movements used by young individuals. Despite the qualitative similarities in the patterns of muscle activation, the men moved more quickly than the women, and younger participants moved more quickly than older participants. Those performance differences could not be explained in terms of differences in body size and strength alone.     

Destination and source memory in Huntington's disease

Destination memory refers to the recall of the destination of previously relayed information, and source memory refers to the recollection of the origin of received information. We compared both memory systems in Huntington's disease (HD) participants. For this, HD participants and healthy adults had to put 12 items in a black or a white box (destination task), and to extract another 12 items from a blue or a red box (source task). Afterwards, they had to decide in which box each item had previously been deposited (destination memory), and from which box each item had previously been extracted (source memory). HD participants showed poorer source as well as destination recall performance than healthy adults in the proposed tasks. Correlation analysis showed that destination recall was significantly correlated with episodic recall in HD participants. Destination memory impairment in HD participants seems to be considerably influenced by their episodic memory performance.     

Illness perceptions and coping explain well-being in patients with Huntington's disease

This study sought to investigate the contribution of illness perceptions and coping mechanisms to the explanation of well-being of patients with Huntington's disease (HD). We investigated the Leventhal et al. assumption of the Self-regulation Model that coping mediates the relationship between illness perceptions and patients’ well-being. Illness perceptions, coping, and well-being in 77 HD patients were assessed with validated questionnaires; motor performance and cognitive performance were assessed with Huntington's disease-specific measures. The assumption that illness perceptions influence HD patients’ well-being via coping was not supported. The results indicate that both coping and illness perceptions made a major contribution to the explanation of variance in HD patients’ psychosocial well-being. Variance in their physical well-being was explained by illness perceptions mainly. The need to conduct further research on the interrelationships between illness perceptions, coping, and well-being in this patient category is discussed.     

Encoding Strategies in Primary School Children: Insights From an Eye-Tracking Approach and the Role of Individual Differences in Attentional Control

The authors explored different aspects of encoding strategy use in primary school children by including (a) an encoding strategy task in which children's encoding strategy use was recorded through a remote eye-tracking device and, later, free recall and recognition for target items was assessed; and (b) tasks measuring resistance to interference (flanker task) and inhibition of attention to task-irrelevant stimuli (distractibility). Results revealed that the ability to inhibit distraction and resist interference undergoes developmental changes between the ages of 7–10 years. At the same time, children's capability to strategically focus on task-relevant aspects also continues to improve in primary school years. Although there were substantial relationships between encoding strategies and later recognition, encoding strategies appeared to be unrelated to basic aspects of attentional control.     

ANOVA and the variance homogeneity assumption: Exploring a better gatekeeper

Valid use of the traditional independent samples ANOVA procedure requires that the population variances are equal. Previous research has investigated whether variance homogeneity tests, such as Levene's test, are satisfactory as gatekeepers for identifying when to use or not to use the ANOVA procedure. This research focuses on a novel homogeneity of variance test that incorporates an equivalence testing approach. Instead of testing the null hypothesis that the variances are equal against an alternative hypothesis that the variances are not equal, the equivalence-based test evaluates the null hypothesis that the difference in the variances falls outside or on the border of a predetermined interval against an alternative hypothesis that the difference in the variances falls within the predetermined interval. Thus, with the equivalence-based procedure, the alternative hypothesis is aligned with the research hypothesis (variance equality). A simulation study demonstrated that the equivalence-based test of population variance homogeneity is a better gatekeeper for the ANOVA than traditional homogeneity of variance tests.     

Grip Control in Children before,during, and after Impulsive Loading

The manipulation of small objects requires continuous contributions from both predictive and reactive mechanisms. The authors aimed to study the development of predictive and reactive mechanisms used by children from 6 to 14 years of age to manage impulsive loading. The load of a handheld object was increased rapidly by the drop of a weight hung on the object. The drop was triggered either by the child (predictive condition) or by the examiner (reactive condition). Regardless of the condition, the control strategy was refined with age. Younger children were unable to adapt their grip force (GF) to the friction of their fingers, whereas the older children provided GF that was well adapted to their variable coefficient of friction, thereby producing a secure grip. This reflected either an inadequate amount of force or an inability to integrate cutaneous information from the fingers in younger children. Additionally, a modulation with age for both predictive and reactive mechanisms was observed. All together, the better predictive abilities and the more secure grip exhibited by older children allow decreased slipping and improved performance in an impulsive loading task.     

字、词的识别加工在中文阅读眼动控制中的作用:来自消失文本方面的证据*

实验采用消失文本范式,操纵注视点上字、词消失单元和呈现时间,探讨字词视觉呈现、字词识别加工对中文阅读眼动过程的影响。结果发现:(1)0 ms延迟时间的消失文本均严重影响总阅读时间,其中单字消失、单词消失与双字消失对阅读效率的影响没有差别;各消失条件都导致较多回视次数;相对于其他消失条件,单字消失和双字消失导致较多的再注视词数。(2)120 ms延迟时间的消失文本均不影响总阅读时间,但会通过取消部分眼跳的方式导致注视持续时间的增加,字消失单元(单字消失和双字消失)迫使读者取消部分词内再注视眼跳。综合两种延迟时间下各消失文本的数据可见,字识别和词汇识别相互影响,词在中文阅读的词内再注视眼跳选择目标环节起到重要作用。     

Action‐semantic and syntactic deficits in subjects at risk for Huntington's disease

Frontostriatal networks play critical roles in grounding action semantics and syntactic skills. Indeed, their atrophy distinctively disrupts both domains, as observed in patients with Huntington's disease (HD) and Parkinson's disease, even during early disease stages. However, frontostriatal degeneration in these conditions may begin up to 15 years before the onset of clinical symptoms, opening avenues for pre‐clinical detection via sensitive tasks. Such a mission is particularly critical in HD, given that patients’ children have 50% chances of inheriting the disease. Against this background, we assessed whether deficits in the above‐mentioned domains emerge in subjects at risk to develop HD. We administered tasks tapping action semantics, object semantics, and two forms of syntactic processing to 18 patients with HD, 19 asymptomatic first‐degree relatives, and sociodemographically matched controls for each group. The patients evinced significant deficits in all tasks, but only those in the two target domains were independent of overall cognitive state. More crucially, relative to controls, the asymptomatic relatives were selectively impaired in action semantics and in the more complex syntactic task, with both patterns emerging irrespective of the subjects’ overall cognitive state. Our findings highlight the relevance of these dysfunctions as potential prodromal biomarkers of HD. Moreover, they offer theoretical insights into the differential contributions of frontostriatal hubs to both domains while paving the way for innovations in diagnostic procedures.     

Everyday‐like memory for objects in ageing and Alzheimer's disease assessed in a visually complex environment: The role of executive functioning and episodic memory

To investigate everyday memory, more and more studies rely on virtual‐reality applications to bridge the gap between in situ approaches and laboratory settings. In this vein, the present study was designed to assess everyday‐like memory from the virtual reality‐based Human Object Memory for Everyday Scenes (HOMES) test (Sauzéon et al., 2012 , Exp. Psychol., 59, 99) in ageing and in Alzheimer's disease (AD). Two aims motivated this study: the first was to assess multiple processes of episodic memory (EM) functioning embedded within contexts closely related to real life in ageing and AD using the multi‐trial free‐recall paradigm, and the second aim was to evaluate the mediating effects of executive functioning (EF), EM, and subjective memory complaints (SMCs) on age differences in the HOMES measures and in AD. To this end, the HOMES test and neurocognitive tests of EF and EM were administered to 23 younger adults, 23 older adults, and 16 patients with AD. The results were: firstly, compared to young adults, elderly adults presented only free‐recall decline that almost disappeared in recognition condition whereas AD patients exhibited a poor clustering, learning, and recognition performance, and also a high amount of false recognition; secondly, age differences as well as AD related deficits on the HOMES test were mediated by both memory and EF measure while those observed on false memory indices were only mediated by EM measure; thirdly, the HOMES indices are related to SMCs even when episodic or EF measures are controlled. Overall, the results supported the fact that the VR‐based memory test is an appropriate device to capture age‐related differences as well as the AD effect with respect to both in situ and laboratory settings.     

Visual Imagery Processing and Knowledge of Famous Names in Alzheimer's Disease and MCI

ABSTRACT

The study of memory for famous people and visual imagery retrieval was investigated in patients in the early stages of Alzheimer's disease (AD) and in the prodromal stage of AD, so-called Mild Cognitive Impairment (MCI). Fifteen patients with AD (MMSE ≥23), 15 patients with amnestic MCI (a-MCI) and 15 normal controls (NC) performed a famous names test designed to evaluate the semantic and distinctive physical features knowledge of famous persons. Results indicated that patients with AD and a-MCI generated significantly less physical features and semantic biographical knowledge about famous persons than did normal control participants. Additionally, significant differences were observed between a-MCI and AD patients in all tasks. The present findings confirm recent studies reporting semantic memory impairment in MCI. Moreover, the current findings show that mental imagery is lowered in a-MCI and AD and is likely related to the early semantic impairment.     

Parental Locus of Control and Family Functioning in the Quality of Life of Children with Sickle Cell Disease

The objective was to examine the association of parental locus of control (PLOC) with pediatric quality of life (QOL) for children with sickle cell disease (SCD), specifically addressing the potential mediating role of family functioning. Associations with disease severity were also investigated. Thirty-one primary caregivers completed standard measures of parental locus of control, family functioning, and quality of life during their child's inpatient admission for pain or fever. Results indicated that the PLOC total score was significantly associated with QOL in terms of self-competence and showed marginal significance with QOL social competence; it was significantly negatively correlated with family functioning. The association of the PLOC with QOL subscales was maintained when controlling for family functioning. Disease severity was not associated with PLOC scores. Primary caregivers endorsed more external parental locus of control beliefs. Further investigation of the association of caregiver appraisals and family functioning is warranted with the goal of addressing the stress that disease management with sickle cell may add to parent–child relationships.     

A randomized clinical trial of Behavioral Activation (BA) therapy for improving psychological and physical health in dementia caregivers: Results of the Pleasant Events Program (PEP)

Dementia caregiving is associated with elevations in depressive symptoms and increased risk for cardiovascular diseases (CVD). This study evaluated the efficacy of the Pleasant Events Program (PEP), a 6-week Behavioral Activation intervention designed to reduce CVD risk and depressive symptoms in caregivers. One hundred dementia family caregivers were randomized to either the 6-week PEP intervention (N = 49) or a time-equivalent Information-Support (IS) control condition (N = 51). Assessments were completed pre- and post-intervention and at 1-year follow-up. Biological assessments included CVD risk markers Interleukin-6 (IL-6) and D-dimer. Psychosocial outcomes included depressive symptoms, positive affect, and negative affect. Participants receiving the PEP intervention had significantly greater reductions in IL-6 (p = .040), depressive symptoms (p = .039), and negative affect (p = .021) from pre- to post-treatment. For IL-6, clinically significant improvement was observed in 20.0% of PEP participants and 6.5% of IS participants. For depressive symptoms, clinically significant improvement was found for 32.7% of PEP vs 11.8% of IS participants. Group differences in change from baseline to 1-year follow-up were non-significant for all outcomes. The PEP program decreased depression and improved a measure of physiological health in older dementia caregivers. Future research should examine the efficacy of PEP for improving other CVD biomarkers and seek to sustain the intervention's effects.