COMT基因Val158Met多态性与抑郁的关系

抑郁的发生具有重要的遗传学基础。COMT基因Val158Met多态性是抑郁的重要候选基因位点。目前有关COMT基因Val158Met多态性与抑郁关系的研究主要采用单基因设计、单基因-环境设计以及多基因-环境设计。有资料显示负性情绪偏向及其相关脑区可能在COMT基因Val158Met多态性与抑郁间起中介作用, 但具体机制仍有待探究。未来研究可以进一步考察被试的种族、年龄和性别等因素对COMT基因Val158Met多态性与抑郁关系的调节作用, 并通过采用多基因-环境设计, 综合运用积极与消极环境指标等措施深入考察负性情绪偏向和相关脑区在COMT基因Val158Met多态性与抑郁间的作用及其机制。     

Context-Dependent Learning in People With Parkinson's Disease

Context-dependent learning is a phenomenon in which people demonstrate superior performance in the context in which they originally learned a skill but perform less well in a novel context. This study investigated context-dependent learning in people with Parkinson's disease (PD) and age-matched nondisabled adults. All participants practiced 3 finger sequences, each embedded within a unique context (colors and locations on a computer screen). One day after practice, the participants were tested either under the sequence-context associations remained the same as during practice, or the sequence-context associations were changed (SWITCH). Compared with nondisabled adults, people with PD demonstrated significantly greater decrement in performance (especially movement time) under the SWITCH condition, suggesting that individuals with PD are more context dependent than nondisabled adults.     

COMT基因Val158Met多态性与同伴关系对青少年抑郁的影响

以1048名汉族青少年为被试,采用问卷法和基因分型技术,综合运用传统回归分析和新兴的再参数化回归分析,考察COMT基因Val158Met多态性与同伴关系对青少年抑郁的交互作用模式及其性别差异。结果发现,COMT基因与同伴接纳和同伴拒绝交互预测青少年抑郁,具体表现为,在低同伴接纳或高同伴拒绝环境中,携带ValVal基因型的青少年抑郁水平高于Met等位基因携带者;在高同伴接纳或低同伴拒绝环境中,携带ValVal基因型的青少年抑郁水平低于Met等位基因携带者。此外,COMT基因与同伴接纳和同伴拒绝的交互作用与男生抑郁的关联更加密切。结果显示,COMT基因与同伴关系的交互效应为不同易感性模型提供了证据,而且该基因×环境交互效应存在性别差异。     

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.     

Retention of Implicit Sequence Learning in Persons Who Stutter and Persons With Parkinson's Disease

ABSTRACT. The authors investigated the retention of implicit sequence learning in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS), and 14 control participants. Participants completed a nonsense syllable serial reaction time task in a 120-min session. Participants named aloud 4 syllables in response to 4 visual stimuli. The syllables formed a repeating 8-item sequence not made known to participants. After 1 week, participants completed a 60-min retention session that included an explicit learning questionnaire and a sequence generation task. PPD showed retention of general learning equivalent to controls but PWS's reaction times were significantly slower on early trials of the retention test relative to other groups. Controls showed implicit learning during the initial session that was retained on the retention test. In contrast, PPD and PWS did not demonstrate significant implicit learning until the retention test suggesting intact, but delayed, learning and retention of implicit sequencing skills. All groups demonstrated similar limited explicit sequence knowledge. Performance differences between PWS and PPD relative to controls during the initial session and on early retention trials indicated possible dysfunction of the cortico-striato-thalamo-cortical loop. The etiological implications for stuttering, and clinical implications for both populations, of this dysfunction are discussed.     

Beyond the Tremors: What Counselors Should Know About the Mental Health Needs of Clients Diagnosed With Parkinson's Disease

Parkinson's disease (PD) is the 2nd most common neurodegenerative disorder, affecting 1% to 4% of people by age 80 (Black, 2011 ). However, co‐occurring psychological disorders, such as depression, anxiety, and apathy, are significantly underdiagnosed. Professional counselors are uniquely qualified to assist clients with these mental health complications of PD.     

Mental and Motor Switching in Parkinson's Disease

Switching difficulties in Parkinson's disease (PD) are expressed in both mental and motor tasks. The authors of the present study investigated whether those deficits coexist in the same patient and are positively correlated. They tested 8 nondemented PD patients and 6 age-matched control participants by using the modified Wisconsin Card Sorting Test and a motor switching paradigm that is based on the task of reaching toward visual targets, the location of which could unexpectedly be altered within the reaction time. In both mental and motor tasks, patients performed significantly worse than controls. There were no significant correlations between the two types of pathology in individual patients. Mental and motor switching deteriorate in PD patients, but the deficits are not necessarily of parallel severity.

basal ganglia     

Evidence of Incomplete Motor Programming in Parkinson's Disease

One of the essential questions regarding movement deficits in Parkinson's disease (PD) is whether they stem from impaired selecting and switching among movements, impaired use of predictive information to prepare movement, or impaired execution of movement. PD subjects (n = 9) and age-matched control subjects (n = 8) performed a cued, sequential-response RT task. The cue provided either no information, accurate information, or inaccurate information about the upcoming response. PD subjects used predictive information to prepare and to switch among movement sequences normally, but second and third key press latencies were prolonged in comparison with the first key press latency. In Experiments 2 and 3, the effects of choice set and sequence length on key press latencies were examined. These results provide evidence that PD subjects initiate movement before the entire response sequence is prepared. PD does not impair motor programming or execution processes themselves but impairs the smooth coordination of those processes.     

Verbal Implicit Sequence Learning in Persons Who Stutter and Persons With Parkinson's Disease

The authors investigated the integrity of implicit learning systems in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS), and 14 control participants. In a 120-min session participants completed a verbal serial reaction time task, naming aloud 4 syllables in response to 4 visual stimuli. Unbeknownst to participants, the syllables formed a repeating 8-item sequence. PWS and PPD demonstrated slower reaction times for early but not late learning trials relative to controls reflecting delays but not deficiencies in general learning. PPD also demonstrated less accuracy in general learning relative to controls. All groups demonstrated similar limited explicit sequence knowledge. Both PWS and PPD demonstrated significantly less implicit sequence learning relative to controls, suggesting that stuttering may be associated with compromised functional integrity of the cortico-striato-thalamo-cortical loop.     

Evaluating the Acute Contributions of Dopaminergic Replacement to Gait With Obstacles in Parkinson's Disease

The influence of dopaminergic replacement (DR) on gait in people with Parkinson's disease (PD) is well documented. However, little is known about the acute effects of dopamine on more complex locomotor tasks that require visual guidance to avoid obstacles during gait. The authors investigated the influence of DR on locomotor behavior in a task where movement planning and control might be challenged by the height of the obstacle. The PD group included patients diagnosed with idiopathic PD (n = 12), as well as healthy controls (n = 12). Patients walked and stepped over obstacles of different heights before (OFF) and after (ON) levodopa intake. Spatial adjustments were not modulated by DR, but the step time to perform these anticipatory gait adjustments was longer only in PD-OFF (compared with healthy controls) when approaching the highest obstacle, but not PD-ON. During the crossing phase, trail limb toe clearance of PD patients was shorter than healthy controls only during the OFF state. ON-OFF comparisons were significantly different only for the time to reach the lead foot clearance over the highest obstacle. In summary, DR partially improved movement slowness but did not directly affect movement amplitude of lower limb regulation in this gait task.     

The Effects of Adapted Tango on Spatial Cognition and Disease Severity in Parkinson's Disease

The authors determined effects of community-based adapted tango on spatial cognition and disease severity in Parkinson's disease (PD) while controlling for the effects of social interaction. Thirty-three individuals with mild-to-moderate PD (stage I–III) were assigned to twenty 90-min tango (n = 24) or education (n = 9) lessons over 12 weeks. Disease severity, spatial cognition, balance, and fall incidence were evaluated pre-, post-, and 10–12 weeks postintervention. The authors evaluated differences using t tests and analyses of variance. Twenty-three tango and 8 education participants finished. Tango participants improved on disease severity (p = .008), and spatial cognition (p = .021) compared with education participants. Tango participants also improved in balance (p = .038), and executive function (p = .012). Gains were maintained 10–12 weeks postintervention. Multimodal exercise with structured syllabi may improve disease severity and spatial cognition in PD.     

Brief Cognitive Behavioral Therapy for Insomnia in Parkinson's Disease: A Case Series Study1

Parkinson's disease (PD) patients frequently suffer from insomnia and insomnia can result in reduction of quality of life in PD. Although pharmacotherapy is most applicable for insomnia, it may cause side-effects in PD. The purpose of the study was to investigate the efficacy of brief cognitive behavioral therapy for insomnia (CBTI) in PD. A total of 11 PD patients aged 43–84 years with chronic insomnia received two sessions of CBTI. Patients reported a significant decrease in total score for the Insomnia Severity Index (ISI). The total score for the Parkinson's Disease Sleep Scale (PDSS) improved. Although objective sleep measured by actigraph did not improve, subjective sleep measured by sleep diary improved. Functional impairment measured by the Sheehan Disability Scale (SDS) significantly decreased. These results revealed that brief CBTI was effective in improving insomnia in PD, with improvements extending to functional impairments that had been affected by insomnia. Additionally, this non-pharmacotherapy treatment could be easily applied to PD patients who may have difficulty coming to the clinic frequently due to physical symptoms.     

Interference Effects from Observed Movement in Parkinson's Disease

Previous research has demonstrated that Parkinson's disease patients have an increased susceptibility to response conflict. In the present study, the authors investigate whether Parkinson's patients have a similar sensitivity to interference from observed movements. In all, 10 patients and 10 controls performed horizontal and vertical arm movements while watching a video of either a person performing similar movements or a moving dot. Movements were performed in the same plane (congruent) and orthogonal to the observed movement (incongruent). The off-axis variance of movements was our index of interference. Although patients tended to exhibit more off-axis variability than did controls, both groups demonstrated similar congruence effects, with greater variance in incongruent conditions. These results indicated that increased susceptibility to interference in Parkinson's disease does not extend to interference from observed movements.     

Testing the dopamine overdose hypothesis in action control: A study in people with Parkinson's disease

Prior work on patients with Parkinson's disease (PD) has shown that the administration of dopaminergic medication in the early to intermediate stages of PD benefits (motor) functions associated with the dopamine-depleted dorsal striatal circuitry but may ‘overdose’ and interfere with (cognitive) functions associated with the relatively intact ventral striatal circuitry. The present study aimed to elucidate this so-called dopamine overdose hypothesis for the action control domain. Using a within-subject design in a sample of 13 people with PD, we evaluated the effect of dopaminergic medication on two cognitive processes underlying goal-directed behaviour, namely action selection and initiation through event binding and conflict adaptation. We also investigated whether individual differences in the magnitude of medication effects were associated across these processes. Results showed no indications that dopaminergic medication affects action selection and initiation or conflict adaptation in PD patients. Additionally, we observed no correlations between both cognitive processes nor between individual differences in medication effects. Our findings do not support the notion that dopaminergic medication modulates action control processes, suggesting that the dopamine overdose hypothesis may only apply to a specific set of cognitive processes and should potentially be refined.     

Treadmill Gait Analysis Characterizes Gait Alterations in Parkinson's Disease and Amyotrophic Lateral Sclerosis Mouse Models

The effect of anxiety on learning and performance of a complex motor task was determined. In addition the effects of two stressors—competition and failure—and the interactions between these stressors and anxiety were investigated. 40 high and 40 low anxiety Ss (selected by the Taylor Manifest Anxiety Scale) learned and performed a coincident timing task. Competition was presented by offering the Ss a monetary reward for the best performance, while failure was manipulated by giving false knowledge of results and indicating that the performance level was inferior. Results showed that Ss low in anxiety performed significantly better than Ss high in anxiety during the initial learning of a complex motor task. No difference was found between Ss extreme in anxiety once the task was well-learned. Competition and failure did not affect performance or interact with the anxiety level of Ss.     

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.     

Mechanisms underlying corruption of working memory in Parkinson's disease

Working memory (WM) impairments are reported to occur in patients with Parkinson's disease (PD). However, the mechanisms are unclear. Here, we investigate several putative factors that might drive poor performance, by examining the precision of recall, the order in which items are recalled and whether memories are corrupted by random guessing (attentional lapses). We used two separate tasks that examined the quality of WM recall under different loads and retention periods, as well as a traditional digit span test. Firstly, on a simple measure of WM recall, where patients were asked to reproduce the orientation of a centrally presented arrow, overall recall was not significantly impaired. However, there was some evidence for increased guessing (attentional lapses). On a new analogue version of the Corsi-span task, where participants had to reproduce on a touchscreen the exact spatial pattern of presented stimuli in the order and locations in which they appeared, there was a reduction in the precision of spatial WM at higher loads. This deficit was due to misremembering item order. At the highest load, there was reduced recall precision, whereas increased guessing was only observed at intermediate set sizes. Finally, PD patients had impaired backward, but not forward, digit spans. Overall, these results reveal the task- and load-dependent nature of WM deficits in PD. On simple low-load tasks, attentional lapses predominate, whereas at higher loads, in the spatial domain, the corruption of mnemonic information—both order item and precision—emerge as the main driver of impairment.     

Decomposition of warning effects in Parkinson's disease

ABSTRACT

Neutral warning signals speed voluntary reactions by reducing temporal uncertainty and by triggering a brief burst of arousal. We attempted to isolate the phasic arousal mechanism in people with Parkinson's disease (PD) using a clock display to minimize temporal uncertainty. In this condition, the speeding of responses in a color-discrimination task by an accessory stimulus was the fully equivalent to the effect in age-matched control subjects. This indicates preserved phasic arousal in PD. Temporal preparation based on warning cues also appeared to be normal. By contrast, in a condition with high temporal uncertainty, the accessory stimulus (an air puff to the foot) impaired accuracy for the patients but not the neurologically normal subjects. The data are consistent with the view that PD disrupts internal but not external control of alertness.     

The Caregivers' Attachment and Relationship Education Class: A New and Promising Group Therapy for Caregivers of Individuals with Parkinson's Disease

The authors examined whether a newly developed group therapy, based on principles of attachment theory and emotionally focused couples therapy, can potentially address the unique mental health and relationship difficulties in caregivers of individuals with Parkinson's disease. A comprehensive outreach effort, involving a review of 251 military veterans' medical records, yielded enrollment of seven spousal caregivers in the group therapy. At 1-month follow-up, caregivers who initially reported mild or greater levels of caregiver burden demonstrated statistically reliable declines in psychological distress, relationship distress, or both. Posttreatment surveys indicated positive perceptions in overall helpfulness of treatment goals, as well as positive changes in insight (e.g., greater understanding of the patient's attachment needs) and behaviors (e.g., greater social contact and self-care of the caregiver). Results are considered in the context of inadequate access to treatment for caregivers of spouses with Parkinson's disease or other major medical issues.     

The Relationship between Contrast Sensitivity,Gait, and Reading Speed in Parkinson's Disease

ABSTRACT

Parkinson's disease (PD) results in reduced walking speed and visual difficulties, including difficulty reading (Davidsdottir, Cronin-Golomb, & Lee, 2005 Davidsdottir, S., Cronin-Golomb, A. and Lee, A. 2005. Visual and spatial symptoms in Parkinson's disease. Vision Research, 45: 1285–1296. [Crossref] , [Google Scholar]). PD is characterized by a reduction in dopamine, which is instrumental in determining a person's contrast sensitivity (CS). This study assessed the relationship between CS, gait (step length and walking speed), and reading speed in 18 non-demented PD volunteers with normal acuity. We found that CS correlated with walking speed (r = .57, p = .01), step length (r = .53, p = .02), and reading speed (r = .54, p = .02). Visual acuity (which has not been tied to dopamine in the same way) correlated with reading speed (r_s = –.65, p = .004), but not with gait measures. We also assessed the contribution of age, education, and cognitive status (Shipley Institute of Living Scale) to these variables. We conclude that CS and age both play an important role in determining gait in PD, while reading speed is related to both acuity and CS, but not age.