Cognition in movement disorders: where can we hope to be in ten years?

Efficacy and Feasibility of the CO-OP Approach in Parkinson's Disease: RCT Study Protocol

Background. Parkinson's disease (PD) leads to cognitive dysfunction which limits participation and occupational performance. Cognitive Orientation to Daily Occupational Performance (CO-OP) approach is effective in other adult neurological populations and warrants investigation in PD. Purpose. To describe a study protocol evaluating the preliminary efficacy and feasibility of CO-OP approach in PD. Method. A randomised controlled trial (RCT) with adults with PD was assigned to either: CO-OP training-intensive (CO-OP-I, 20 sessions) or waitlist control (WLC) followed by CO-OP-standard (CO-OP-S, 10 sessions). Outcomes. Occupational performance and satisfaction of adults with PD in chosen goals. Measures will be obtained at baseline, post-intervention, and 3-month follow-up. Implications. As the first RCT focused on CO-OP in PD, this trial will provide evidence for the potential of this approach in PD and lay the groundwork for future large-scale trials. Trial Registration. Australian New Zealand Clinical Trials registry, ACTRN12621001483842. Registered November 1, 2021; retrospectively registered 3 months after commencement.

Person-centered goal setting is feasible in people with Parkinson's disease who have subjective cognitive decline: a mixed methods study

PURPOSE

Evaluate the feasibility of person-centered goal setting in people with Parkinson's disease (PD) who have subjective cognitive decline and explore characteristics of the formulated goals.

MATERIALS AND METHODS

Participants completed person-centered goal setting as a part of two cognitive intervention studies. Participants were guided to develop at least three goals and rate the importance of each goal using a 10-point scale (1: not at all important - 10: extremely important). To evaluate the feasibility of person-centered goal setting, we calculated the mean number of formulated goals per person and the importance level of all goals. To explore goal characteristics, two independent authors coded all goals and synthesized them using deductive content analysis in consultation with the senior author.

RESULTS

Thirty participants formulated a total of 166 goals. The mean number of formulated goals per participant was 5.53 (SD = 2.22, range = 3 - 10). The mean importance level of all formulated goals was 8.3 (SD = 1.49, range = 4 - 10). Formulated goals ranged across diverse domains and categories.

CONCLUSIONS

Person-centered goal setting is feasible to guide people with PD to formulate personally meaningful goals. Findings highlight the diverse cognitive rehabilitation needs of people with PD, potential cognitive rehabilitation priorities, and future goal setting research directions.Implications for rehabilitationRehabilitation clinicians and researchers should not assume that people with PD who have subjective cognitive decline are not capable of engaging in their goal setting.Rehabilitation clinicians and researchers should acknowledge and act on our responsibility to enable people with PD who have subjective cognitive decline to engage in goal setting.Rehabilitation clinicians and researchers are encouraged to explore diverse goal domains to optimize goal setting and rehabilitation care among people with PD who have subjective cognitive decline.

The Weekly Calendar Planning Activity to Assess Functional Cognition in Parkinson Disease

The Weekly Calendar Planning Activity (WCPA) may improve understanding of functional cognition in people with Parkinson disease (PwPD) without dementia. We aimed to determine if WCPA performance (a) discriminates between PwPD with and without cognitive impairment and healthy controls and (b) correlates with other indicators of cognition and daily function. This was a cross-sectional study. Parkinson disease (PD) participants without dementia were divided into normal cognition (PD-NC, n = 25) and possible mild cognitive impairment (PD-MCI, n = 21) groups. Their WCPA performance was compared with that of a normative sample (n = 196) and correlated with neuropsychological test performance and self-reported cognition and participation. Both the PD-MCI and PD-NC groups had impaired WCPA performance. WCPA performance correlated with executive function, processing speed, and self-reported cognition and participation. The WCPA can detect functional cognitive deficits in PwPD without dementia and can inform occupational therapy interventions to support functional cognition, occupational performance, and participation in this population.

Cognitive Correlates of Instrumental Activities of Daily Living Performance in Parkinson Disease Without Dementia

OBJECTIVE

To investigate cognitive correlates of instrumental activities of daily living (IADL) performance among people with Parkinson disease (PD) without dementia.

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PARTICIPANTS

Volunteer sample (N=161) comprising participants with PD without dementia (n=102) and healthy comparison (HC) participants (n=59).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Performance-based assessment of cognitively-demanding IADL (meal preparation, bill paying, shopping, medication management, small home repair), neuropsychological tests (attentional control/flexibility, planning, working memory, memory, crystallized intelligence), and measures of motor function and other characteristics (eg, depressive symptoms).

RESULTS

There were no group differences in neuropsychological test performance (P>.06). The PD group performed more poorly than the HC group on a number of cognitive IADL tasks (P<.04). After accounting for the effects of motor impairment and other disease-related characteristics, neuropsychological test performance accounted for a small but unique portion of the variance in performance of all cognitive IADL combined, meal preparation, shopping, and medication management in the PD group (R 2=4%-13%; P≤.01).

CONCLUSIONS

The PD group had cognitive IADL performance limitations despite being unimpaired on neuropsychological tests. Within PD, neuropsychological test performance accounted for a small but significant portion of the variance in cognitive IADL performance over and above the effects of motor and other impairments. These results support the added value of using performance-based IADL assessments in functional evaluations of individuals with early and mild PD without dementia.

Cognitive profile in Restless Legs Syndrome: A signal-to-noise ratio account

Restless legs syndrome (RLS) is a common neurological disorder characterized by a sensorimotor condition, where patients feel an uncontrollable urge to move the lower limbs in the evening and/or during the night. RLS does not only have a profound impact on quality of life due to the disturbed night-time sleep, but there is growing evidence that untreated or insufficiently managed RLS might also cause cognitive changes in patients affected by this syndrome. It has been proposed that RLS is caused by alterations in the signal-to-noise ratio (SNR) and in dopamine (DA) neurotransmission in the nervous system. Based on this evidence, we propose the “SNR-DA hypothesis” as an explanation of how RLS could affect cognitive performance. According to this hypothesis, variations/reductions in the SNR underlie RLS-associated cognitive deficits, which follow an inverted U-shaped function: In unmedicated patients, low dopamine levels worsen the SNR, which eventually impairs cognition. Pharmacological treatment enhances DA levels in medicated patients, which likely improves/normalizes the SNR in case of optimal doses, thus restoring cognition to a normal level. However, overmedication might push patients past the optimal point on the inverted U-shaped curve, where an exaggerated SNR potentially impairs cognitive performance relying on cortical noise such as cognitive flexibility. Based on these assumptions of SNR alterations, we propose to directly measure neural noise via “1/f noise” and related metrics to use transcranial random noise stimulation (tRNS), a noninvasive brain stimulation method which manipulates the SNR, as a research tool and potential treatment option for RLS.

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Restless legs syndrome (RLS) is a common neurological disorder.

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RLS is caused by alterations in the SNR ratio and in DA neurotransmission.

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The SNR- DA hypothesis how RLS affects cognitive performance is presented.

An increased rate of longitudinal cognitive decline is observed in Parkinson's disease patients with low CSF Aß42 and an APOE ε4 allele

OBJECTIVE

Low concentrations of cerebrospinal fluid (CSF) amyloid-beta (Aβ-42) are associated with increased risk of cognitive decline in Parkinson's disease (PD). We sought to determine whether APOE genotype modifies the rate of cognitive decline in PD patients with low CSF Aβ-42 compared to patients with normal levels.

METHODS

The Parkinson's Progression Markers Initiative is a longitudinal, ongoing study of de novo PD participants, which includes APOE genotyping, CSF Aβ-42 determinations, and neuropsychological assessments. We used linear mixed effects models in three PD groups (PD participants with low CSF Aβ at baseline, PD participants with normal CSF Aβ, and both groups combined). Having at least one copy of the APOE ɛ4 allele, time, and the interaction of APOE ɛ4 and time were predictor variables for cognitive change, adjusting for age, gender and education.

RESULTS

423 de novo PD participants were followed up to 5 years with annual cognitive assessments. 103 participants had low baseline CSF Aβ-42 (39 APOE ε4+, 64 APOE ε4-). Compared to participants with normal CSF Aβ-42, those with low CSF Aβ-42 declined faster on most cognitive tests. Within the low CSF Aβ-42 group, APOE ε4+ participants had faster rates of decline on the Montreal Cognitive Assessment (primary outcome; 0.57 points annual decline, p = .005; 5-year standardized change of 1.2) and the Symbol Digit Modalities Test (1.4 points annual decline, p = .002; 5-year standardized change of 0.72).

DISCUSSION

PD patients with low CSF Aβ-42 and APOE ε4+ showed a higher rate of cognitive decline early in the disease. Tests of global cognition (Montreal Cognitive Assessment) and processing speed (Symbol Digit Modalities Test) were the most sensitive to early cognitive decline. Results suggest that CSF Aβ-42 and APOE ε4 might interact to promote early cognitive changes in PD patients.

Encoding strategy training and self-reported everyday prospective memory in people with Parkinson disease: a randomized-controlled trial

Objective To compare the effects of laboratory-based training in implementation intentions (II; experimental strategy) and verbal rehearsal (VR; control strategy) on self-reported everyday prospective memory among people with Parkinson disease (PD) and to investigate potential correlates of change in self-reported everyday prospective memory in response to this training. Method This was a randomized-controlled trial. Participants with mild to moderate PD without dementia underwent one session of training in either II (n = 25) or VR (n = 27). Then they were instructed to use their strategy as much as possible in their everyday lives to help them remember to do things. The Prospective and Retrospective Memory Questionnaire Prospective Scale (PRMQ-Pro) administered at baseline and one month after training assessed training-related change in self-reported everyday prospective memory. Baseline depressive symptoms, perceptions of the strategy (credibility, expectancy), prospective memory-related awareness, global cognition, and disease severity were correlated to PRMQ-Pro Change scores (post minus pre) to determine their association with response to training. Results The VR group's PRMQ-Pro scores declined from pre to post training, while the II group's remained stable (p = .03). This effect was driven by change in self-cued everyday prospective memory tasks. Higher baseline depressive symptoms, treatment expectancy, and global cognition related to better response to training in the II group (rs ≤ -.40, ps ≤ .05). Conclusions II training may prevent everyday prospective memory decline among people with PD. In addition, people with higher depression, stronger expectations of improvement from strategy training, or better global cognition may benefit the most from II training.

Feasibility of a cognitive strategy training intervention for people with Parkinson's disease

PURPOSE

To investigate the feasibility of a novel client-centered cognitive strategy training intervention for people with Parkinson's disease (PD).

MATERIALS AND METHODS

This was a case series of seven people with PD without dementia but with subjective cognitive decline. The intervention involved ≥5 treatment sessions at the participant's home. Participant acceptance and engagement were assessed by the Credibility/Expectancy Questionnaire (CEQ), Client Satisfaction Questionnaire (CSQ), enjoyment and effort ratings, and homework completion. Logistical information was tracked, and the Canadian Occupational Performance Measure (COPM) was an exploratory outcome measure. Data analysis was descriptive.

RESULTS

CEQ scores were positive and increased over time. CSQ scores were high (M = 30.8, SD = 0.75), with all participants rating all items positively. Almost all (95%) effort and enjoyment ratings were ≥3 (Much), and homework completion rates averaged 84% (SD = 18). Intervention duration was 6-15 weeks (M = 9.2, SD = 2.8), with treatment sessions averaging 1.7 h (SD = 0.5). Group and most individual COPM ratings improved ≥2 points.

CONCLUSIONS

These findings support the feasibility of the intervention for people with PD. It was acceptable, engaging, and promising in terms of its effect on self-identified functional cognitive problems. Implications for Rehabilitation People with Parkinson's disease (PD) without dementia can experience cognitive decline that negatively impacts function and quality of life. Strategy-based interventions that explicitly train for transfer may mitigate the negative functional consequences of cognitive decline in this population. We developed a client-centered cognitive strategy training intervention for people with PD. This small case series supports its feasibility, indicating that it is acceptable and engaging for people with PD and promising in terms of its effect on self-identified functional cognitive problems.

Overview of Neurocognitive Disorders

Cognitive function is a major determinant of an individual's quality of life. However, the number of individuals developing a neurocognitive disorder (NCD) is increasing as the population ages: the number of individuals with dementia is doubling every 20 years and will reach over 115 million worldwide by 2050. There is a need to identify vulnerable individuals early, understand the trajectory of their NCD, and intervene with effective treatments. The DSM-5 outlines criteria to identify patients with mild NCD and distinguish them from patients with major NCD. Identifying patients early in the course of a dementing disorder can improve the opportunity to develop effective interventions to change the course of the NCD. Research is needed to identify biomarkers and risk factors that indicate an individual's potential for developing an NCD.

Parkinson's Disease: Cognitive Impairment

Cognitive deficits are important and emerging clinical targets for psychiatrists caring for patients with Parkinson's disease (PD), a neurodegenerative disorder commonly accompanied by mood and psychotic disturbances and identified by its progressive motor abnormalities. Over the course of the disease and across all its stages, virtually every individual with PD experiences some degree of cognitive deficit, ranging from mild cognitive impairment to dementia. Across this spectrum, cognitive impairments affect functioning and quality of life, often more than motor aspects of the disease. Advances in treatments for motor deficits in PD now render the clinical significance of cognitive dysfunction more obvious, including its impact on psychiatric presentations and their treatment. Since cognitive dysfunction is underdetected and undertreated in clinical practice, holistic psychiatric care of PD patients warrants appreciation of the clinical presentation, biopsychosocial features, and treatment of cognitive impairment. Future directions for research and clinical care also discussed.

Nonpharmacological treatments for patients with Parkinson's disease

Since 2013, a number of studies have enhanced the literature and have guided clinicians on viable treatment interventions outside of pharmacotherapy and surgery. Thirty-three randomized controlled trials and one large observational study on exercise and physiotherapy were published in this period. Four randomized controlled trials focused on dance interventions, eight on treatment of cognition and behavior, two on occupational therapy, and two on speech and language therapy (the latter two specifically addressed dysphagia). Three randomized controlled trials focused on multidisciplinary care models, one study on telemedicine, and four studies on alternative interventions, including music therapy and mindfulness. These studies attest to the marked interest in these therapeutic approaches and the increasing evidence base that places nonpharmacological treatments firmly within the integrated repertoire of treatment options in Parkinson's disease.

Parkinson's disease dementia: a neural networks perspective

In the long-term, with progression of the illness, Parkinson's disease dementia affects up to 90% of patients with Parkinson's disease. With increasing life expectancy in western countries, Parkinson's disease dementia is set to become even more prevalent in the future. However, current treatments only give modest symptomatic benefit at best. New treatments are slow in development because unlike the pathological processes underlying the motor deficits of Parkinson's disease, the neural mechanisms underlying the dementing process and its associated cognitive deficits are still poorly understood. Recent insights from neuroscience research have begun to unravel the heterogeneous involvement of several distinct neural networks underlying the cognitive deficits in Parkinson's disease dementia, and their modulation by both dopaminergic and non-dopaminergic transmitter systems in the brain. In this review we collate emerging evidence regarding these distinct brain networks to give a novel perspective on the pathological mechanisms underlying Parkinson's disease dementia, and discuss how this may offer new therapeutic opportunities.