Components determining the slowness of information processing in parkinson's disease

Effects of Cognitive Training on Balance and Motor Symptoms in Parkinson's Disease: An Exploratory Randomized Controlled Trial

BackgroundCognitive rehabilitation is a potential intervention for cognitive but also motor disorders in Parkinson's disease (PD).ObjectiveTo investigate the effects of cognitive rehabilitation on balance and motor symptoms in PD.MethodsA randomized controlled trial in a community setting, in people with mild-to-moderate PD (Hoehn and Yahr ≤ III) without cognitive impairment (MoCA ≥ 24) was conducted. Thirty-nine participants were randomly allocated to receive a cognitive intervention (Experimental Group, n = 20) or no intervention (Control Group, n = 19). The experimental protocol involved self-administered cognitive rehabilitation using the NeuronUP platform, focusing on sustained attention and information processing speed training (30 min/day, 3 days/week, 4 weeks). The Berg Balance Scale (BBS) was the main outcome. Motor variables included UPDRS-III, Percentage of Limits of Stability (%LOS) and Timed Up and Go Test (TUG). Neuropsychological variables included TMT-A, TMT-B, Processing Speed (Digit Symbol-Coding and Symbol Search) and Stroop test.ResultsAt post-intervention, marginal improvements were observed in BBS (Mean Difference = 2.23 points, 95%CI [-0.03, 4.49], p = 0.053) and significant improvements in the UPDRS-III (Mean Difference = -4.02 points, 95%CI [-7.82, -0.23], p = 0.039). No significant improvements were found in the rest of the motor and cognitive variables.ConclusionsSelf-administered cognitive training did not improve balance or cognition but significantly reduced motor symptom severity in PD. The effect of more intensive or in-person cognitive rehabilitation protocols on balance needs to be evaluated.

Altered angular gyrus activation during the digit symbol substitution test in people living with HIV: beyond information processing speed deficits

Speed-of-information processing (SIP) is often impaired in people living with HIV (PLWH), typically assessed through tests such as the digit symbol (DS) and symbol search, which also rely on motor and executive functions. This study aims to disentangle SIP deficits from other cognitive impairments in PLWH using an MRI-adapted digit symbol substitution test (mDSST). Fifty-seven PLWH (34.7 ± 11.2 years) and 50 age-matched people living without HIV (PLWoH, 31.8 ± 9.9 years) completed standardized neuropsychological tests and the mDSST. Behavioral performances and brain activations were compared, with correlations drawn between group-differentiating brain activations and clinical ratings of cognitive domains. Results showed that PLWH performed worse in DS and symbol search, made fewer responses, and was slower in mDSST, with performances correlating to SIP and motor ratings. Notably, PLWH showed greater deficits in attention compared to PLWoH, rather than in SIP or motor. PLWH also exhibited greater primary motor cortex activation and reduced right angular gyrus activation. These findings suggest that slower performances on SIP-related tests in PLWH may be partially linked to abnormal visuospatial attention, as reflected by reduced angular gyrus activation, with higher motor cortex activation potentially serving as a compensatory mechanism. Future studies should explore whether prefrontal regions implicated in SIP are impaired in more severely affected PLWH.

How to optimise medicines management for people with Parkinson's disease in hospital

RATIONALE AND KEY POINTS

Hospital admissions can be challenging for people with Parkinson's disease, in part because of the lack of understanding, among some healthcare professionals, of the importance of administering antiparkinsonian medicines on time. This article outlines the steps that nurses can take to optimise medicines management for people with Parkinson's disease who are admitted to hospital. • Pharmacotherapy is the primary treatment for Parkinson's disease and aims to increase dopamine levels in the brain to relieve symptoms. • People with Parkinson's disease require careful administration, titration, adjustment and monitoring of their antiparkinsonian medicines regimen, which is highly individualised. • It is crucial that people with Parkinson's disease take their antiparkinsonian medicines at exactly the right time, since the inaccurate timing of these medicines can have significant adverse health implications. REFLECTIVE ACTIVITY: 'How to' articles can help to update your practice and ensure it remains evidence-based. Apply this article to your practice. Reflect on and write a short account of: • How this article might improve your practice when undertaking medicines management for people with Parkinson's disease in hospital. • How you could use this information to educate nursing students or your colleagues on optimising medicines management for people with Parkinson's disease in hospital.

Transcutaneous Kilohertz High-Frequency Alternating Current at 10 kHz for Upper-Limb Tremor in People with Parkinson's Disease: A Double-Blind, Randomized, Crossover Study

Background/Objectives: Preclinical studies have evidenced a peripheral nerve blockade with kilohertz high-frequency alternating current (KHFAC) stimulation. It could have a potential effect on aberrant nerve hyperactivity, such as tremor in people with Parkinson's disease (PwPD). The objective was to investigate the effects of transcutaneous KHFAC at 10 kHz compared with sham intervention on tremor modulation, upper limb motor function, and adverse events in PwPD. Methods: This randomized, double-blind, crossover trial included PwPD, who received transcutaneous KHFAC and sham interventions, within a 48 h washout period. Measurements were taken pre-intervention, during, immediately after, and 10 min post-intervention. The main outcomes were rest, postural, and kinetic tremor acceleration. Secondary outcomes were handgrip strength, nine-hole peg test (NHPT), movement onset time, and adverse events. Results: Sixteen PwPD were analyzed. Kinetic tremor diminished only in active treatment from baseline at post-intervention (-32.3% (SD 63.3); p = 0.03) and 10 min after intervention (-38.9% (SD 60.3); p = 0.03). Active treatment showed a greater reduction in kinetic tremor at post-treatment compared to sham (-58.7% SD 123; p = 0.055) close to reaching statistical significance. Only active intervention diminished movement onset time at post-intervention (-26.9% (SD 28.3); p = 0.04). Active intervention diminished handgrip strength compared to sham intervention during the stimulation (-6.6% (SD 10.0); p = 0.02). No relevant adverse effects were reported. Conclusions: KHFAC stimulation at 10 kHz appeared safe and showed potential benefits for reducing kinetic tremor in PwPD. The transient reduction in grip strength suggested an effect on alpha-motoneurons. However, further studies with larger sample sizes are necessary to confirm these findings.

Movement-related activity in the internal globus pallidus of the parkinsonian macaque

Although the basal ganglia (BG) plays a central role in the motor symptoms of Parkinson's disease, few studies have investigated the influence of parkinsonism on movement-related activity in the BG. Here, we studied the perimovement activity of neurons in globus pallidus internus (GPi) of non-human primates before and after the induction of parkinsonism by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Neuronal responses were equally common in the parkinsonian brain as seen prior to MPTP and the distribution of different response types was largely unchanged. The slowing of behavioral reaction times and movement durations following the induction of parkinsonism was accompanied by a prolongation of the time interval between neuronal response onset and movement initiation. Neuronal responses were also reduced in magnitude and prolonged in duration after the induction of parkinsonism. Importantly, those two effects were more pronounced among decrease-type responses, and they persisted after controlling for MPTP-induced changes in the trial-by-trial timing of neuronal responses. Following MPTP The timing of neuronal responses also became uncoupled from the time of movement onset and more variable from trial-to-trial. Overall, the effects of MPTP on temporal features of neural responses correlated most consistently with the severity of parkinsonian motor impairments whereas the changes in response magnitude and duration were either anticorrelated with symptom severity or inconsistent. These findings point to a potential previously underappreciated role for abnormalities in the timing of GPi task-related activity in the generation of parkinsonian motor signs.

Online cognitive monitoring technology for people with Parkinson's disease and REM sleep behavioural disorder

Automated online cognitive assessments are set to revolutionise clinical research and healthcare. However, their applicability for Parkinson's Disease (PD) and REM Sleep Behavioural Disorder (RBD), a strong PD precursor, is underexplored. Here, we developed an online battery to measure early cognitive changes in PD and RBD. Evaluating 19 candidate tasks showed significant global accuracy deficits in PD (0.65 SD, p = 0.003) and RBD (0.45 SD, p = 0.027), driven by memory, language, attention and executive underperformance, and global reaction time deficits in PD (0.61 SD, p = 0.001). We identified a brief 20-min battery that had sensitivity to deficits across these cognitive domains while being robust to the device used. This battery was more sensitive to early-stage and prodromal deficits than the supervised neuropsychological scales. It also diverged from those scales, capturing additional cognitive factors sensitive to PD and RBD. This technology offers an economical and scalable method for assessing these populations that can complement standard supervised practices.

Neuropsychological Changes in Isolated REM Sleep Behavior Disorder: A Systematic Review and Meta-analysis of Cross-sectional and Longitudinal Studies

The aim of this meta-analysis is twofold: (a) to assess cognitive impairments in isolated rapid eye movement (REM) sleep behavior disorder (iRBD) patients compared to healthy controls (HC); (b) to quantitatively estimate the risk of developing a neurodegenerative disease in iRBD patients according to baseline cognitive assessment. To address the first aim, cross-sectional studies including polysomnography-confirmed iRBD patients, HC, and reporting neuropsychological testing were included. To address the second aim, longitudinal studies including polysomnography-confirmed iRBD patients, reporting baseline neuropsychological testing for converted and still isolated patients separately were included. The literature search was conducted based on PRISMA guidelines and the protocol was registered at PROSPERO (CRD42021253427). Cross-sectional and longitudinal studies were searched from PubMed, Web of Science, Scopus, and Embase databases. Publication bias and statistical heterogeneity were assessed respectively by funnel plot asymmetry and using I2. Finally, a random-effect model was performed to pool the included studies. 75 cross-sectional (2,398 HC and 2,460 iRBD patients) and 11 longitudinal (495 iRBD patients) studies were selected. Cross-sectional studies showed that iRBD patients performed significantly worse in cognitive screening scores (random-effects (RE) model = -0.69), memory (RE model = -0.64), and executive function (RE model = -0.50) domains compared to HC. The survival analyses conducted for longitudinal studies revealed that lower executive function and language performance, as well as the presence of mild cognitive impairment (MCI), at baseline were associated with an increased risk of conversion at follow-up. Our study underlines the importance of a comprehensive neuropsychological assessment in the context of iRBD.

Cognitive Speed in Neurodegenerative Disease: Comparing Mean Rate and Inconsistency Within and Across the Alzheimer's and Lewy Body Spectra in the COMPASS-ND Study

Background

Alzheimer's disease (AD) and Lewy body disease (LBD) are characterized by early and gradual worsening perturbations in speeded cognitive responses.

Objective

Using simple and choice reaction time tasks, we compared two indicators of cognitive speed within and across the AD and LBD spectra: mean rate (average reaction time across trials) and inconsistency (within person variability).

Methods

The AD spectrum cohorts included subjective cognitive impairment (SCI, n = 28), mild cognitive impairment (MCI, n = 121), and AD (n = 45) participants. The LBD spectrum included Parkinson's disease (PD, n = 32), mild cognitive impairment in PD (PD-MCI, n = 21), and LBD (n = 18) participants. A cognitively unimpaired (CU, n = 39) cohort served as common benchmark. We conducted multivariate analyses of variance and discrimination analyses.

Results

Within the AD spectrum, the AD cohort was slower and more inconsistent than the CU, SCI, and MCI cohorts. The MCI cohort was slower than the CU cohort. Within the LBD spectrum, the LBD cohort was slower and more inconsistent than the CU, PD, and PD-MCI cohorts. The PD-MCI cohort was slower than the CU and PD cohorts. In cross-spectra (corresponding cohort) comparisons, the LBD cohort was slower and more inconsistent than the AD cohort. The PD-MCI cohort was slower than the MCI cohort. Discrimination analyses clarified the group difference patterns.

Conclusions

For both speed tasks, mean rate and inconsistency demonstrated similar sensitivity to spectra-related comparisons. Both dementia cohorts were slower and more inconsistent than each of their respective non-dementia cohorts.

Bradyphrenia and Tachyphrenia in Idiopathic Parkinsonism Appear, in Part, Iatrogenic: An Observational Study with Systematic Review Background

We question whether bradyphrenia, slowing of cognitive processing not explained by depression or a global cognitive assessment, is a nosological entity in idiopathic parkinsonism (IP). The time taken to break contact of an index finger with a touch-sensitive plate was measured, with and without a warning in the alerting signal as to which side the imperative would indicate, in 77 people diagnosed with IP and in 124 people without an IP diagnosis. The ability to utilise a warning, measured by the difference between loge-transformed reaction times (unwarned minus warned), was termed 'cognitive efficiency'. It was approximately normally distributed. A questionnaire on self- and partner perception of proband's bradyphrenia was applied. A multivariable model showed that those prescribed levodopa were less cognitively efficient (mean -5.2 (CI -9.5, -1.0)% per 300 mg/day, p = 0.02), but those prescribed the anti-muscarinic trihexyphenidyl were more efficient (14.7 (0.2, 31.3)% per 4 mg/day, p < 0.05) and those prescribed monoamine oxidase-B inhibitor (MAOBI) tended to be more efficient (8.3 (0.0, 17.4)%, p = 0.07). The variance in efficiency was greater within IP (F-test, p = 0.01 adjusted for any demographic covariates: coefficient of variation, with and without IP, 0.68 and 0.46, respectively), but not so after adjustment for anti-parkinsonian medication (p = 0.13: coefficient of variation 0.62). The within-participant follow-up time, a median of 4.8 (interquartile range 3.1, 5.5) years (101 participants), did not influence efficiency, irrespective of IP status. Perception of bradyphrenia did not usefully predict efficiency. We conclude that both bradyphrenia and 'tachyphrenia' in IP appear to have iatrogenic components, of clinically important size, related to the dose of antiparkinsonian medication. Levodopa is the most commonly prescribed first-line medication: co-prescribing a MAOBI may circumvent its associated bradyphrenia. The previously reported greater efficiency associated with (low-dose) anti-muscarinic was confirmed.

Immersive Virtual Reality Reaction Time Test and Relationship with the Risk of Falling in Parkinson's Disease

Immersive virtual reality (IVR) uses customized and advanced software and hardware to create a digital 3D reality in which all of the user's senses are stimulated with computer-generated sensations and feedback. This technology is a promising tool that has already proven useful in Parkinson's disease (PD). The risk of falls is very high in people with PD, and reaction times and processing speed may be markers of postural instability and functionality, cognitive impairment and disease progression. An exploratory study was conducted to explore the feasibility of reaction time tests performed in IVR as predictors of falls. A total of 26 volunteers (79.2% male; 69.73 ± 6.32 years) diagnosed with PD (1.54 ± 0.90 H&Y stage; 26.92 ± 2.64 MMSE) took part in the study. IVR intervention was feasible, with no adverse effects (no Simulator Sickness Questionnaire symptoms). IVR reaction times were related (Spearman's rho) to functionality (timed up and go test (TUG) (rho = 0.537, p = 0.005); TUG-Cognitive (rho = 0.576, p = 0.020); cognitive impairment mini mental state exam (MMSE) (rho = -0.576, p = 0.002)) and the years of the patients (rho = 0.399, p = 0.043) but not with the first PD symptom or disease stage. IVR test is a complementary assessment tool that may contribute to preventing falls in the proposed sample. Additionally, based on the relationship between TUG and reaction times, a cut-off time is suggested that would be effective at predicting the risk of suffering a fall in PD patients using a simple and quick IVR test.

Feasibility and Effects of an Immersive Virtual Reality Exergame Program on Physical Functions in Institutionalized Older Adults: A Randomized Clinical Trial

One of the pillars which underpins active aging is found in the performance of physical activity. While adherence to physical activity programs has traditionally been low in older people, immersive virtual reality (IVR) could provide an alternative and complementary training mode. A randomized clinical trial was conducted to explore the feasibility and effects of a 10-week IVR exergame program on physical functions of 24 institutionalized older adults who were allocated to an experimental group (EG n = 13; 85.08 ± 8.48 years) and control group (CG n = 11; 84.82 ± 8.10 years). The IVR intervention was feasible, with no adverse effects being reported (no Simulator Sickness Questionnaire symptoms; low negative experience scores on the Game Experience Questionnaire < 0.34/4), no dropouts, high adherence, and good post-gaming usability (System Usability Scale > 73.96%). The EG showed significant improvements: Tinetti scores for balance (1.84 ± 1.06; p < 0.001), gait (1.00 ± 1.08; p < 0.001), total score (2.84 ± 1.67; p < 0.001), and handgrip (4.96 ± 4.22; p < 0.001) (pre−post assessment). The CG showed significantly worsened compared to the EG: Five times sit-to-stand test, Tinetti scores for balance, gait, and total score, and the Timed Up and Go test total score (post-assessment). The findings show that the IVR intervention is a feasible method to approach a personalized exercise program and an effective way by which to improve physical function in the target population.

Cognitive deficits and clinical symptoms in patients with treatment-refractory obsessive-compulsive disorder: The role of slowness in information processing

Patients with Obsessive-Compulsive Disorder (OCD) present neuropsychological deficits across different cognitive domains, especially in executive functioning and information processing speed. Some studies have even suggested that speed deficits may underlie poor neuropsychological performance. However, this hypothesis remains unanswered in both OCD general population and OCD refractory subgroup. In addition, it is not clear whether such deficits are secondary to the clinical symptoms or may constitute a primary deficit. The aim of this study was to explore the speed of processing hypothesis in treatment-refractory OCD patients, and to clarify to what extent slowness is related to psychopathological symptoms. Both clinical and neuropsychological examination was conducted to assess 39 OCD refractory patients candidates for neurosurgery and 39 healthy matched individuals. Principal component analysis revealed a three-component structure in the neuropsychological battery being used, including a speed of processing, working memory, and conflict monitoring components. Group comparisons revealed that OCD patients performed significantly worse than healthy individuals in speed measures, but no differences were found in executive tests not influenced by time. Correlation analyses revealed a lack of association between neuropsychological and clinical measures. The results suggest that treatment-refractory OCD patients exhibit a primary deficit in information processing speed independent of clinical symptoms.

Computerized Simple Reaction Time and Balance in Nondemented Parkinson's Patients

BACKGROUND

Parkinson's disease (PD) patients are known to suffer from subtle cognitive and balance deficits from the early stages although they usually manifest in advanced stages. Postural instability (PI) has been correlated with slower information processing speed. Simple reaction time (SRT) tasks can be used to measure the speed of information processing. The main objective of this study was to examine the usefulness of SRT as a valid predictor of balance in PD, thus providing a simple and complementary assessment method.

METHODS

This cross-sectional study included 52 PD patients without dementia who were evaluated for balance using the pull test (PT) maneuver and Biodex® limits of stability (LOS). In addition, a reaction time task was used to measure processing speed. Correlation and linear regression analyses were performed.

RESULTS

The performance of SRT tasks was correlated with the evaluation of LOS% and PT, suggesting that the SRT may be a predictor of balance performance. Longer reaction time and poorer postural stability were also associated with disease duration but not with age.

CONCLUSIONS

Poor performance in a simple reaction task can predict altered PI and can complement staging and evaluation in PD patients.

Validation of Cognitive Rehabilitation as a Balance Rehabilitation Strategy in Patients with Parkinson's Disease: Study Protocol for a Randomized Controlled Trial

Background: Parkinson's disease (PD) is the second most common neurodegenerative disorder. This disease is characterized by motor symptoms, such as bradykinesia, tremor, and rigidity. Although balance impairment is characteristic of advanced stages, it can be present with less intensity since the beginning of the disease. Approximately 60% of PD patients fall once a year and 40% recurrently. On the other hand, cognitive symptoms affect up to 20% of patients with PD in early stages and can even precede the onset of motor symptoms. There are cognitive requirements for balance and can be challenged when attention is diverted or reduced, linking a worse balance and a higher probability of falls with a slower cognitive processing speed and attentional problems. Cognitive rehabilitation of attention and processing speed can lead to an improvement in postural stability in patients with Parkinson's. Methods: We present a parallel and controlled randomized clinical trial (RCT) to assess the impact on balance of a protocol based on cognitive rehabilitation focused on sustained attention through the NeuronUP platform (Neuronup SI, La Rioja, Spain) in patients with PD. For 4 weeks, patients in the experimental group will receive cognitive therapy three days a week while the control group will not receive any therapy. The protocol has been registered at trials.gov NCT04730466. Conclusions: Cognitive therapy efficacy on balance improvement may open the possibility of new rehabilitation strategies for prevention of falls in PD, reducing morbidity, and saving costs to the health care system.

Components determining the slowness of information processing in parkinson's disease

INTRODUCTION

Bradyphrenia is a key cognitive feature in Parkinson's disease (PD). There is no consensus on whether information processing speed is impaired or not beyond motor performance.

OBJECTIVE

This study aims to explore which perceptual, motor, or cognitive components of information processing are involved in the slowdown affecting cognitive performance.

METHODS

The study included 48 patients with PD (age: 63, 3 ± 8, 18; HY I-III; UPDRS 15,46 ± 7,76) and 53 healthy controls (age: 60,09 ± 12,83). Five reaction time (RT) tasks were administered to all participants. The average RT in each of the tasks and the percentage of correct answers were measured. Patients with PD were in "ON state" at the time of the evaluation. Perceptual, motor, and cognitive components were isolated by means of a series of ANCOVAs.

RESULTS

As expected, the motor component was slowed down in patients with PD. Moreover, while patients with PD showed slower RT than controls in all tasks, differences between groups did not exponentially increase with the increasing task complexity. ANCOVA analyses also revealed that the perceptual and sustained alert component resulted to be slowed down, with no differences being found in any of the remaining isolated cognitive components (i.e., response strategy-inhibition, decisional, visual search, or interference control).

CONCLUSIONS

The results revealed that slowness of information processing in PD was mainly associated with an impaired processing speed of the motor and perceptual-alertness components analyzed. The results may help designing new neurorehabilitation strategies, focusing on the improvement of perceptual and alertness mechanisms.