How do cognitive and axial motor signs correlate in Parkinson’s disease? A 6-year prospective study

Levodopa may modulate specific speech impairment in Parkinson's disease: an fMRI study

Hypokinetic dysarthria (HD) is a difficult-to-treat symptom affecting quality of life in patients with Parkinson's disease (PD). Levodopa may partially alleviate some symptoms of HD in PD, but the neural correlates of these effects are not fully understood. The aim of our study was to identify neural mechanisms by which levodopa affects articulation and prosody in patients with PD. Altogether 20 PD patients participated in a task fMRI study (overt sentence reading). Using a single dose of levodopa after an overnight withdrawal of dopaminergic medication, levodopa-induced BOLD signal changes within the articulatory pathway (in regions of interest; ROIs) were studied. We also correlated levodopa-induced BOLD signal changes with the changes in acoustic parameters of speech. We observed no significant changes in acoustic parameters due to acute levodopa administration. After levodopa administration as compared to the OFF dopaminergic condition, patients showed task-induced BOLD signal decreases in the left ventral thalamus (p = 0.0033). The changes in thalamic activation were associated with changes in pitch variation (R = 0.67, p = 0.006), while the changes in caudate nucleus activation were related to changes in the second formant variability which evaluates precise articulation (R = 0.70, p = 0.003). The results are in line with the notion that levodopa does not have a major impact on HD in PD, but it may induce neural changes within the basal ganglia circuitries that are related to changes in speech prosody and articulation.

Semantic fluency deficits and associated brain activity in Parkinson's disease with mild cognitive impairment

People living with Parkinson's disease (PD) with poor verbal fluency have an increased risk of developing dementia. This study examines the neural mechanisms underpinning semantic fluency deficits in patients with PD with mild cognitive impairment (PD-MCI) compared to those without MCI (PD-NC) and control participants without PD (non-PD). Thirty-seven (37) participants with PD completed a cognitive assessment battery to identify MCI (13 PD-MCI). Twenty sex- and age-matched non-PD patients also participated. Participants were scanned (3T Siemens PRISMA) while performing semantic fluency, semantic switching, and automatic speech tasks. The number of responses and fMRI data for semantic generation and semantic switching were analyzed. Participants also completed a series of verbal fluency tests outside the scanner, including letter fluency. Participants with PD-MCI performed significantly worse than PD-NC and non-PD participants during semantic fluency and semantic switching tasks. PD-MCI patients showed greater activity in the right angular gyrus than PD-NC and non-PD patients during semantic switching. Increased right angular activity correlated with worse verbal fluency performance outside the scanner. Our study showed that the PD-MCI group performed worse on semantic fluency than either the PD-NC or non-PD groups. Increased right angular gyrus activity in participants with PD-MCI during semantic switching suggests early compensatory mechanisms, predicting the risk of future dementia in PD.

Clinical features contributing to the sit-to-stand transfer in people with Parkinson’s disease: a systematic review

Introduction

The aim of this systematic review is to present the existing literature on the clinical motor, and non-motor factors contributing to sit-to-stand transfer in individuals with Parkinson's disease.

Data synthesis

Five databases (PubMed, PEDro, Cochrane, SCOPUS, and Ovid) were searched for literature on the contributing factors to sit-to-stand performance in Parkinson's disease. A quality check of these observational studies was done using the 'strengthening the reporting of observational studies in epidemiology' (STROBE) statement and the tool of the 'National Heart, Lung, and Blood Institute' (NHLBI). Descriptive and quantitative data were extracted and compiled, and a meta-analysis was performed to compute the standardised mean difference.

Results

Thirteen studies were selected; a majority of them provided a high-to-moderate level of evidence. Ten were cross-sectional, while the other three were case–control studies. Collectively, individuals with Parkinson's disease had a prolonged transfer time than those of age-matched healthy peers, particularly from peak horizontal velocity phase to seat-off phase, implying bradykinesia. A reduction in peak and rate to peak joint torques was also related to the decreased pace and stability of the sit-to-stand movement in individuals with Parkinson's disease. Additionally, they demonstrated exaggerated trunk flexion as a postural stabilisation strategy, allowing them to maintain and manoeuvre the relative positions of their centre of mass through the transitional phase of the transfer.

Conclusion

As per the existing literature, an alteration in strength, overall body bradykinesia, balance, posture, as well as cognition may result in an impaired sit-to-stand transfer in individuals with Parkinson's disease.

The Relationship Between Speech Characteristics and Motor Subtypes of Parkinson's Disease

Purpose The aim of this study was to examine whether acoustic dysarthria characteristics align with overall motor profile in individuals with Parkinson's disease (PD). Potential speech differences between tremor-dominant and non-tremor-dominant subtypes are theoretically motivated but empirically inconclusive. Method Twenty-seven individuals with dysarthria from PD provided a contextual speech sample. Participants were grouped into non-tremor-dominant (n = 12) and tremor-dominant (n = 15) motor subtypes according to the Unified Parkinson Disease Rating Scale. Dependent speech variables included fundamental frequency range, average pause duration, cepstral peak prominence, stuttering dysfluencies, and maze dysfluencies. Results There were no significant differences between the speech of the tremor-dominant and non-tremor-dominant groups. High within-group variability existed across parameters and motor subtypes. Conclusion Speech characteristics across the areas of phonation, prosody, and fluency did not differ appreciably between PD motor subtypes.

CCCDTD5 recommendations on early non cognitive markers of dementia: A Canadian consensus

Introduction

Cognitive impairment is the hallmark of Alzheimer's disease (AD) and related dementias. However, motor decline has been recently described as a prodromal state that can help to detect at‐risk individuals. Similarly, sensory changes, sleep and behavior disturbances, and frailty have been associated with higher risk of developing dementia. These clinical findings, together with the recognition that AD pathology precedes the diagnosis by many years, raises the possibility that non‐cognitive changes may be early and non‐invasive markers for AD or, even more provocatively, that treating non‐cognitive aspects may help to prevent or treat AD and related dementias.

Methods

A subcommittee of the Canadian Consensus Conference on Diagnosis and Treatment of Dementia reviewed areas of emerging evidence for non‐cognitive markers of dementia. We examined the literature for five non‐cognitive domains associated with future dementia: motor, sensory (hearing, vision, olfaction), neuro‐behavioral, frailty, and sleep. The Grading of Recommendations Assessment, Development, and Evaluation system was used to assign the strength of the evidence and quality of the recommendations. We provide recommendations to primary care clinics and to specialized memory clinics, answering the following main questions: (1) What are the non‐cognitive and functional changes associated with risk of developing dementia? and (2) What is the evidence that sensory, motor, behavioral, sleep, and frailty markers can serve as potential predictors of dementia?

Results

Evidence supported that gait speed, dual‐task gait speed, grip strength, frailty, neuropsychiatric symptoms, sleep measures, and hearing loss are predictors of dementia. There was insufficient evidence for recommending assessing olfactory and vision impairments as a predictor of dementia.

Conclusions

Non‐cognitive markers can assist in identifying people at risk for cognitive decline or dementia. These non‐cognitive markers may represent prodromal symptoms and several of them are potentially amenable to treatment that might delay the onset of cognitive decline.

EEG Slowing and Axial Motor Impairment Are Independent Predictors of Cognitive Worsening in a Three-Year Cohort of Patients With Parkinson's Disease

Objective: We aimed to determine whether the combination of two parameters: (a) score of axial impairment and limb rigidity (SAILR) with (b) EEG global relative median power in the frequency range theta 4–8 Hz (GRMPT) predicted cognitive outcome in patients with Parkinson's disease (PD) better than each of these measures alone.

Methods: 47 non-demented patients with PD were examined and re-examined after 3 years. At both time-points, the patients underwent a comprehensive neuropsychological and neurological assessment and EEG in eyes-closed resting-state condition. The results of cognitive tests were normalized and individually summarized to obtain a “global cognitive score” (GCS). Change of GCS was used to represent cognitive changes over time. GRMPT and SAILR was used for further analysis. Linear regression models were calculated.

Results: GRMPT and SAILR independently predicted cognitive change. Combination of GRMPT and SAILR improved the significance of the regression model as compared to using each of these measures alone. GRMPT and SAILR only slightly correlate between each other.

Conclusion: The combination of axial signs and rigidity with quantitative EEG improves early identification of patients with PD prone to severe cognitive decline. GRMPT and SAILR seem to reflect different disease mechanisms.

Significance Combination of EEG and axial motor impairment assessment may be a valuable marker in the cognitive prognosis of PD.

Speech difficulties in early de novo patients with Parkinson's disease

INTRODUCTION

Speech difficulties are a common debilitating feature of Parkinson's disease and we aimed to investigate whether speech difficulties are associated with striatal dopaminergic deficits and faster disease progression.

METHODS

Using the Parkinson's Progression Markers Initiative database, 143 early de novo Parkinson's disease patients with speech difficulties were identified and matched 1:1 with 143 Parkinson's disease patients without speech difficulties for age, disease duration and motor symptom severity. We investigated differences in clinical features and striatal [¹²³I]FP-CIT single photon emission computed tomography (SPECT) uptake in Parkinson's disease patients with and without speech difficulties. Cox proportional hazards analysis was carried out to investigate whether speech difficulties were predictive of a faster motor progression and cognitive decline.

RESULTS

Speech difficulties were more common in patients with an akinetic-rigid motor phenotype compared to those with a tremor-dominant phenotype. Parkinson's disease patients with speech difficulties had lower resting tremor (P = 0.027), higher autonomic dysfunction (P = 0.034), increased daytime sleepiness (ESS; P = 0.048), and a higher prevalence of REM sleep behaviour disorder (RBD) symptoms (P = 0.007) compared to those without speech difficulties. Parkinson's disease patients with speech difficulties had significantly lower [¹²³I]FP-CIT uptake in the striatum (P < 0.001), caudate (P = 0.003) and putamen (P = 0.003) compared to those without speech difficulties. The presence of speech difficulties was a predictor of cognitive decline [Hazard Ratio (HR): 0.341, 95% Confidence Interval (CI): 0.153-0.759; Wald: 6.945; P = 0.008), whereas it had no influence on motor progression (HR: 0.885, 95% CI: 0.662-1.183; Wald: 0.680; P > 0.10).

CONCLUSION

Speech difficulties are associated with greater autonomic dysfunction, sleep disturbances and striatal dopaminergic deficit, and can serve as a predictor of faster cognitive decline in early Parkinson's disease.

Altered resting-state functional connectivity of the putamen and internal globus pallidus is related to speech impairment in Parkinson's disease

INTRODUCTION

Speech impairment in Parkinson's disease (PD) is pervasive, with life-impacting consequences. Yet, little is known about how functional connections between the basal ganglia and cortex relate to PD speech impairment (PDSI). Whole-brain resting-state connectivity analyses of basal ganglia nuclei can expand the understanding of PDSI pathophysiology.

METHODS

Resting-state data from 89 right-handed subjects were downloaded from the Parkinson's Progression Markers Initiative database. Subjects included 12 older healthy controls ("OHC"), 42 PD patients without speech impairment ("PDN"), and 35 PD subjects with speech impairment ("PDSI"). Subjects were assigned to PDN and PDSI groups based on the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III speech item scores ("0" vs. "1-4"). Whole-brain functional connectivity was calculated for four basal ganglia seeds in each hemisphere: putamen, caudate, external globus pallidus (GPe), and internal globus pallidus (GPi). For each seed region, group-averaged connectivity maps were compared among OHC, PDN, and PDSI groups using a multivariate ANCOVA controlling for the effects of age and sex. Subsequent planned pairwise t-tests were performed to determine differences between the three groups using a voxel-wise threshold of p < 0.001 and cluster-extent threshold of 272 mm3 (FWE<0.05).

RESULTS

In comparison with OHCs, both PDN and PDSI groups demonstrated significant differences in cortical connectivity with bilateral putamen, bilateral GPe, and right caudate. Compared to the PDN group, the PDSI subjects demonstrated significant differences in cortical connectivity with left putamen and left GPi. PDSI subjects had lower connectivity between the left putamen and left superior temporal gyrus compared to PDN. In addition, PDSI subjects had greater connectivity between left GPi and three cortical regions: left dorsal premotor/laryngeal motor cortex, left angular gyrus, and right angular gyrus.

CONCLUSIONS

The present findings suggest that speech impairment in PD is associated with altered cortical connectivity with left putamen and left GPi.

Relationship Between Posturography, Clinical Balance and Executive Function in Parkinson´s Disease

This study aimed to evaluate the relationship between posturography, clinical balance, and executive function tests in Parkinson´s disease (PD). Seventy-one people participated in the study. Static posturography evaluated the center of pressure fluctuations in quiet standing and dynamic posturography assessed sit-to-stand, tandem walk, and step over an obstacle. Functional balance was evaluated by Berg Balance Scale, MiniBESTest, and Timed Up and Go test. Executive function was assessed by Trail Making Test (TMT) and semantic verbal fluency test. Step over obstacle measures (percentage of body weight transfer and movement time) were moderately correlated to Timed Up and Go, part B of TMT and semantic verbal fluency (r > 0.40; p < 0.05 in all relationships). Stepping over an obstacle assesses the responses to internal perturbations. Participants with shorter movement times and higher percentage of body weight transfer (higher lift up index) on this task were also faster in Timed Up and Go, part B of TMT, and semantic verbal fluency. All these tasks require executive function (problem solving, sequencing, shifting attention), which is affected by PD and contribute to postural assessment.

Postural Instability and Cognitive Dysfunction in Early Parkinson's Disease

Background:

Postural instability is one of the most disabling features of Parkinson's disease, usually occurring in late and advanced stages. The aim of this study was to investigate the postural performance of early-stage de novo Parkinson's disease patients with no clinical postural instability using computerized dynamic posturography. We sought to understand the relationship between postural sway and disease severity and the relationship between postural instability quantitatively measured by computerized dynamic posturography and cognitive impairment in early-stage Parkinson's disease patients.

Method:

Thirty-one subjects with Parkinson's disease and 20 healthy controls were assessed by the computerized dynamic posturography protocol using the sensory organization test and the motor control test. A neuropsychological assessment was also administered.

Results:

The mean equilibrium score for sensory organization test and the vestibular input ratio were significantly correlated with Hoehn-Yahr stage. No associations between motor latency for any motor control test condition and Hoehn-Yahr stage were found. The equilibrium score for sensory organization test correlated with the mini-mental status examination scores. There was a significant correlation between motor latency for large backward translation and mini-mental status examination scores. There were significant correlations between visual perception/construction/ memory of the neuropsychological battery test and the equilibrium score for sensory organization test and between verbal word learning test, controlled word association test and motor latency for large backward translation.

Conclusion:

These findings showed the postural instability present in early-stage (Hoehn-Yahr stage 2-2.5) Parkinson's disease. We also found a close relationship between postural instability and cognitive function in Parkinson's disease patients.

Predictors of cognitive decline in the early stages of Parkinson's disease: a brief cognitive assessment longitudinal study

Our objectives were to perform a longitudinal assessment of mental status in early stage Parkinson's disease (PD) patients, with brief neuropsychological tests, in order to find predictive factors for cognitive decline. Sixty-one, early stage, and nondemented patients were assessed twice, over a 2-year interval, with a global cognitive test (mini-mental state examination (MMSE)) and a frontal function test (frontal assessment battery (FAB)) and motor function scales. Dementia and hallucinations were diagnosed according to the DSM-IV criteria. Cognitive function scores did not decrease significantly, except for FAB lexical fluency score. Four patients presented with dementia at followup. The MMSE score below cut-off, worse gait dysfunction, the nontremor motor subtype, and hallucinations were significantly related to dementia. Rigidity and speech dysfunction were related to dementia and a decrease in FAB scores. We can conclude that decline in the MMSE and FAB scores is small and heterogeneous in the early stages of PD. Scores below cut-off in the MMSE could be helpful to predict dementia. Nontremor motor deficits could be predictive factors for frontal cognitive decline and dementia.