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Background: Cueing strategies can alleviate freezing of gait (FOG) in people with Parkinson's disease (PD). We evaluated tactile cueing delivered via vibrating socks, which has the benefit of not being noticeable to bystanders., Objective: To evaluate the effect of tactile cueing compared to auditory cueing on FOG., Methods: Thirty-one persons with PD with FOG performed gait tasks during both ON and OFF state. The effect of open loop and closed loop tactile cueing, as delivered by vibrating socks, was compared to an active control group (auditory cueing) and to a baseline condition (uncued gait). These four conditions were balanced between subjects. Gait tasks were videotaped and annotated for FOG by two experienced raters. Motion data were collected to analyze spatiotemporal gait parameters. Responders were defined as manifesting a relative reduction of > 10% in the percent time frozen compared to uncued gait., Results: The average percent time frozen during uncued gait was 11.2% in ON and 21.5% in OFF state. None of the three tested cueing modalities affected the percentage of time frozen in either the ON (p = 0.20) or OFF state (p = 0.12). The number of FOG episodes and spatiotemporal gait parameters were also not affected. We found that 22 out of 31 subjects responded to cueing, the response to the three types of cueing was highly individual., Conclusions: Cueing did not improve FOG at the group level; however, tactile as well as auditory cueing improved FOG in many individuals. This highlights the need for a personalized approach when using cueing to treat FOG., (© 2023. The Author(s).)

Introduction: Outcome-based payment models (OBPMs) might solve the shortcomings of fee-for-service or diagnostic-related group (DRG) models using financial incentives based on outcome indicators of the provided care. This review provides an analysis of the characteristics and effectiveness of OBPMs, to determine which models lead to favourable effects., Methods: We first developed a definition for OBPMs. Next, we searched four data sources to identify the models: (1) scientific literature databases; (2) websites of relevant governmental and scientific agencies; (3) the reference lists of included articles; (4) experts in the field. We only selected studies that examined the impact of the payment model on quality and/or costs. A narrative evidence synthesis was used to link specific design features to effects on quality of care or healthcare costs., Results: We included 88 articles, describing 12 OBPMs. We identified two groups of models based on differences in design features: narrow OBPMs (financial incentives based on quality indicators) and broad OBPMs (combination of global budgets, risk sharing, and financial incentives based on quality indicators). Most (5 out of 9) of the narrow OBPMs showed positive effects on quality; the others had mixed (2) or negative (2) effects. The effects of narrow OBPMs on healthcare utilization or costs, however, were unfavourable (3) or unknown (6). All broad OBPMs (3) showed positive effects on quality of care, while reducing healthcare cost growth., Discussion: Although strong empirical evidence on the effects of OBPMs on healthcare quality, utilization, and costs is limited, our findings suggest that broad OBPMs may be preferred over narrow OBPMs.

Various ancillary investigations can assist clinicians in the differential diagnosis of patients with parkinsonism. It is unknown which test offers greatest diagnostic value in clinical practice. We included 156 consecutive patients with parkinsonism, but with an initially uncertain diagnosis. At baseline, all patients underwent extensive clinical testing and the following ancillary investigations: brain magnetic resonance imaging (MRI); (123)I-iodobenzamide single photon-emission computed tomography (IBZM-SPECT); analysis of cerebrospinal fluid (CSF); and anal sphincter electromyography (EMG). The final diagnosis was established after 3-year follow-up by two movement disorder specialists, according to international consensus criteria. We determined the diagnostic value by comparing the baseline clinical parameters and ancillary studies with the final diagnosis. Out of a potential 138 parameters, univariate analysis identified 35 parameters that discriminated Parkinson's disease (PD, n = 62) and atypical parkinsonism (AP, n = 94), with AUC of 0.55-0.81. Stepwise logistic regression showed that the combination of tandem gait, axial UPDRS subscore, slow saccadic eye movements and dysphagia yielded an AUC of 0.93, adjusted for optimism. The combination of tandem gait and axial UDPRS subscore yielded an AUC of 0.90. None of the ancillary investigations alone or in combination with clinical testing improved this clinically based diagnostic accuracy, not even in a subgroup of patients with the greatest diagnostic uncertainty at baseline. Our study demonstrates that a comprehensive set of clinical tests provides good accuracy to differentiate PD from AP. Our results also suggest that routine MRI, IBZM-SPECT, CSF analysis and anal sphincter EMG do not improve this diagnostic accuracy. Future work should evaluate the possible diagnostic value of more advanced diagnostic tests.

Imaging and neuropathology studies have demonstrated significant abnormalities not only in subcortical, but also in cortical regions of patients with multiple system atrophy (MSA). This raises the possibility that cognitive dysfunction may contribute to the clinical spectrum of this disorder to a greater extent than it is currently not widely appreciated. In this cross-sectional multicenter study from the European multiple system atrophy study group ( http://www.emsa-sg.org ), we applied an extensive neuropsychological test battery in a series of 61 clinically diagnosed probable MSA patients. The results demonstrated that general cognitive decline as assessed by MMSE was uncommon (2 out of 61 patients <24). In contrast, frontal lobe-related functions (as measured by FAB) were impaired in 41 % of patients, with abstract reasoning and sustained attention less compromised. This pattern was similar to our control group of 20 patients with Parkinson's disease (matched for disease duration and age at onset). There was no difference in cognitive performance between MSA patients with the parkinsonian versus the cerebellar variant. Behaviourally, MSA patients had greater depression than PD and in the case of MSA of the cerebellar variant significantly lower anxiety. Our data show that cognitive abnormalities are relatively frequent in multiple system atrophy and this involves primarily frontal-executive functions. Their contribution to clinical disability and disease progression needs to be addressed in larger prospective studies.

Drooling (saliva loss) is a frequently reported symptom in patients with Parkinson's disease (PD), but an accurate estimate of the prevalence of drooling is lacking. The aim of this study was to systematically review the prevalence of drooling in published research papers. A systematic PubMed and CINAHL search was done, including studies published until January 2009. Eight studies were found, presenting prevalence rates of drooling based on responses of PD patients to questionnaires. The statistical heterogeneity was highly significant (P < 0.0001), with prevalence rates ranging from 32 to 74%. The pooled prevalence estimate with random effect analysis was of 56% (95% CI 44-67) for PD patients and 14% (95% CI 3-25) for healthy controls; the pooled relative risk (RR) with random effect analysis was 5.5 (95% CI 2.1-14.4). All studies reported data of community dwelling idiopathic PD patients, with a mean age around 65 years and mild PD in 50-60% of the cases. Heterogeneity was mainly caused by differences in definition or frequency of drooling. The highest prevalence rates included nocturnal drooling where others noted only diurnal drooling. Analysis of the data of two studies showed that drooling is reported frequently by 22-26% of the patients. Prevalence rates were lower in milder PD patients. The summarized findings demonstrate that drooling can be present in half of all PD patients. In about a quarter of PD patients, drooling appears to be a frequently occurring problem. We recommend to report drooling in future studies with more detailed consideration of severity, frequency and nocturnal versus diurnal complaints.

Unintended weight loss frequently complicates the course of many neurodegenerative disorders and can contribute substantially to both morbidity and mortality. This will be illustrated here by reviewing the characteristics of unintended weight loss in the three major neurodegenerative disorders: Alzheimer's disease, Parkinson's disease and Huntington's disease. A common denominator of weight loss in these neurodegenerative disorders is its typically complex pathophysiology. Timely recognition of the underlying pathophysiological process is of crucial importance, since a tailored treatment of weight loss can considerably improve the quality of life. This treatment is, primarily, comprised of a number of methods of increasing energy intake. Moreover, there are indications for defects in the systemic energy homeostasis and gastrointestinal function, which may also serve as therapeutic targets. However, the clinical merits of such interventions have yet to be demonstrated.

Freezing of gait (FOG) in Parkinson's disease (PD) is defined as a sudden inability to maintain effective stepping movements. However, its pathophysiology remains unclear. The objectives are: (1) To assess the contribution of both spatial (walking speed, stride length) and temporal parameters (cadence, stride time) and their coefficients of variation to the genesis of FOG in PD. (2) To evaluate whether and how externally imposed modifications of self-determined gait would elicit FOG. We included ten patients with advanced PD, and with daily off drug FOG episodes. We focused on walking in an open runway. For each subject, we manipulated gait by externally imposing four changes in walking speed and four changes in cadence. FOG episodes, often with a long duration of more than 5-s, were observed mostly under conditions with a high imposed cadence. The steps that immediately preceded these episodes were mainly characterized by an increase in cadence and an increase in stride length variability. The results also underscore that FOG can be elicited in a laboratory setting when patients are placed under considerable strain, at least in advanced stages of PD. Patients were unable to adequately negotiate the extreme imposed cadence condition, and this resulted in frequent FOG episodes, even while walking in an open runway. Placing advanced PD patients into extreme imposed conditions leads to a motor wise and mental collapse response, culminating in FOG. Future work should establish the relevance of these findings for the more common forms of FOG, including brief episodes during turning or gait initiation.

Background: To determine the diagnostic value of the clapping test, which has been proposed as a reliable measure to differentiate between progressive supranuclear palsy (where performance is impaired) and Parkinson's disease (where performance should be normal)., Methods: Our study group included a large cohort of consecutive outpatients including 44 patients with Parkinson's disease, 48 patients with various forms of atypical parkinsonism and 149 control subjects. All subjects performed the clapping test according to a standardized protocol., Results: Clapping test performance was normal in all control subjects, and impaired in 63% of the patients with atypical parkinsonism. Unexpectedly, we also found an impaired clapping test in 29% of the patients with Parkinson's disease., Conclusion: Although the proportion with an abnormal clapping test was significantly higher in atypical parkinsonism, the clapping test did not discriminate well between Parkinson's disease and atypical parkinsonism.

We aimed to quantify the effects of bilateral subthalamic nucleus (STN) stimulation in Parkinson's disease (PD) on stance and gait ("axial"motor control), and related this to effects on finger movements ("appendicular" motor control). Fourteen PD patients and 20 matched controls participated. Subjects completed several balance and gait tasks (standing with eyes open or closed, on a normal or foam surface; retropulsion test; walking with eyes closed; walking up and down stairs; Get Up and Go test). Postural control was quantified using trunk sway measurements (angle and angular velocity) in the roll and pitch directions. Subjects further performed a pinch grip reaction time task, where we measured isometric grip forces, as well as movement and reaction times. Patients were examined with STN stimulators switched on or off (order randomised across patients), always after a supramaximal levodopa dosage. STN stimulation improved postural control, as reflected by a reduced trunk sway tremor during stance, a reduced duration for all gait tasks, an increased trunk pitch velocity while rising from a chair, and improved roll stability. STN stimulation also improved finger control, as reflected by a reduced time to reach maximum grip force, without altering reaction times and maximum force levels. Improvements in finger control timing did not correlate with reduced task durations during gait. We conclude that STN stimulation affords improvement of postural control in PD, over and above optimal drug treatment. STN stimulation also provides a simultaneous effect on distal and axial motor control. Because improvements in distal and axial motor control were not correlated, we assume that these effects are mediated by stimulation of different structures within the STN.

We studied prospectively the epidemiology, clinical impact and prediction of falls in 59 moderately affected patients with Parkinson's disease (PD) (mean UPDRS motor score 31.5; mean age 61 years) and 55 controls (mean age 60 years). At baseline, balance and gait were evaluated extensively. The retropulsion test (response to sudden shoulder pull) was executed first unexpectedly and five more times following prior warning. All persons used standardised scoring forms to document their falls during six months. Thirty patients (50.8 %) and eight controls (14.5%) fell at least once (relative risk [RR] 6.1; 95% confidence interval [CI] 2.5-15.1, p < 0.001). Recurrent (> or = 2) falls occurred in 15 patients (25.4%), but in only two controls (RR 9.0; 95 % CI 2.0-41.7; p=0.001). Recurrent falls were more common among persons taking benzodiazepines (RR 5.0; 95% CI 1.6-15.5; p < 0.01). Sixty-two percent of the falls in patients caused soft tissue injuries, but no fractures occurred. A fear of future falls was common (45.8 % of patients) and was accompanied by restriction of daily activities (44.1 % of patients). Seventy percent of falls reported by patients were'intrinsic' (due to patient-related factors), but falls in controls were mainly (50%) 'extrinsic' (due to environmental factors). None of the baseline posture and gait variables predicted falls adequately. The first 'unexpected' retropulsion test was more often abnormal than all subsequent (predictable) tests. Irrespective of its method of execution, the retropulsion test did not predict falls. A combination of asking for prior falls, disease severity and the Romberg test yielded the best overall diagnostic utility (sensitivity 65 % and specificity 98 %). Recurrent fallers were best predicted by disease severity (RR for Hoehn and Yahr stage 3 was > 100; 95% CI 3.1-585) and asking for prior falls (RR 5.0; 95% CI 1.2-20.9). We conclude that falls are common and disabling, even in relatively early stage PD. Recurrent fallers were best predicted by disease severity and presence of prior falls. Strategies to prevent falls in PD should particularly focus at intrinsic (patient-related) factors, such as minimising the use of benzodiazepines.

Bilateral deep brain stimulation is an effective treatment for most motor signs of Parkinson's disease (PD), but the effects on cognitive functions are less clear. We therefore examined the effects of bilateral deep brain stimulation on central information processing, using the event-related auditory P300 potential as an electrophysiological index of mental chronometry. Eight PD patients with bilateral stimulators within the subthalamic nuclei (STN) and eight age-matched controls participated. Patients were examined after overnight withdrawal of antiparkinson medication, both "on" and "off" stimulation (in random sequence). The P300 and reaction times were recorded using an auditory oddball paradigm. P300 latencies were prolonged in PD patients off stimulation (440 +/- 45 ms) compared to controls (397 +/- 16 ms; P < 0.05). STN stimulation significantly reduced clinical disease severity (as indexed by the Unified Parkinson's Disease Rating Scale) and markedly improved reaction times, but did not improve the prolonged P300 latencies in PD patients (429 +/- 36 ms). These results confirm that P300 latencies are prolonged in PD. Significantly, bilateral STN stimulation did not improve this electrophysiological measure of cognitive impairment, even though motor disability was markedly reduced. This suggests that some dopa-responsive features are resistant to STN stimulation, possibly due to involvement of dopaminergic deficits outside the nigrostriatal pathway, which are not influenced by outflow from the STN.