Diagnostic value of the rapid assessment of postural instability in Parkinson's disease (RAPID) questionnaire

Niacin Enhancement for Parkinson's Disease: An Effectiveness Trial

We previously reported that individuals with Parkinson’s disease (PD) present with lower vitamin B3 levels compared to controls. It may be related to carbidopa interaction, defective tryptophan metabolism, and stresses of night sleep disorder. Vitamin B3 is the energy source for all cells by producing NAD⁺ and NADP⁺ in redox reactions of oxidative phosphorylation. Thus, some symptoms of PD such as fatigue, sleep dysfunction, and mood changes may be related to the deficiency of vitamin B3. Here, we conducted an effectiveness trial to determine the effect of 12 months of low-dose niacin (a vitamin B3 derivative) enhancement in PD individuals. An average of 9 ± 6-point improvement in the Unified Parkinson’s Disease Rating Scale (UPDRS) III (motor) score was observed after 12 months of daily niacin compared to the expected decline in score (effect size = 0.78, 95% CI = 7–11). Additionally, secondary outcome measures improved. Notably, handwriting size increased, fatigue perception decreased, mood improved, frontal beta rhythm during quiet stance increased, and stance postural sway amplitude and range of acceleration decreased. Set shifting, however, as measured by the Trail Making-B test, worsened from 66 to 96 s. Other measures did not change after 12 months, but it is not clear whether this represents a positive benefit of the vitamin. For example, while the quality of night sleep remained the same, there was a trend towards a decrease in the frequency of awakening episodes. These results suggest that niacin enhancement has the potential to maintain or improve quality of life in PD and slow disease progression.

Measures of balance and falls risk prediction in people with Parkinson's disease: a systematic review of psychometric properties

OBJECTIVE

To investigate the psychometric properties of measures of balance and falls risk prediction in people with Parkinson's disease (PD).

DATA SOURCES

PubMed, Embase, CINAHL, Ovid Medline, Scopus, and Web of Science were searched from inception to August 2019.

REVIEW METHOD

Studies testing psychometric properties of measures of balance and falls risk prediction in PD were included. The four-point COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) assessed quality.

RESULTS

Eighty studies testing 68 outcome measures were reviewed; 43 measures assessed balance, 9 assessed falls risk prediction, and 16 assessed both. The measures with robust psychometric estimation with acceptable properties were the (1) Mini-Balance Evaluation Systems Test (Mini-BEST), (2) Berg Balance Scale, (3) Timed Up and Go test, (4) Falls Efficacy Scale International, and (5) Activities-Specific Balance Confidence scale. These measures assess balance and falls risk prediction at the body, structure and function level, falls risk and balance, and falls risk at the activity level. The motor examination of the Unified Parkinson's Disease Rating Scale (UPDRS-ME) with robust psychometric analysis is a condition-specific measure with acceptable properties. Except the UPDRS-ME and Mini-BESTest, the responsiveness of the other four measures has yet to be established.

CONCLUSION

Six of the 68 outcome measures have strong psychometric properties for the assessment of balance and falls risk prediction in PD. Measures assessing balance and falls risk prediction at the participatory level are limited in number with a lack of psychometric validation.

Duration of step initiation predicts freezing in Parkinson's disease

OBJECTIVES

In some individuals with idiopathic Parkinson's disease (PD), freezing of gait episodes develops as the disease progresses. The neural mechanism underlying freezing in PD is poorly understood. Here, we report a 2-year follow-up on the novel discovery of prolonged step initiation duration as a potential marker of impending freezing.

METHODS

Non-freezing PD participants in stages 2.5-4 of the Hoehn and Yahr disease severity scale were recruited from an earlier study which determined the effect of semi-virtual cues on walking. Responders were those who completed the first step faster in the presence of the virtual cues while non-responders either did not change or took longer to complete the first step. Both groups of participants were interviewed 2 years later to determine who had developed freezing of gait.

RESULTS

Participants in the responder group had a 13-fold risk of developing freezing of gait within 2 years following the cueing study (OR=13.3, 95% CI=1.1-167). A cutoff score of -2.6% (i.e., a decrease in the duration of the first step with visual cues by 2.6% relative to no cues) gave a sensitivity and specificity of 100% and 89%, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first novel discovery of a physical predictor of freezing in PD. The time to complete the first step is a simple test to administer in the clinic or at home and may therefore be easily incorporated into a fall prevention training program for PD before the inception of freezing.

Upregulation of GPR109A in Parkinson's disease

BACKGROUND

Anecdotal animal and human studies have implicated the symptomatic and neuroprotective roles of niacin in Parkinson's disease (PD). Niacin has a high affinity for GPR109A, an anti-inflammatory receptor. Niacin is also thought to be involved in the regulation of circadian rhythm. Here we evaluated the relationships among the receptor, niacin levels and EEG night-sleep in individuals with PD.

METHODS AND FINDINGS

GPR109A expression (blood and brain), niacin index (NAD-NADP ratio) and cytokine markers (blood) were analyzed. Measures of night-sleep function (EEG) and perceived sleep quality (questionnaire) were assessed. We observed significant up-regulation of GPR109A expression in the blood as well as in the substantia nigra (SN) in the PD group compared to age-matched controls. Confocal microscopy demonstrated co-localization of GPR109A staining with microglia in PD SN. Pro and anti-inflammatory cytokines did not show significant differences between the groups; however IL1-β, IL-4 and IL-7 showed an upward trend in PD. Time to sleep (sleep latency), EEG REM and sleep efficiency were different between PD and age-matched controls. Niacin levels were lower in PD and were associated with increased frequency of experiencing body pain and decreased duration of deep sleep.

CONCLUSIONS

The findings of associations among the GPR109A receptor, niacin levels and night-sleep function in individuals with PD are novel. Further studies are needed to understand the pathophysiological mechanisms of action of niacin, GPR109A expression and their associations with night-sleep function. It would be also crucial to study GPR109A expression in neurons, astrocytes, and microglia in PD. A clinical trial to determine the symptomatic and/or neuroprotective effect of niacin supplementation is warranted.

Clinical and posturographic correlates of falling in Parkinson's disease

Various clinical tests and balance scales have been used to assess postural stability and the risk of falling in patients with idiopathic Parkinson's disease (IPD). Quantitative posturography allows a more objective assessment but the findings in previous studies have been inconsistent and few studies have investigated which posturographic measures correlate best with a history of falling. The purpose of this study was to determine the efficacy of clinical tests, balance scales, and stable-platform posturography in detecting postural instability and discriminating between fallers and non-fallers in a home-dwelling PD cohort. Forty-eight PD subjects (Hoehn & Yahr stage 1-3) and 17 age-matched controls had the following assessments: Activities-specific Balance Confidence scale, Berg Balance Scale, Unified Parkinson's Disease Rating Scale (UPDRS) (motor), pull-test, timed up-and-go, static posturography, and dynamic posturography to assess multidirectional leaning balance. Of the clinical assessments, all but the pull-test were closely correlated with a history of falling. Static posturography discriminated between PD fallers and controls but not between PD fallers and non-fallers, whereas dynamic posturography (reaction time, velocity, and target hit-time) also discriminated between fallers and non-fallers. Our findings suggest that this combination of clinical and posturographic measures would be useful in the prospective assessment of falls risk in PD patients. A further prospective study is now required to assess their predictive value. © 2013 Movement Disorder Society.