PROSPERO; CRD42017057450.

The results suggest that improved gait dynamics do not necessarily represent improved walking stability, and this must be respected when rehabilitating gait in patients with PD.

Background The use of alternate frequencies, amplitudes, and pulse widths to manage motor symptoms in Parkinson's disease (PD) patients with subthalamic nucleus deep brain stimulation (STN‐DBS) is of clinical interest, but currently lacks systematic evidence. Objective/Hypothesis Systematically review whether alternate STN‐DBS settings influence the therapy's efficacy for managing PD motor symptoms. Methods Systematic searches identified studies that; involved bilateral STN‐DBS PD patients; manipulated ≥ 1 STN‐DBS parameter (e.g., amplitude); assessed ≥ 1 motor symptom (e.g., tremor); and contrasted the experimental and chronic stimulation settings. A Mantel‐Haenszel random‐effects meta‐analysis compared the UPDRS‐III sub‐scores at low (60‐Hz) and high frequencies ( ≥ 130 Hz). Inter‐study heterogeneity was assessed with the Cohen's χ2 and I2 index, while the standard GRADE evidence assessment examined strength of evidence. Results Of the 21 included studies, 17 investigated the effect of alternate stimulation frequencies, five examined alternate stimulation amplitudes, and two studied changes in pulse width. Given the available data, meta‐analyses were only possible for alternate stimulation frequencies. Analysis of the heterogeneity amongst the included studies indicated significant variability between studies and, on the basis of the GRADE framework, the pooled evidence from the meta‐analysis studies was of very low quality due to the significant risks of bias. Conclusions The meta‐analysis reported a very low quality of evidence for the efficacy of low‐frequency STN‐DBS for managing PD motor symptoms. Furthermore, it highlighted that lower amplitudes lead to the re‐emergence of motor symptoms and further research is needed to understand the potential benefits of alternate STN‐DBS parameters for PD patients.

It is well understood that stability during ambulation is reliant upon appropriate control of the trunk segment, but research shows that the rhythmicity of this segment is significantly reduced for people with Parkinson's disease (PD). Given the increased risk associated with stair ambulation, this study investigated whether people with PD demonstrate poorer trunk control during stair ambulation compared with age-matched controls. Trunk accelerations were recorded for twelve PD patients and age-matched controls during stair ascent and descent. Accelerations were used to derive measures of harmonic ratios and root mean square (RMS) acceleration to provide insight into the rhythmicity and amplitude of segmental motion. Compared with what is typically seen during level-ground walking, gait rhythmicity during stair negotiation was markedly reduced for older adults and people with PD. Furthermore, both groups exhibited significantly poorer trunk movements during stair descent compared to stair ascent, suggesting that both populations may face a greater risk of falling during this task. As stair negotiation is a common activity of daily life, the increased risk associated with this task should be considered when working with populations that have an increased risk of falling.

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