Prospective controlled study on the effects of deep brain stimulation on driving in Parkinson's disease

To explore the influence of bilateral subthalamic deep brain stimulation (STN-DBS) on car driving ability in patients with Parkinson's disease (PD), we prospectively examined two age-matched, actively driving PD patient groups: one group undergone DBS-surgery (PD-DBS, n = 23) and one group that was eligible for DBS but did not undergo surgery (PD-nDBS, n = 29). In PD-DBS patients, investigation at Baseline was done just prior and at Follow-up 6-12 month after DBS-surgery. In PD-nDBS patients, time interval between Baseline and Follow-up was aimed to be comparable. To assess the general PD driving level, driving was assessed once in 33 age-matched healthy controls at Baseline. As results, clinical and driving characteristics of PD-DBS, PD-nDBS and controls did not differ at Baseline. At Follow-up, PD-DBS patients drove unsafer than PD-nDBS patients. This effect was strongly driven by two single PD-DBS participants (9%) with poor Baseline and disastrous Follow-up driving performance. Retrospectively, we could not identify any of the assessed motor and non-motor clinical Baseline characteristics as predictive for this driving-deterioration at Follow-up. Excluding these two outliers, comparable driving performance between PD-DBS and PD-nDBS patients not only at Baseline but also at Follow-up was demonstrated. Age, disease duration and severity as well as Baseline driving insecurity were associated with poorer driving performance at Follow-up. This first prospective study on driving safety in PD after DBS surgery indicates that DBS usually does not alter driving safety but might increase the risk for driving deterioration, especially in single subjects with already unsafe driving prior to DBS surgery.

Analyses of Gait Parameters of Younger and Older Adults During (Non-)Isometric Virtual Walking

Understanding real walking in virtual environments (VEs) is important for immersive experiences, allowing users to move through VEs in the most natural way. Previous studies have shown that basic implementations of real walking in virtual spaces, in which head-tracked movements are mapped isometrically to a VE, are not estimated as entirely natural. Instead, users estimate a virtual walking velocity as more natural when it is slightly increased compared to the user's physical locomotion. However, these findings have been reported in most cases only for young persons, e.g., students, whereas older adults are clearly underrepresented in such studies. Recently, virtual reality (VR) has received significant public and media attention. Therefore, it appears reasonable to assume that people at different ages will have access to VR, and might use this technology more and more in application scenarios such as rehabilitation or training. To better understand how people at different ages walk and perceive locomotion in VR, we have performed a study to investigate the effects of (non-)isometric mappings between physical movements and virtual motions in the VE on the walking biomechanics across generations, i.e., younger and older adults. Three primary domains (pace, base of support and phase) of spatio-temporal parameters were identified to evaluate gait performance. The results show that the older adults walked very similar in the real and VE in the pace and phasic domains, which differs from results found in younger adults. In contrast, the results indicate differences in terms of base of support domain parameters for both groups while walking within a VE and the real world. For non-isometric mappings, we found in both younger and older adults an increased divergence of gait parameters in all domains correlating with the up- or down-scaled velocity of visual self-motion feedback. The results provide important insights into the design of future VR applications for older adults in domains ranging from medicine and psychology to rehabilitation.

Adverse events in deep brain stimulation: A retrospective long-term analysis of neurological, psychiatric and other occurrences

Background and objective

The extent to which deep brain stimulation (DBS) can improve quality of life may be perceived as a permanent trade-off between neurological improvements and complications of therapy, comorbidities, and disease progression.

Patients and methods

We retrospectively investigated 123 consecutive and non-preselected patients. Indications for DBS surgery were Parkinson's disease (82), dystonia (18), tremor of different etiology (21), Huntington's disease (1) and Gilles de la Tourette syndrome (1). AEs were defined as any untoward clinical occurrence, sign or patient complaint or unintended disease if related or unrelated to the surgical procedures, implanted devices or ongoing DBS therapy.

Results

Over a mean/median follow-up period of 4.7 years (578 patient-years) 433 AEs were recorded in 106 of 123 patients (86.2%). There was no mortality or persistent morbidity from the surgical procedure. All serious adverse events (SAEs) that occurred within 4 weeks of surgery were reversible. Neurological AEs (193 in 85 patients) and psychiatric AEs (78 in 48 patients) were documented most frequently. AEs in 4 patients (suicide under GPI stimulation, weight gain >20 kg, impairment of gait and speech, cognitive decline >2 years following surgery) were severe or worse, at least possibly related to DBS and non reversible. In PD 23.1% of the STN-stimulated patients experienced non-reversible (or unknown reversibility) AEs that were at least possibly related to DBS in the form of impaired speech or gait, depression, weight gain, cognitive disturbances or urinary incontinence (severity was mild or moderate in 15 of 18 patients). Age and Hoehn&Yahr stage of STN-simulated PD patients, but not preoperative motor impairment or response to levodopa, showed a weak correlation (r = 0.24 and 0.22, respectively) with the number of AEs.

Conclusions

DBS-related AEs that were severe or worse and non-reversible were only observed in PD (4 of 82 patients; 4.9%), but not in other diseases. PD patients exhibited a significant risk for non-severe AEs most of which also represented preexisting and progressive axial and non-motor symptoms of PD. Mild gait and/or speech disturbances were rather frequent complaints under VIM stimulation. GPI stimulation for dystonia could be applied with negligible DBS-related side effects.