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Background Cranioplasty is an increasingly common procedure performed in neurosurgical centres following a decompressive craniectomy (DC), however, timing of the procedure varies greatly. Objectives The aim of this study is to compare the surgical outcomes of an early compared to a late cranioplasty procedure. Methods Ninety adult patients who underwent a prosthetic cranioplasty between 2014 and 2017 were studied retrospectively. Timing of operation, perioperative complications and length of stay were assessed. Early and late cranioplasties were defined as less or more than 3 months since craniectomy respectively. Results Of the 90 patients, 73% received a late cranioplasty and 27% received an early cranioplasty. The median interval between craniectomy and cranioplasty was 13 months [range 3–84] in late group versus 54 days [range 33–90] in early group. Twenty-two patients in the early group (91%) received a cranioplasty during the original admission while undergoing rehabilitation. Complications were seen in 25 patients (28%). These included wound or cranioplasty infection, hydrocephalus, symptomatic pneumocephalus, post-operative haematoma and cosmetic issues. The complication rate was 21% in the early group and 30% in the late group (P value 0.46). There was no significant difference in the rate of infection or hydrocephalus between the two groups. Length of stay was not significantly increased in patients who received an early cranioplasty during their initial admission (median length of stay 77 days versus 63 days, P value 0.28). Conclusion We have demonstrated the potential for early cranioplasty to be a safe and viable option, when compared to delayed cranioplasty.

Extracting event-related potentials (ERPs) from neurological rhythms is of fundamental importance in neuroscience research. Standard ERP techniques typically require the associated ERP waveform to have low variance, be shape and latency invariant and require many repeated trials. Additionally, the non-ERP part of the signal needs to be sampled from an uncorrelated Gaussian process. This limits methods of analysis to quantifying simple behaviours and movements only when multi-trial data-sets are available. We introduce a method for automatically detecting events associated with complex or large-scale behaviours, where the ERP need not conform to the aforementioned requirements. The algorithm is based on the calculation of a detection contour and adaptive threshold. These are combined using logical operations to produce a binary signal indicating the presence (or absence) of an event with the associated detection parameters tuned using a multi-objective genetic algorithm. To validate the proposed methodology, deep brain signals were recorded from implanted electrodes in patients with Parkinson's disease as they participated in a large movement-based behavioural paradigm. The experiment involved bilateral recordings of local field potentials from the sub-thalamic nucleus (STN) and pedunculopontine nucleus (PPN) during an orientation task. After tuning, the algorithm is able to extract events achieving training set sensitivities and specificities of [87.5 ± 6.5, 76.7 ± 12.8, 90.0 ± 4.1] and [92.6 ± 6.3, 86.0 ± 9.0, 29.8 ± 12.3] (mean ± 1 std) for the three subjects, averaged across the four neural sites. Furthermore, the methodology has the potential for utility in real-time applications as only a single-trial ERP is required.

The objectives of this study were (1) to characterize protective stepping responses to unpredictable forward/backward postural perturbation in Parkinson's disease (PD) and (2) to assess whether vibrotactile cues of the impending fall improve the stepping response. Twenty mild PD patients, 7 advanced PD patients, and 17 age-matched controls stood on a platform moving unpredictably forward and backward, requiring a protective step to maintain balance. Direction-coded vibrotactile cues, triggered by leg tilt, were provided to prompt step generation. All subjects showed quicker reaction time, shorter steps, and smaller total trunk displacement when stepping backward than when stepping forward. Advanced PD patients took shorter, slower, and an increased number of protective steps. The only abnormality observed in mild PD patients was slightly slower backward steps. Vibrotactile feedback reduced the amount of trunk displacement observed before taking a protective step but did not improve any abnormality in PD patients. Early PD patients had near-normal protective stepping responses to unpredictable perturbations, but advanced patients made slow and short steps both forward and backward. Given that latencies were preserved even in unpredictable conditions, step slowness and hypometria are the primary abnormalities of the stepping response in PD. As voluntary locomotor stepping in PD is reported to improve with sensory feedback, the lack of such improvement in our study implies that additional sensory cues cannot help automatic reflex-like stepping reactions in PD patients.

The quadripolar electrodes used for deep brain stimulation are designed to give flexibility in contact configuration, optimize therapeutic effect, and minimize side-effects. A patient with essential tremor did not tolerate a bipolar setting due to the emergence of a pulling sensation in her face. However, when the polarity of the contacts was reversed, a 70% higher voltage was tolerated. Using an electric field model, we predicted that this effect was due to the proximity of the topmost contact to the internal capsule. Post-operative imaging supported this prediction. These results demonstrate how a multi-disciplinary approach allows us to optimize parameter settings.

The objectives of this study were (1) to characterize protective stepping responses to unpredictable forward/backward postural perturbation in Parkinson's disease (PD) and (2) to assess whether vibrotactile cues of the impending fall improve the stepping response. Twenty mild PD patients, 7 advanced PD patients, and 17 age-matched controls stood on a platform moving unpredictably forward and backward, requiring a protective step to maintain balance. Direction-coded vibrotactile cues, triggered by leg tilt, were provided to prompt step generation. All subjects showed quicker reaction time, shorter steps, and smaller total trunk displacement when stepping backward than when stepping forward. Advanced PD patients took shorter, slower, and an increased number of protective steps. The only abnormality observed in mild PD patients was slightly slower backward steps. Vibrotactile feedback reduced the amount of trunk displacement observed before taking a protective step but did not improve any abnormality in PD patients. Early PD patients had near-normal protective stepping responses to unpredictable perturbations, but advanced patients made slow and short steps both forward and backward. Given that latencies were preserved even in unpredictable conditions, step slowness and hypometria are the primary abnormalities of the stepping response in PD. As voluntary locomotor stepping in PD is reported to improve with sensory feedback, the lack of such improvement in our study implies that additional sensory cues cannot help automatic reflex-like stepping reactions in PD patients.