[Deep brain stimulation and gait disorders in Parkinson disease]

A Topographic Atlas of the Human Brainstem in the Ponto-Mesencephalic Junction Plane

The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal information that travels between the cerebral cortex, the cerebellum and the spinal cord. As such, this relatively small portion of the human brain houses a multitude of ascending and descending fibers that course among numerous nuclei whose exact boundaries are still uncertain. Such a large number of nuclei and fiber tracts confined to a relatively small and compact brain region imposes upon the brainstem a highly complex cytoarchitectonic organization that still needs to be deciphered. The present work provides a topographic atlas of the human brainstem composed of 45 anatomical plates, each containing a pair of adjacent sections stained with Cresyl Violet and Luxol Fast Blue to help delineating brainstem nuclei and fiber tracts, respectively. The plates, which cover the entire midbrain, pons and medulla oblongata, are composed of equally-spaced sections referenced and aligned parallel to the ponto-mesencephalic junction rather than the fastigium or the obex. This topographic landmark is particularly suitable for neurosurgical interventions aiming at specific nuclei of the mesencephalic tegmentum. In complement, we provide 8 anatomical plates containing adjacent sections stained for choline acetyltransferase and Luxol Fast Blue, taken through the midbrain and the pons. This open access atlas of the human brainstem is intended to assist neuroanatomists, neurosurgeons and neuropathologists in their work.

Effectiveness of robot-assisted gait training on freezing of gait in people with Parkinson disease: evidence from a literature review

The aim of this review was to evaluate, summarize and discuss the available literature concerning the effect of robot-assisted gait training (RAGT) on patient with Parkinson disease (PD) and freezing of gait (FOG). A comprehensive literature search was conducted utilizing of MEDLINE, Embase, Scopus, Web of Science, PEDro (Physiotherapy Evidence Database), and the Cochrane Review. Search terms used in-cluded 'Parkinson disease,' 'Freezing of gait,' 'RAGT,' 'robot-assisted gait training,' 'Locomotor rehabilitation,' 'gait trainer,' and 'robotics assisted gait training.' A total of 4 studies were evaluated, but these studies were primarily of low-level evidence. All the 4 studies noted positive outcomes with using RAGT on FOG. No adverse events or side effects that occurred during and/or after the interventions. While the current literature generally offers support for the use of RAGT for FOG treatment, there is a paucity of strong evidence to support its widespread use. The increasing availability of RAGT technology offers the potential for engaging therapy in FOG rehabilitation, but its utility remains uncertain given the limited studies available at this time.

Pedunculopontine nucleus area oscillations during stance, stepping and freezing in Parkinson's disease

The pedunculopontine area (PPNa) including the pedunculopontine and cuneiform nuclei, belongs to the mesencephalic locomotor region. Little is known about the oscillatory mechanisms underlying the function of this region in postural and gait control. We examined the modulations of the oscillatory activity of the PPNa and cortex during stepping, a surrogate of gait, and stance in seven Parkinson’s disease patients who received bilateral PPNa implantation for disabling freezing of gait (FOG). In the days following the surgery, we recorded behavioural data together with the local field potentials of the PPNa during sitting, standing and stepping-in-place, under two dopaminergic medication conditions (OFF and ON levodopa). Our results showed that OFF levodopa, all subjects had FOG during step-in-place trials, while ON levodopa, stepping was effective (mean duration of FOG decreasing from 61.7±36.1% to 7.3±10.1% of trial duration). ON levodopa, there was an increase in PPNa alpha (5–12 Hz) oscillatory activity and a decrease in beta (13–35 Hz) and gamma (65–90 Hz) bands activity. PPNa activity was not modulated during quiet standing and sitting. Our results confirm the role of the PPNa in the regulation of gait and suggest that, in Parkinson disease, gait difficulties could be related to an imbalance between low and higher frequencies.