Lateralisation in Parkinson disease.

Asymmetry of dopaminergic neurodegeneration and subsequent lateralisation of motor symptoms are distinctive features of Parkinson's disease compared to other forms of neurodegenerative or symptomatic parkinsonism. Even 200 years after the first description of the disease, the underlying causes for this striking clinicopathological feature are not yet fully understood. There is increasing evidence that lateralisation of disease is due to a complex interplay of hereditary and environmental factors that are reflected not only in the concept of dominant hemispheres and handedness but also in specific susceptibilities of neuronal subpopulations within the substantia nigra. As a consequence, not only the obvious lateralisation of motor symptoms occurs but also patterns of associated non-motor signs are defined, which include cognitive functions, sleep behaviour or olfaction. Better understanding of the mechanisms contributing to lateralisation of neurodegeneration and the resulting patterns of clinical phenotypes based on bilateral post-mortem brain analyses and clinical studies focusing on right/left hemispheric symptom origin will help to develop more targeted therapeutic approaches, taking into account subtypes of PD as a heterogeneous disorder.

Trekking poles increase physiological responses to hiking without increased perceived exertion.

Trekking poles are used by hikers for improved stability and lowered leg fatigue due to increased upper body muscle involvement. However, the weight of the poles and exaggerated upper body movement when using poles may increase total energy expenditure at a given walking speed. Few studies have investigated the physiological responses of hiking with trekking poles outside the laboratory setting. The purposes of this study were to determine if trekking poles altered physiological responses to hiking on varied terrain, and whether responses between trials were dependent on the grade of the terrain. Fourteen recreational hikers completed four hiking trials over a course that included sustained sections of flat (0 +/- 1% grade), steep uphill (>10% grade), gradual uphill (5% grade), gradual downhill (-5% grade) and steep downhill (<-10% grade) terrain. Subjects walked at a self-selected speed that was matched across trials using time-splits and a metronome. Two trials were conducted with hiking poles and two without poles. [latin capital V with dot above]O2 was significantly elevated (p <0.05) during the pole trials (1502.9 +/- 510.7 ml/min) compared to the no-pole trials (1362.4 +/- 473.2 ml/min). Similarly, ventilatory efficiency ([latin capital V with dot above]E) (43.1 +/- 9.6; 38.3 +/- 10.1 L/min) and heart rate (HR) (112.1 +/- 9.7; 105.7 +/- 10.4 bt/min) were significantly higher during the pole trials than the no-pole trials. However, ratings of perceived exertion (RPE) was not altered by pole condition (8.5 +/- 0.7; 8.4 +/- 0.8). Comparisons within each grade revealed significantly higher physiological responses for [latin capital V with dot above]O2, [latin capital V with dot above]E and HR in the pole-condition at all grades, with no significant variable*grade interactions. RPE measures were not significantly different between pole trials at any grade. These data suggest that trekking poles may be a beneficial tool for increasing caloric expenditure, as energy production increased during exercise without increased perceptions of effort.