Influence of Alcohol Intake on the Parameters Evaluating the Body Center of Foot Pressure in a Static Upright Posture

Centre of pressure changes during stance but not during gait in young women after alcohol intoxication

Background

Women are underrepresented in research focused on alcohol (e.g., Brighton, Moxham & Traynor, 2016; DOI 10.1097/JAN.0000000000000136) despite the changing patterns of alcohol consumption, which has been increasing in women in recent decades. The purpose of this study was to analyse the relationship between habitual alcohol consumption and centre of pressure (CoP) parameters during stance and gait while intoxicated by alcohol.

Methods

Thirty women (24.39 ± 2.93 years) participated in this study. All participants were asked to answer the AUDIT questionnaire. Stance and gait analysis were repeated under two conditions on a Zebris platform (FDM GmbH; Munich, Germany): when the participants were sober (0.00% breath alcohol concentration, BrAC) and when they were in an intoxicated state (0.11% BrAC). Participants were divided by their AUDIT score into a low-risk alcohol consumption group (n = 15; AUDIT score: 3 to 6) and a hazardous alcohol consumption group (n = 15; AUDIT score: 7 to 13).

Results

No statistical difference was observed in stance and gait parameters when comparing the low-risk and hazardous groups under 0.00% BrAC and 0.11% BrAC conditions. A statistically significant difference was observed when comparing 0.00% BrAC and 0.11% BrAC conditions within each group. This significant difference was found in CoP path length and CoP average velocity during quiet stance. However, no statistically significant differences were observed in CoP parameters during gait. An alcohol intoxication of 0.11% BrAC was not sufficient to cause statistically significant impairments in butterfly parameters of gait.

The laser-pointer assisted angle reproduction test for evaluation of proprioceptive shoulder function in patients with instability

INTRODUCTION

Over the last decade, proprioceptive function gained increasing attention in joint disorders such as instability of the shoulder. Common tests for evaluation of proprioception are limited by their complexity and high technical demands. Thus, they are hardly applicable during daily routine. Our hypothesis was that the simplified "laser-pointer assisted angle reproduction test" (LP-ART) presented here allows for clinically feasible assessment of proprioceptive shoulder function.

METHODS

Active angle reproduction capability as an aspect of sensorimotor function was evaluated with the new method in patients with shoulder instability (n = 24) and healthy controls (n = 24). 15 patients had traumatic, 9 non-traumatic anterior instability (6 bilateral), 17 were treated surgically, 13 non-operatively. Tests were performed in flexion and abduction in different angles (55°, 90°, 125°) in randomized order.

RESULTS

Angle reproduction capability was worst below shoulder level (55°) in all groups. Best results were achieved at shoulder level (90°). Healthy controls showed overall better results than patients with instability. Patients after surgical stabilization had better results in 55° and 90° abduction compared to instability patients before surgery.

CONCLUSIONS

The new LP-ART presented here is a technically simple, yet effective instrument for evaluation of the proprioceptive function of the shoulder. In contrast to former test setups it is feasible in daily routine. Compared to healthy controls, patients with unstable shoulder joints show significant proprioceptive disorders that can be quantified by the LP-ART.

Measuring oscillating walking paths with a LIDAR

This work describes the analysis of different walking paths registered using a Light Detection And Ranging (LIDAR) laser range sensor in order to measure oscillating trajectories during unsupervised walking. The estimate of the gait and trajectory parameters were obtained with a terrestrial LIDAR placed 100 mm above the ground with the scanning plane parallel to the floor to measure the trajectory of the legs without attaching any markers or modifying the floor. Three different large walking experiments were performed to test the proposed measurement system with straight and oscillating trajectories. The main advantages of the proposed system are the possibility to measure several steps and obtain average gait parameters and the minimum infrastructure required. This measurement system enables the development of new ambulatory applications based on the analysis of the gait and the trajectory during a walk.

Examining Differences between Center of Pressure Sway in One-Legged and Two-Legged Stances for Soccer Players and Typical Adults

To examine stance during the measurement of balance ability, this study aimed to clarify the differences and relationships between balance ability in one-legged (dominant or nondominant leg) and two-legged stances in 25 typical male adults and 25 male soccer players. Balance ability was evaluated with four sway factors: sway velocity, anterior-posterior sway, lateral sway, and high-frequency sway factors. The one-legged stance was more unstable than the two-legged stance, the balance abilities related to two-legged and one-legged stances differed, and the balance abilities related to dominant-legged and nondominant-legged stances were similar. The one-legged stance, which was difficult to maintain stably, may be useful in the measurement of static balance ability in young people.

Human and laboratory rodent low response to alcohol: is better consilience possible?

If people are brought into the laboratory and given alcohol, there are pronounced differences among individuals in many responses to the drug. Some participants in alcohol challenge protocols show a cluster of 'low level of responses to alcohol' determined by observing post-drinking-related changes in subjective, motor and physiological effects at a given dose level. Those individuals characterized as having low level of response (LR) to alcohol have been shown to be at increased risk for a lifetime diagnosis of alcohol dependence (AD), and this relationship between low LR and AD appears to be in part genetic. LR to alcohol is an area where achieving greater consilience between the human and the rodent phenotypes would seem to be highly likely. However, despite extensive data from both human and rodent studies, few attempts have been made to evaluate the human and animal data systematically in order to understand which aspects of LR appear to be most directly comparable across species and thus the most promising for further study. We review four general aspects of LR that could be compared between humans and laboratory animals: (1) behavioral measures of subjective intoxication; (2) body sway; (3) endocrine responses; and (4) stimulant, autonomic and electrophysiological responses. None of these aspects of LR provide completely face-valid direct comparisons across species. Nevertheless, one of the most replicated findings in humans is the low subjective response, but, as it may reflect either aversively valenced and/or positively valenced responses to alcohol as usually assessed, it is unclear which rodent responses are analogous. Stimulated heart rate appears to be consistent in animal and human studies, although at-risk subjects appear to be more rather than less sensitive to alcohol using this measure. The hormone and electrophysiological data offer strong possibilities of understanding the neurobiological mechanisms, but the rodent data in particular are rather sparse and unsystematic. Therefore, we suggest that more effort is still needed to collect data using refined measures designed to be more directly comparable in humans and animals. Additionally, the genetically mediated mechanisms underlying this endophenotype need to be characterized further across species.

Low-Alcohol Doses Reduce Common 10- to 15-Hz Input to Bilateral Leg Muscles During Quiet Standing

The effects of low doses of alcohol on neural synchronization in muscular activity were investigated in ten participants during quiet standing with eyes open or closed. We focused on changes in common input to bilateral motor unit pools as evident in surface electromyographic (EMG) recordings of lower leg extensor and flexor muscles. The extensor muscles exhibited bilateral synchronization in two distinct frequency bands (i.e., 0–5 and 10–15 Hz), whereas synchronization between flexor muscles was minimal. As expected, alcohol ingestion affected postural sway, yielding increased sway at higher blood-alcohol levels. Whereas vision affected bilateral synchronization only at 0–5 Hz, alcohol ingestion resulted in a progressive decrease of synchronization at 10–15 Hz between the EMG activities of the extensor muscles. The decrease in common bilateral input is most likely related to reduced reticulospinal activity with alcohol ingestion.