Development and evaluation of RAMP I – a practitioner’s tool for screening of musculoskeletal disorder risk factors in manual handling

<p>RAMP I is a screening tool developed to support practitioners in screening for work-related musculoskeletal disorder risk factors related to manual handling. RAMP I, which is part of the RAMP tool, is based on research-based studies combined with expert group judgments. More than 80 practitioners participated in the development of RAMP I. The tool consists of dichotomous assessment items grouped into seven categories. Acceptable reliability was found for a majority of the assessment items for 15 practitioners who were given 1 h of training. The usability evaluation points to RAMP I being usable for screening for musculoskeletal disorder risk factors, i.e., usable for assessing risks, being usable as a decision base, having clear results and that the time needed for an assessment is acceptable. It is concluded that RAMP I is a usable tool for practitioners.</p

Neck/shoulder discomfort due to visually demanding experimental near work is influenced by previous neck pain, task duration, astigmatism, internal eye discomfort and accommodation

<div><p>Visually demanding near work can cause eye discomfort, and eye and neck/shoulder discomfort during, e.g., computer work are associated. To investigate direct effects of experimental near work on eye and neck/shoulder discomfort, 33 individuals with chronic neck pain and 33 healthy control subjects performed a visual task four times using four different trial lenses (referred to as four different viewing conditions), and they rated eye and neck/shoulder discomfort at baseline and after each task. Since symptoms of eye discomfort may differ depending on the underlying cause, two categories were used; <i>internal eye discomfort</i>, such as ache and strain, that may be caused by accommodative or vergence stress; and <i>external eye discomfort</i>, such as burning and smarting, that may be caused by dry-eye disorders. The cumulative performance time (reflected in the temporal order of the tasks), astigmatism, accommodation response and concurrent symptoms of internal eye discomfort all aggravated neck/shoulder discomfort, but there was no significant effect of external eye discomfort. There was also an interaction effect between the temporal order and internal eye discomfort: participants with a greater mean increase in internal eye discomfort also developed more neck/shoulder discomfort with time. Since moderate musculoskeletal symptoms are a risk factor for more severe symptoms, it is important to ensure a good visual environment in occupations involving visually demanding near work.</p></div

Interaction effect from GEE model 3.

<p>The interaction effect of the temporal order of the viewing conditions and the difference in the ratings of internal eye discomfort from baseline to the various viewing conditions on the mean predicted rating of neck/shoulder discomfort (GEE model 3). To illustrate the difference between small and large differences in internal eye discomfort the participants were divided into the 25^th percentile (dotted line, mean difference -0.04, n = 17), and the 75^th percentile (solid line, mean difference4.33, n = 17) using the variable ΔIntEye.</p

Descriptive statistics.

<p>The refractive errors of our participants, accommodation responses (D) and heart rate variability during the various viewing conditions, and the mean difference in trapezius muscle activity between rest and the various viewing conditions. The difference between the groups were analysed with Mann-Whitney U test. Unless otherwise indicated, the values presented are means with standard deviation in brackets (n = number of participants for whom reliable information was available).</p

Borg’s CR-10 scale along with the written descriptors.

<p>Borg’s CR-10 scale along with the written descriptors.</p

The laboratory set-up.

<p>This is a schematic illustration of the experimental set-up in the laboratory. The distance to the Far target was 3 m (0.33 D) for all subjects. The distance to the near target was individually adjusted to be 5 D away from each individual’s near point of accommodation (NAD + 5 D). D = diopters.</p

Estimated parameters by the GEE.

<p>Estimates of the parameters by the GEE including significant variables (model 2) and including interaction effects between temporal order and internal eye discomfort (model 3).</p

Eye and neck/shoulder discomfort.

<p>The ratings of internal and external eye discomfort and and neck/shoulder discomfort by the control and neck groups at baseline following the four viewing conditions presented as the temporal order of the rating (1, 2, 3 and 4), and as the rating after a specific viewing condition (MN, BM, MM, MP). The values presented are medians with the range in brackets.</p

Cross-correlation functions.

<p>Mean cross-correlation curves and the 95% confidence intervals (grey lines). The curves to the left shows the control group (n = 14), and the curves to the right shows the patient group (n = 12). a—b) neutral viewing condition, c—d) negative viewing condition, e—f) positive viewing condition.</p

Results from the cross-correlation analyses.

<p>Cross-correlation analyses were run within groups (controls and patients) and viewing conditions. One sample t-test tested if maximal cross-correlation (R(time shift)) differed from zero (p-value in brackets). Viewing conditions: neutral = no lenses, negative = -3.5 D lenses, positive = 3.5 D lenses. CI = 95% confidence intervals.</p><p>* Time shift not possible to estimate due to the shape of the curve (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126578#pone.0126578.g006" target="_blank">Fig 6d</a>).</p><p>Results from the cross-correlation analyses.</p