442 research outputs found
Measuring through questionnaires : Rasch analysis as a tool for keeping the same meaning across different patients
No full textWhole-person variables may describe behaviours, perceptions, knowledges, attitudes. These are the outcomes of the most various health-care interventions. Such variables can only be observed through samples of representatives behaviours (items in questionnaires). The amount of the variables is usually inferred through counts of the scores arbitrarily assigned to the various items. Rasch Analysis (RA) is a novel statistical method allowing the estimate of true linear measures of item difficulty and subject ability subtended by raw counts. This also allows the estimate of stability of the items hierarchy (which item is more difficult, which is less) across time, raters and diagnostic or cultural subgroups. If this hierarchy is unstable (Differential Item Functioning – DIF) the same questionnaire actually depicts qualitatively distinct, non comparable, conditions. RA may help to either detect the problem, or re-calibrate the subject measures by accounting for DIF. This may warrant real metric equivalence across medical questionnaires applied to different diagnostic groups and/or different linguistic/cultural contests, thus fostering multicentric, international trials
Concentrations of L-dopa in plasma and plasma ultrafiltrates.
No full textA sensitive and specific procedure is described for the determination of therapeutically relevant concentrations of L-dopa in plasma and plasma ultrafiltrates (free fraction) by high performance liquid chromatography with electrochemical detection. In plasma samples from healthy adult subjects (n = 15) spiked with L-dopa (500 μg l -1) the free fraction averaged 76 ± 8% (range 61-84%). Free fraction values increased by 38% with increasing plasma concentrations of L-dopa from 100-5000 μg l -1. L-dopa free fraction was not affected by the presence of 3-o-methyl-dopa a concentrations up to 10 000 μg l
A model for fatigue generation and exercise prescription in multiple sclerosis patients
No full textPersons with multiple sclerosis often suffer from fatigue primarily reflecting the burden of disease. The most direct manifestation is an increased sense of effort for even light activities. This can be thought of as the result of "inefficiency" in the neural programme that translates the motor intention into the proper pattern of muscle contractions. A model is proposed, based on the mismatch between the actual movement and the "efference copy" of the motor programme. Examples of exercises consistent with this model are provided
Exercise in neurological rehabilitation : from empyrism to evidence-based research
No full textA 40-year-old man underwent surgery for a right middle ear cholesteatoma. One month later, he presented with a subacute ocular pain that was followed one day later by the appearance of vertical diplopia attributable to a right superior rectus paresis, lid ptosis and hypoaesthesia in the territory of the I and the II right trigeminal branches. A fatsuppressed (selective partial inversion recovery, SPIR) gadolinium-enhanced MRI favours the detection of inflammatory pathological tissue inside the right cavernous sinus, and in this patient it suggested a diagnosis of Tolosa-Hunt syndrome. The pain disappeared quickly after steroid treatment was started whereas the ocular nerve involvement improved only slightly during the first week of treatment. After two months, the patient only complained of diplopia on up-gaze, but the therapy was discontinued two months later on the basis of both clinical signs and MRI findings. SPIR MRI may be useful not only to support a diagnosis of Tolosa-Hunt syndrome, but also to follow-up the disease course and to manage steroid treatment
The 3-D trajectory of the body center of mass during walking : normative parameters from adult human walking on instrumented treadmill
No full textThe 3D trajectory of the body centre of mass during adult human walking: Evidence for a speed–curvature power law
No full textDuring straightwalking, the body centre of mass (CM) follows a 3D figure-of-eight (‘‘bow-tie’’) trajectory
about 0.2 m long and with sizes around 0.05 m on each orthogonal axis. This was shown in 18 healthy
adults walking at 0.3 to 1.4 m s1 on a force-treadmill (Tesio and Rota, 2008). Double integration of force
signals can provide both the changes of mechanical energy of the CM and its 3D displacements (Tesio
et al., 2010). In the same subjects, the relationship between the tangential speed of the CM, Vt, the
curvature, C, and its inverse—the radius of curvature, rc, were analyzed. A ‘‘power law’’ (PL) model was
applied, i.e. log Vt was regressed over log rc. A PL is known to apply to the most various goal-directed
planar movements (e.g. drawing), where the coefficient of log rc, b, usually takes values around 13
. When
the PL was fitted to the whole dataset, b was 0.346 and variance explanation, R2, was 59.8%. However,
when the data were split into low- and high-curvature subsets (LC, HC, arbitrary cut-off of C1⁄40.05 mm1,
rc1⁄420 mm), b was 0.185 in the LC (R2 0.214) and 0.486 in the HC (R2 0.536) tracts. R2 on the whole dataset
increased to 0.763 if the LC–HC classification of the forward speed and their interaction entered the
model. The b coefficient, the curvature C, and the pendulum-like recovery of mechanical energy were
lower during the double foot-ground contact phase, compared to the single contact. Along the CM
trajectory, curvature and muscle power output peaked together around the inversions of lateral direction.
Non-zero torsion values were randomly distributed along 60% of the trajectory, suggesting that this is not
segmented into piecewise planar tracts. It is proposed that the trajectory can be segmented into one tract
that is more actively controlled (tie) where a PL fits poorly and another tract which ismore ballistic (bow)
where a PL fits well. Results need confirmation through more appropriate 3D PL modelling
Author Response: Does Screening for Adverse Effects Improve Health Outcomes in Epilepsy? A Randomized Trial
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