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Outcome studies in biomedical research usually focus on testing mean changes across samples of subjects and, in so doing, often obscure changes in individuals. These changes, however, may be very informative in studies in which large or homogeneous samples are unavailable and mechanisms of action are still under scrutiny, as is often the case for trials on new exercise treatments. Single measurements of change may be valid, provided that the reliability of the measurement process (i.e. instrument and procedure combined) was ascertained in a dedicated study in which appropriate statistical models and algorithms were applied. This article summarizes the conceptual steps that allow the calculation of the minimal real difference (MRD, also known as the minimal detectable change), on the basis of the assessment of reliability using an intraclass correlation coefficient. Individuals who show changes beyond the MRD can be reliably considered as changed. A numerical example of an MRD calculation is shown, and the pros and cons of the mean change and the MRD approach are discussed.

Variables present in an individual, for example, independence, pain, balance, fatigue, depression and knowledge, cannot be measured directly (hence the term "latent" variables). They are usually assessed by measuring related behaviours, defined by sets of standardized items. The homogeneity of the different items, and proportionality of raw counts to measure, can only be postulated. In 1960 Georg Rasch proposed a statistical model that complied with the fundamental assumptions made in measurements in physical sciences. It allowed for the transformation of the cumulative raw scores (achieved by a subject across items, or by an item across subjects) into linear continuous measures of ability (for subjects) and difficulty (for items). These 2 parameters, only, govern the probability that "pass" rather than "fail" occurs. The discrepancies between model-expected scores (continuous between 0 and 1) and observed scores (discrete, either 0 or 1) provide indexes of inconsistency of individual subjects, items and classes of subjects. In subsequent years the same principles were extended to rating scales, with items graded on more than 2 levels, and to "many-facet" contexts where, beyond items and subjects, multiple raters, times of administration, etc. converge in determining the observed scores. Rasch modelling has increasing application in rehabilitation medicine. New scales with unprecedented metric validity (including internal consistency and reliability) can be built. Existing scales can be improved or rejected on a sound theoretical basis. In clinical trials the consistency and the linearity of measures of either subjects or raters can be validly matched with those of physical and chemical measures. The stability of the item difficulties across time, cultures, diagnostic groups and time of administration can be estimated, thus making it possible to compare homogeneous measures or foster diagnostic procedures on the reasons for differential item functioning.

The study sought to provide norms for a simple test of visual perception of verticality (subjective visual vertical). The study was designed as a cohort study with a balanced design. The setting was the Rehabilitation Department of a University Hospital. Twenty-two healthy adults, of 23-58 years, 11 men (three left handed) and 11 women (three left handed) were enrolled. A luminous bar was displayed on a PC screen, and rotated in steps of 0.4 degrees until the participant perceived it as vertical. A positive sign was attributed to a clockwise rotation of the bar. The detection threshold was set at the angle corresponding to a perceived vertical, which the participant then selected out of three subsequent alternatives (each at +0.4 or -0.4 degrees). The participant's position (sitting vs. standing) and the preset angle of presentation (clockwise vs. counterclockwise) were balanced across sex. The constant or deviation error (dE, in degrees) and the absolute errors (aE, in degrees) were computed. An analysis of variance model tested the dependence of dE on sex, posture, age, handedness, and the preset angle. Both dE and aE were unrelated to sex, posture, handedness, and the preset angle, but were dependent on age (junior, less than or equal to 43 years; senior, greater than 43 years). The mean dE was -0.14 plus or minus 0.60 in the junior and 0.42 plus or minus 0.64 in the senior group, respectively. The minimal real difference of the dE was 0.75 and 0.25 in the junior and the senior group, respectively. The overall median aE was 0.4 (5th-95th percentile 0-1.2) in the junior and 0.8 (0.4-1.46) in the senior group, respectively. The whole test took no longer than 15 min in healthy participants, and 25 min in stroke patients. The test was applied to three subacute stroke patients with left hemiparesis, of whom two showed left spatial hemineglect. All three patients presented with a significant clockwise dE. This simple test appears to be valid for the routine assessment of spatial disorders in neurological impairments.

ABILHAND is, in its original version, a 46-item, 4-level questionnaire. It measures the difficulty perceived by patients with rheumatoid arthritis as they do various daily manual tasks. ABILHAND was originally built through Rasch analysis. In a later study, it was simplified to a generic 23-item, three-level questionnaire, showing both cross-cultural (Belgium vs. Italy) and cross-impairment (rheumatoid arthritis vs. stroke) validity. Later research returned to the development of impairment-specific versions, with modified item sets and levels. Each version has its own Rasch-derived item difficulty calibrations, which are required to extract the patient's measure from the individual string of responses, through computerized algorithms. All of these hamper the practical application of the scale in rehabilitation units, where patients with diverse conditions may share similar impairments and treatment approaches. In this study through Rasch analysis the "generic" scale was applied to 126 chronic patients with different upper limb impairments, and to 24 healthy controls. It was supported that the generic questionnaire remains valid across a variety of motor impairments. To further facilitate clinical application, a normative cut-off ([greater than]79 of 100) is suggested. Rasch-based item calibrations are provided together with a software routine designed to calculate, on individual patients, linear 0-100 measures and error estimates from the raw scores.

Any person is provided by characteristics that can be neither located in body parts nor directly observed (so-called latent variables): these may be behaviors, attitudes, perceptions, motor and cognitive skills, knowledge, emotions, and the like. Physical and rehabilitation medicine frequently faces variables of this kind, the target of many interventions. Latent variables can only be observed through representative behaviors (e.g., walking for independence, moaning for pain, social isolation for depression, etc.). To measure them, behaviors are often listed and summated as items in cumulative questionnaires ("scales"). Questionnaires ultimately provide observations ("raw scores") with the aspect of numbers. Unfortunately, they are only a rough and often misleading approximation to true measures for various reasons. Measures should satisfy the same measurement axioms of physical sciences. In the article, the flaws hidden in questionnaires' scores are summarized, and their consequences in outcome assessment are highlighted. The report should inspire a critical attitude in the readers and foster the interest in modern item response theory, with reference to Rasch analysis. [ABSTRACT FROM AUTHOR]

Measurements of person's variable, such as behavior, perceptions, or attitudes, are essential to physical and rehabilitation medicine in both clinical practice and research. These measurements are commonly based on cumulative questionnaires and follow special statistical rules, belonging to the domain of psychometrics. Selecting the most appropriate measurement is critical. This article provides an overview of the standard psychometric criteria to consider in measurement selection. The article focuses on the criteria related to the contemporary psychometric approach as it considers the construct, the target population, and the purpose for which measurements are used. Common strategies related to psychometric testing are discussed and applied to critically appraise, as a representative example, one of the most commonly used pain measurements: Brief Pain Inventory. The measurement construct, conceptual framework, target population, purpose, and psychometric properties are highlighted. Observed limitations for its implementation in different settings also are discussed. [ABSTRACT FROM AUTHOR]

Although rare, central post-stroke pain remains one of the most refractory forms of neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) has been reported to be effective in chronic cases. However, there are no data on the effects in the acute and subacute phases after stroke. In this study, we present a case of a patient with thalamic stroke with acute onset of pain and paresthesia who was responsive to rTMS. After a right thalamic stroke, a 32-year-old woman presented with drug-resistant pain and paresthesia on the left side of the body. There were no motor or sensory deficits, except for blunted thermal sensation and allodynia on light touch. Ten daily sessions were performed, where 10 Hz rTMS was applied to the hand area of the right primary motor cortex, 40 days after stroke. Before rTMS treatment (T0), immediately after treatment conclusion (T1), and 1 month after treatment (T2), three pain questionnaires were administered, and cortical responses to single and paired-pulse TMS were assessed. Eight healthy participants served as controls. At T0, when the patient was experiencing the worst pain, the excitability of the ipsilesional motor cortex was reduced. At T1 and T2, the pain scores and paresthesia' spread decreased. The clinical improvement was paralleled by the recovery in motor cortex excitability of the affected hemisphere, in terms of both intra- and inter-hemispheric connections. In this subacute central post-stroke pain case, rTMS treatment was associated with decreased pain and motor cortex excitability changes. [ABSTRACT FROM AUTHOR]

Unilateral spatial neglect (USN) is a neuropsychological syndrome, typically caused by lesions of the right hemisphere, whose features are the defective report of events occurring in the left (contralesional) side of space and the inability to orient and set up actions leftwards. Multisensory integration mechanisms, largely spared in USN patients, may temporally modulate spatial orienting. In this pilot study, the effects of an intensive audio-visual Multisensory Stimulation (MS) on USN were assessed, and compared with those of a treatment that ameliorates USN, Prismatic Adaptation (PA). Twenty USN stroke patients received a 2-week treatment (20 sessions, twice per day) of MS or PA. The effects of MS and PA were assessed by a set of neuropsychological clinical tests (target cancellation, line bisection, sentence reading, personal neglect, complex drawing) and the Catherine Bergego Scale for functional disability. Results showed that MS brought about an amelioration of USN deficits overall comparable to that induced by PA; personal neglect was improved only by MS, not by PA. The clinical gains of the MS treatment were not influenced by duration of disease and lesion volume, and they persisted up to one month post-treatment. In conclusion, MS represents a novel and promising rehabilitation procedure for USN. [ABSTRACT FROM AUTHOR]

BACKGROUND: A method of measurement of voluntary activation (VA, percent of full muscle recruitment) during isometric and isokinetic concentric contractions of the quadriceps femoris (QF) at 60 ∘ /s and 120 ∘ /s was previously validated. OBJECTIVE: This study aimed to quantify the test-retest minimal real difference (MRD) of VA during isometric (ISOM) and isokinetic concentric contractions of QF (100 ∘ /s, ISOK) in a sample of healthy individuals. METHODS: VA was measured through the interpolated twitch technique. Pairs of electrical stimuli were delivered to the QF at 40 ∘ of knee flexion during maximal voluntary contractions. Twenty-five healthy participants (20–38 years, 12 women, 13 men) completed two testing sessions with a 14-day interval. VA values were linearized through logit transformation (VA l). The MRD was estimated from intraclass correlation coefficients (model 2.1). RESULTS: The VA (median, range) was 84.20% (38.2–99.9%) in ISOM and 94.22% (33.8–100%) in ISOK. MRD was 0.78 and 1.12 logit for ISOM and ISOK, respectively. As an example, in terms of percent VA these values correspond to a change from 76% to 95% and from 79% to 98% in ISOM and in ISOK, respectively. CONCLUSIONS: The provided MRD values allow to detect significant individual changes in VA, as expected after training and rehabilitation programs. [ABSTRACT FROM AUTHOR]

Walking on split-belt treadmills (each belt rotating at a different velocity) has inspired a growing number of researchers to study gait adaptation and rehabilitation. An overlooked peculiarity of this artificial form of gait is that the mean velocity adopted by the participant, considered as a whole system represented by the body Center of Mass, can be different from the mean velocity of the two belts. Twelve healthy adults (21–34 yrs) were requested to walk for 15 mins on a treadmill with belts rotating at 0.4 and 1.2 m sec−1, respectively (mean = 0.8 m sec−1). Each belt was supported by four 3-dimensional force sensors. For each participant, six strides were analyzed during the 1st and the 15th minute of the trial. The mean Center of Mass velocity was computed as the sum of the velocities of each belt weighted by the percentage of time during which the resulting forces, underlying the accelerations of the Center of Mass, originated from each belt. Across early and late observations, the median Center of Mass velocities were 0.72 and 0.67 m sec−1, respectively (P < 0.05). Therefore, the real velocity of the Center of Mass and its time course should be individually assessed when studying walking on split-belt treadmills. [ABSTRACT FROM AUTHOR]

The article presents a study on the effectiveness of ground walking and electrical lumbar epidural stimulation as treatments for chronic complete spinal cord injury. Other topics include the causal inferences between biological interventions and behavioral outcomes in injury treatment, and the spinal central pattern generator (CPG) model.

Fibromyalgia (FM) is a frequent, complex condition of chronic musculoskeletal pain with no evidence for biological correlates. For this reason, despite many efforts from the medical community, its construct still appears ill defined. Promising candidate biomarkers are critically reviewed. A research agenda is proposed for developing a clearer construct of FM. The ideal theoretical framework is one of overcoming the illness–disease dichotomy and considering reciprocal interactions between biology and behaviour. This approach may foster research in other fields of pain medicine and of medicine in general. [ABSTRACT FROM AUTHOR]

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To examine the fourth version of the Spinal Cord Independence Measure for reliability and validity. Partly blinded comparison with the criterion standard Spinal Cord Independence Measure III, and between examiners and examinations. A multicultural cohort from 19 spinal cord injury units in 11 countries. A total of 648 patients with spinal cord injury. Assessment with Spinal Cord Independence Measure (SCIM IV) and Spinal Cord Independence Measure (SCIM III) on admission to inpatient rehabilitation and before discharge. SCIM IV interrater reliability, internal consistency, correlation with and difference from SCIM III, and responsiveness. Total agreement between examiners was above 80% on most SCIM IV tasks. All Kappa coefficients were above 0.70 and statistically significant (P <.001). Pearson's coefficients of the correlation between the examiners were above 0.90, and intraclass correlation coefficients were above 0.90. Cronbach's alpha was above 0.96 for the entire SCIM IV, above 0.66 for the subscales, and usually decreased when an item was eliminated. Reliability values were lower for the subscale of respiration and sphincter management, and on admission than at discharge. SCIM IV and SCIM III mean values were very close, and the coefficients of Pearson correlation between them were 0.91-0.96 (P <.001). The responsiveness of SCIM IV was not significantly different from that of SCIM III in most of the comparisons. The validity, reliability, and responsiveness of SCIM IV, which was adjusted to assess specific patient conditions or situations that SCIM III does not address, and which includes more accurate definitions of certain scoring criteria, are very good and quite similar to those of SCIM III. SCIM IV can be used for clinical and research trials, including international multi-center studies, and its group scores can be compared with those of SCIM III. [ABSTRACT FROM AUTHOR]

The author discusses the proposed program of international rotation in integrative rehabilitation medicine implemented as part of the physical medicine and rehabilitation residency program (PMR). He states that the scientific basis of complementary and alternative medicine (CAM) is yet to be ascertained. He discusses the confusion between CAM and PMR regarding the definition of alternative medicines. He states that its exposure may compromise the foundations of conventional medicines.

Objective: To evaluate the psychometric properties of Mini-Mental State Examination (MMSE) in patients with acquired brain injury in Turkey. Methods: A total of 207 patients with acquired brain injury were assessed. Reliability was tested by internal consistency and the person separation index; internal construct validity by Rasch analysis; external construct validity by correlation with cognitive disability; and cross-cultural validity by differential item functioning analysis compared with Italian MMSE data. Results: Reliability was adequate with a Cronbach's alpha of 0.75 and person separation index of 0.76. After collapsing some categories, and adjustment for differential item functioning, internal construct validity was supported by fit of the data to Rasch model. Differential item functioning for culture was found in 2 items and after adjustment, data could be pooled between Turkey and Italy. External construct validity was supported by expected associations. Conclusion: The Turkish version of the Mini-Mental State Examination can be used as a cognitive screening tool in acquired brain injury. Cross-cultural validity between Italy and Turkey is supported, given appropriate adjustment for differential item functioning. However, shortfalls in reliability at the individual level, as well as the presence of differential item functioning suggest that a better instrument should be developed to screen for cognitive deficits following acquired brain injury. [ABSTRACT FROM AUTHOR]

Objective: To analyse cross-cultural validity of the Functional Independence Measure (FIM™) in patients with stroke using the Rasch model. Settings: Thirty-one rehabilitation facilities within 6 different countries in Europe. Participants: A total of 2546 in-patients at admission, median age 63 years. Methods: Data from the FIM™ were evaluated with the Rasch model, using the Rasch analysis package RUMM2020. A detailed analysis of scoring functions of the 7 categories of the FIM items was undertaken prior to testing fit to the model. Categories were re-scored where necessary. Analysis of Differential Item Functioning was undertaken in pooled data for each of the FIM motor and social-cognitive scales, respectively. Results: Disordered thresholds were found on most items when using 7 categories. Fit to the Rasch model varied between countries. Differential Item Functioning was found by country for most items. Adequate fit to the Rasch model was achieved when items were treated as unique for each country and after a few country-specific items were removed. Conclusion: Clinical collected data from FIM for patients with stroke cannot be pooled in its raw form, or compared across countries. Comparisons can be made after adjusting for country-specific Differential Item Functioning, though the adjustments for Differential Item Functioning and rating scales may not generalize to other samples. [ABSTRACT FROM AUTHOR]

The aim of the study was to survey the use of outcome measures in rehabilitation within Europe. It was envisaged that this would provide the basis for further studies on the cross-cultural validity of outcome measures. A postal questionnaire was distributed in November 1998 to 866 units providing rehabilitation. In total, 418 questionnaires were returned, corresponding to a response rate of 48%. These 418 centres treated an estimated 113000 patients annually, undertaking 360000 assessments. The survey focused on nine diagnostic groups: hip and knee replacement, low back pain, lower limb amputees, multiple sclerosis, neuromuscular disorders, rheumatoid arthritis, spinal cord lesions, stroke and traumatic brain injury. It identified a relatively small number of dominant outcome assessments for each diagnostic group and some variation in the preference for measures across regions. A large number of measures, however, are being used in one or a small number of locations and with relatively few patients. For rehabilitation of orthopaedic patients the majority of assessments undertaken are at the impairment level. For patients with neurological disorders the emphasis is mostly upon measures of disability. [ABSTRACT FROM AUTHOR]

While walking on split-belt treadmills (two belts running at different speeds), the slower limb shows longer anterior steps than the limb dragged by the faster belt. After returning to basal conditions, the step length asymmetry is transiently reversed (after-effect). The lower limb joint dynamics, however, were not thoroughly investigated. In this study, 12 healthy adults walked on a force-sensorised split-belt treadmill for 15 min. Belts rotated at 0.4 m s−1 on both sides, or 0.4 and 1.2 m s−1 under the non-dominant and dominant legs, respectively. Spatiotemporal step parameters, ankle power and work, and the actual mean velocity of the body's centre of mass (CoM) were computed. On the faster side, ankle power and work increased, while step length and stance time decreased. The mean velocity of the CoM slightly decreased. As an after-effect, modest converse asymmetries developed, fading within 2–5 min. These results may help to decide which belt should be assigned to the paretic and the unaffected lower limb when split-belt walking is applied for rehabilitation research in hemiparesis. [ABSTRACT FROM AUTHOR]

In Europe it is common for outcome measures to be translated for use in other languages. This adaptation may be complicated by culturally specific approaches to certain tasks; for example, bathing. In this context the issue of cross-cultural validity becomes paramount.To facilitate the pooling of data in international studies, a project set out to evaluate the cross-cultural validity of impairment and activity limitation measures used in rehabilitation from the perspective of the Rasch measurement model.Cross-cultural validity is assessed through an analysis of Differential Item Functioning (DIF) within the context of additive conjoint measurement expressed through the Rasch model. Data from patients undergoing rehabilitation for stroke was provided from 62 centers across Europe. Two commonly used outcome measures, the Mini-Mental State Examination (MMSE) and the Functional Independence Measure (FIM) motor scale are used to illustrate the approach.Pooled data from 3 countries for the MMSE were shown to fit the Rasch model with only 1 item displaying DIF by country. In contrast, many items from the FIM expressed DIF and misfit to the model. Consequently they were allowed to be unique across countries, so resolving the lack of fit to the model.Where data are to be pooled for international studies, analysis of DIF by culture is essential. Where DIF is observed, adjustments can be made to allow for cultural differences in outcome measurement. [ABSTRACT FROM AUTHOR]

During walking, falling is most likely to occur towards the side of the supporting lower limb during the single stance. Timely lateral redirection of the centre of mass (CoM) preceding the no-return position is necessary for balance. We analysed the curvature peaks (the inverse of the radius of curvature) of the three-dimensional path of the CoM during the entire stride. Twelve healthy adults walked on a force-sensorized treadmill at constant velocities from 0.4 to 1.2 m s−1, in 0.2 m s−1 increments. The three-dimensional displacements of the CoM, the muscular power sustaining the CoM motion with respect to the ground, and the efficiency of the pendulum-like transfer of the CoM were computed via the double integration of the ground reaction forces. The curvatures of the CoM trajectory were measured (Frenet–Serret formula). During the single stance, the curvature showed a bell-shaped increment, lasting a few tenths of a millisecond, and peaking at 365–683 m−1 (radius of 2.7–1.4 mm, respectively), the higher the walking velocity. The CoM was redirected towards the swinging lower limb. The curvature increment was sustained by muscle-driven braking of the CoM. Smoother increments of curvature (peaking at approximately 37–150 m−1), further orienting the CoM towards the leading lower limb, were observed during the double stance. The peaks of the curvatures were symmetric between the two sides. The high curvature peaks during the single stance may represent an index of dynamic balance during walking. This index might be useful for both rehabilitation and sports training purposes. [ABSTRACT FROM AUTHOR]