Validation by Rasch analysis of the Mania Scale (EMUN) for measuring manic symptions

Introduction. The Mania Scale (EMUN) developed at the Universidad Nacional de Colombia was designed to measure the severity of manic symptoms, but has been validated only using classical psychometric theory. Objectives. The psychometric properties and measuring characteristics of the EMUN scale were determined using an analysis based on item response theory. Materials and methods. Two hundred sixty-four patients with manic, hypomanic or mixed episode symptoms were assessed using the EMUN scale. The psychometric characteristics of the scale were analyzed using a Rasch model for partial credit scoring. Results. The analysis based on the item response theory showed that reliability and separation indexes for persons are low in contrast to items. This suggested a narrow representation of the construct evaluated in this sample. Reduced need to sleep has been the most easily detectable symptom in mania. Excepting depressive affect and distractibility, the majority of items fit the model?s expectation The rating scale diagnostics showed that the average measures increase monotonically across the rating scale. Two items showed redundancy and can be omitted in future versions of the scale. The person-item map suggested that the syndrome is not fully evaluated by the scale, probably because some depressive symptoms are not included. Conclusion. In this first study to use Rasch analysis to assess the psychometric properties of the EMUN scale, misfit and redundancy of items have been detected. The manic syndrome is not fully evaluated by the scale. The instrument can be improved by adding depressive symptoms.     

Internal consistency and convergent and divergent validity of the Liverpool jetlag questionnaire

ABSTRACT

Objective measures of circadian disruption are difficult to capture in a free-living environment hence the importance of validating subjective measures of jetlag. We aimed to assess the internal consistency of the 15-item Liverpool Jetlag Scale and its convergent and divergent validity with indicators of fatigue and anxiety in a large sample of air passengers. Online survey of passengers was conducted after travel on a range of long-haul flights. Jetlag was captured using the Liverpool scale, fatigue was measured using the Vitality subscale of the Short-Form Health Survey (SF-36), and the presence of anxiety or worry before, during, and after flight was self-reported. Inter-item correlations and Cronbach’s alpha were calculated to assess the internal consistency of the scale. Exploratory factor analysis was used to examine whether the scale was consistent with one underlying construct of circadian disruption. Correlations between fatigue and anxiety (flying, situational, symptoms) with jetlag were used to assess convergent and divergent validity. Linear regression was used to determine the most important symptoms contributing to subjective jetlag rating. N = 460 passengers (57% female, mean age 50, SD 16 years) were surveyed. Cronbach’s alpha indicated high internal reliability (alpha = 0.85). Jetlag was more strongly correlated with fatigue (rho = 0.47) than any type of anxiety (rho = 0.10–0.22). Exploratory factor analysis indicated responses were consistent with four factors: (i) fatigue/daytime impairment, (ii) sleep disturbance, (iii) changes in appetite and (iv) changes in bowel function. Regression analysis indicated that only changes in concentration, sleep time, fatigue, sleep quality and frequency of bowel motions were independent correlates of subjective jetlag (R² = 27%). The Liverpool Jetlag Scale is internally consistent and demonstrates the expected relationships with fatigue and anxiety. Patterns of response are not consistent with all items being derived from one underlying factor, i.e. circadian disruption. Further, not all items contributed to the jetlag rating, suggesting the single-item rating may be useful for capturing the subjective experience of jetlag, whilst a total jetlag score is useful for also capturing circadian symptoms considered by passengers to be unrelated to jetlag. Validation of subjective jetlag against objective measures of circadian disruption is required.     

A questionnaire technique for assessing the stress at work

Subjective perception of the stress at work is a phenomenon reflecting the experience-mediated relationship between the sum of objective conditions of work and the sum of individual's traits available to cope with demands of the work environment. This relationship is mirrored in the function of the whole organism and can be described using the formula S = f (E, D), where S = the state of the organism, E = exposure (i.e. the sum of all stressors the organism is exposed to), and D = disposition (i.e. the sum of traits the organism has available to cope with these stressors). Based on these theoretical considerations, a questionnaire has been developed as a tool for assessing the work stress in different groups of occupations. This "Work Stress Assessment" (WSA) questionnaire was used in a group of 4800 female employees from various branches of the printing industry. Of a total of 160 questionnaire items, 98 items were selected and used to assess the workload in these employees, using a 5-point rating scale of evaluation. The responses were processed statistically, separately for 3531 blue-collar and 1269 white-collar respondents. The use of the factor analysis method revealed that the two groups of jobs had 16 factors in common, 3 factors were specific for blue-collar and 2 factors for white-collar jobs. Judged by factor components, the responses of subjects were well structured and the perceived stress at work turned out to well reflect the reality of conditions of work, which confirms the construct validity of this methodical approach based on the subjective perception of occupational stress. High coefficients of consistency (0.959 for blue-collar and 0.946 for white-collar occupations) point to the reliability of this questionnaire technique. Thus, the WSA questionnaire appears to suitably complement the other methodical approaches aimed at assessing the stress at work in different groups of occupations.     

Relationship between Item Responses of Negative Affect Items and the Distribution of the Sum of the Item Scores in the General Population

BackgroundSeveral studies have shown that total depressive symptom scores in the general population approximate an exponential pattern, except for the lower end of the distribution. The Center for Epidemiologic Studies Depression Scale (CES-D) consists of 20 items, each of which may take on four scores: “rarely,” “some,” “occasionally,” and “most of the time.” Recently, we reported that the item responses for 16 negative affect items commonly exhibit exponential patterns, except for the level of “rarely,” leading us to hypothesize that the item responses at the level of “rarely” may be related to the non-exponential pattern typical of the lower end of the distribution. To verify this hypothesis, we investigated how the item responses contribute to the distribution of the sum of the item scores.MethodsData collected from 21,040 subjects who had completed the CES-D questionnaire as part of a Japanese national survey were analyzed. To assess the item responses of negative affect items, we used a parameter r, which denotes the ratio of “rarely” to “some” in each item response. The distributions of the sum of negative affect items in various combinations were analyzed using log-normal scales and curve fitting.ResultsThe sum of the item scores approximated an exponential pattern regardless of the combination of items, whereas, at the lower end of the distributions, there was a clear divergence between the actual data and the predicted exponential pattern. At the lower end of the distributions, the sum of the item scores with high values of r exhibited higher scores compared to those predicted from the exponential pattern, whereas the sum of the item scores with low values of r exhibited lower scores compared to those predicted.ConclusionsThe distributional pattern of the sum of the item scores could be predicted from the item responses of such items.     

Life events assessment of depressed patients: a comparison of self-report and interview formats

Both self-report questionnaires and semi-structured interviews have been employed in past research on the association between life events and psychiatric disorder. We examined the comparability of these two approaches by giving both a self-report life events scale and semi-structured life events interview to 38 depressed patients. About 40% of the items noted on the interview were missed when using the questionnaire. Approximately 15% of the items noted on the questionnaire were errors since the events did not meet the definition or time criteria specified in the questionnaire. Twenty percent of the items noted on the questionnaire were not noted on the interview and may represent underinclusiveness on the part of the interview. The implications of these differences were examined by comparing the association between a variety of demographic and clinical variables and life events under each methodology. There were no significant differences between the two methods except when examining the association between life events and other subjective self-report measures.     

Three-year follow-up on clinical symptoms and health-related quality of life after reduction mammaplasty

The present study evaluated changes in patient health status and health-related quality of life 3 years after reduction mammaplasty. A previous investigation in the same study population of 49 women showed significant reduction of pain and subjective problems and improvement in health-related quality of life 6 and 12 months after the operation. The present article presents results on the health status and quality of life preoperatively and at 1 and 3 years after reduction mammaplasty. The same questionnaires were used regarding pain scored in six different locations (on a 10-point grading scale), subjective problems related to the size and weight of the breast (on a six-point grading scale), expectations of the operation (on a six-point grading scale), and health-related quality of life (with the Medical Outcomes Study 36-Item Short-Form Health Survey, or Short Form-36). The 39 women who answered the questionnaire (response rate, 80 percent) scored minor nonsignificant changes in pain between the 1- and 3-year assessments, but the reduction of pain was still significant (p < 0.001) compared with preoperative scores. The same applied for the patients' subjective problems, with no statistically significant changes between the 1- and 3-year assessments. Thus, the initially scored postoperative improvement (p < 0.001 for all items except sleep) remained. Three years after the operation, the patients' preoperative expectations were still fulfilled. There were minor differences between the 1-year and the 3-year health-related quality-of-life scores (Short Form-36), but these were all without statistical significance. Compared with preoperative scores, major improvement was still found for all sub-scales (p < 0.05 to p < 0.001) except "role physical." Reduction mammaplasty is an efficient remedy for pain and physical and psychological problems associated with macromastia. The improvements noted directly after the reduction mammaplasty remain stable and are, as judged by patient questionnaires and quality-of-life scores, of long-standing clinical importance.     

The interrelationship among achievement patterns of activities of daily living for institutionalized dependent elderly

The purpose of the present study was to examine the interrelationship of achievement patterns between 74 activities by selecting nine ADL domains, including 27 items used in existing ADL index for the institutionalized disabled elderly (Disabled-ADL). For these 74 ADL items, 706 institutionalized dependent elderly were assessed using a dichotomous scale of "possible" or "impossible" by staff working at the subjects' institutions. The difficulty of each item was examined by calculating the proportion of "possible" responses. The interrelationships among activities were determined by calculating phi coefficients. Furthermore, the degree of agreement assessed between ADL items was calculated by dividing the total response by the number of "possible-possible" and "impossible-impossible" responses, in order to examine the similarity of the achievement pattern of ADL. The phi coefficient values were high among ADL items with comparable difficulty where the item proportions were within about 10%. Even if belonging to a different ADL domain, the relationship was high among ADL items with similar difficulty and kinds of activity. All of the 27 activities used in Disabled-ADL indicated high agreement of over 80% with one or more activities among the other 47 activities used in this study. Especially, three lower extremity activities of "putting on trousers while standing", "going up and down stairs" and "squatting down from a standing posture" agreed more than 90% with many other lower extremity activities. The possibility is suggested in determining lower extremity functional levels by assessing these three activities. The selection of ADL items considering these influences is necessary to comprehensively assess ADL ability of disabled elderly.     

Measurement of global self-esteem in dementia. Reliability and validity of Brinkman's self-esteem scale

In a person-centered approach to dementia-care, the self-concept of people suffering from dementia receives more and more attention. There is, however, a lack of direct measures of self-esteem, which is the evaluative component of the self-concept. An 8-item scale to tap global self-esteem was administered to 245 consecutive visitors of a psychogeriatric day care centre. Mokken scale analysis revealed a scalability coefficient of H = 0.44, which is in the medium range. The item responses were explained by a double monotonicity model, allowing for a reliable ordering of subjects and items on the latent trait 'self-esteem'. One-week test-retest reliability on the self-esteem scale was 0.68. Scalability and reliability were about equal across subgroups differing in severity of dementia. Patients were asked to give themselves a rating (1-10) for their estimated sense of self-worth. These ratings correlated 0.55 with scores on the self-esteem scale. Self-esteem was negatively related to measures of depression, fatigue and loneliness, but not to the level of cognitive impairment of the patient. As an independent measure of subjective well-being, self-esteem deserves particular attention in the assessment and treatment of dementia patients.     

Ineffectiveness of Reverse Wording of Questionnaire Items: Let’s Learn from Cows in the Rain

Objective

We examined the effectiveness of reverse worded items as a means of reducing or preventing response bias. We first distinguished between several types of response bias that are often confused in literature. We next developed arguments why reversing items is probably never a good way to address response bias. We proposed testing whether reverse wording affects response bias with item-level data from the Multidimensional Fatigue Inventory (MFI-20), an instrument that contains reversed worded items.

Methods

With data from 700 respondents, we compared scores on items that were similar with respect either to content or to direction of wording. Psychometric properties of sets of these items worded in the same direction were compared with sets consisting of both straightforward and reversed worded items.

Results

We did not find evidence that ten reverse-worded items prevented response bias. Instead, the data suggest scores were contaminated by respondent inattention and confusion.

Conclusions

Using twenty items, balanced for scoring direction, to assess fatigue did not prevent respondents from inattentive or acquiescent answering. Rather, fewer mistakes are made with a 10-item instrument with items posed in the same direction. Such a format is preferable for both epidemiological and clinical studies.     

Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS): Reliability,initial validity and normative scores in higher education students

Based on successive samples totaling more than 5000 higher education students, we scrutinized the reliability, structure, initial validity and normative scores of a brief self-report seven-item scale to screen for the continuum of nighttime insomnia complaints/perceived sleep quality, used by our team for more than a decade, henceforth labeled the Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS). In study/sample 1 (n?=?1654), the items were developed based on part of a larger survey on higher education sleep–wake patterns. The test–retest study was conducted in an independent small group (n?=?33) with a 2–8 week gap. In study/sample 2 (n?=?360), focused mainly on validity, the BaSIQS was completed together with the Pittsburgh Sleep Quality Index (PSQI). In study 3, a large recent sample of students from universities all over the country (n?=?2995) answered the BaSIQS items, based on which normative scores were determined, and an additional question on perceived sleep problems in order to further analyze the scale’s validity. Regarding reliability, Cronbach alpha coefficients were systematically higher than 0.7, and the test–retest correlation coefficient was greater than 0.8. Structure analyses revealed consistently satisfactory two-factor and single-factor solutions. Concerning validity analyses, BaSIQS scores were significantly correlated with PSQI component scores and overall score (r?=?0.652 corresponding to a large association); mean scores were significantly higher in those students classifying themselves as having sleep problems (p?<?0.0001, d?=?0.99 corresponding to a large effect size). In conclusion, the BaSIQS is very easy to administer, and appears to be a reliable and valid scale in higher education students. It might be a convenient short tool in research and applied settings to rapidly assess sleep quality or screen for insomnia complaints, and it may be easily used in other populations with minor adaptations.     

Assessing the consultation: method for measuring changes in patient stress and arousal.

A method has been developed to assess anxiety levels in terms of stress and arousal in patients before and after a consultation with a general practitioner. The MACL self report mood scale has been used in hospital outpatient studies. An adaptation of the scale using 26 items of low vocabulary was applied to general practice patients in a novel way to show appreciable reductions in stress and increases in arousal after consultations. Since arousal is related to efficiency of performance and stress has been inversely related to recall of information given in the consultation factors that affect stress and arousal in patients could usefully be identified.     

Psychometric properties of the Danish Strength and Difficulties Questionnaire: the SDQ assessed for more than 70,000 raters in four different cohorts

Background

The Strength and Difficulties Questionnaire (SDQ) is a brief behavioural five factor instrument developed to assess emotional and behavioural problems in children and adolescents. The aim of the current study was to evaluate the psychometric properties for parent and teacher ratings in the Danish version of SDQ for different age groups of boys and girls.

Methods

The Danish versions of the SDQ were distributed to a total of 71,840 parent and teacher raters of 5-, 7- and 10- to 12-year-old children included in four large scale Danish cohorts. The internal reliability was assessed and exploratory factor analyses were carried out to replicate the originally proposed five factor structure. Mean scores and percentiles were examined in order to differentiate between low, medium and high levels of emotional and behavioural difficulties.

Results

The original five factor structure could be substantially confirmed. The Conduct items however did not solely load on the proposed Conduct scale and the Conduct scale was further contaminated by non-conduct items. Positively worded items tended to load on the Prosocial scale. This was more so the case for teachers than for parents. Parent and teacher means and percentiles were found to be lower compared to British figures but similar to or only slightly lower than those found in the other Nordic countries. The percentiles for girls were generally lower than for boys, markedly so for the teacher hyperactivity ratings.

Conclusions

The study supports the usefulness of the SDQ as a screening tool for boys and girls across age groups and raters in the general Danish population.     

The influence of gender, athletic events, and athletic experience on the subjective dominant hand and the determination of the dominant hand based on the laterality quotient (LQ) and the validity of the LQ

This study aimed to reveal the influence of gender, athletic events and athletic experience on the subjective dominant hand and the dominant hand based on the laterality quotient (LQ). It also aimed to examine the validity of the Edinburgh Inventory (Oldfield, 1971). Males and females (n=3,726) living in 7 prefectures in Japan (age: 16-45 yrs) participated in this survey. Analysis was performed on 3,557 separate datasets with high reliability. The reliability of the survey was examined using a test-retest method consisting of 100 people selected randomly from all participants. All participants provided the same answers for each question. The influence of gender, event and experience was examined for the subjective and LQ-based dominant hands. In addition, concordance rates of the subjective dominant hand and the LQ-based dominant hand and both dominant hands were examined. Differences of concordance rates between hands used in the 10 movement questions of the Inventory and the subjective dominant hand were tested using the chi(2) test. The frequency differences among items were tested using Ryan's method (multiple comparisons). Significant gender differences were found between rates of the LQ-based dominant hand (males: 94.4%; females: 96.6%) and the subjective dominant hand (males: 91.6%; females: 94.0%), but the degree was only 2.0-4.0%. Insignificant differences were found among athletic events, two groups of different athletic experience, and gender according to each athletic event. The subjective dominant hand almost always agreed with the LQ-based dominant hand (complete concordance rate=0.96, kappa=0.67). Of the 10 question items, inexperienced answers were found only in the item "Knife (without fork)". The "Toothbrush", "Broom (upper hand)", and "Opening box (lid)" items had significantly lower correspondence with the subjective dominant hand (79.7-87.0%) than the other items (92.1-95.7%).In conclusion, athletic experience appears to have little influence on handedness, although there is a slight gender difference. The subjective dominant hand almost always agrees with the dominant hand based on the Inventory. A more efficient handedness inventory may be constructed by excluding the above 4 items.     

Using a Polygraph System for Evaluation of the Social Desirability Response Bias in Self-Report Measures of Aggression

Empirical evidence suggests that respondents systematically overreport socially desirable behaviors and systematically underreport socially undesirable behaviors. This “social desirability response bias (SDRB)” presents significant challenges for research that relies on self-report measures to assess behaviors that adhere to or violate social norms. The present study used a state-of-the-art polygraph system to examine SDRB in widely used aggression questionnaires, including the Buss–Perry Aggression Questionnaire-Short Form, the Indirect Aggression subscale of the Aggression Questionnaire by Western Psychological Services, and the Reactive–Proactive Questionnaire. Sixteen college students with no criminal record, no known prior history of aggressive behavior, and no reported drug abuse, responded to verbally administered forms of the instruments. Indirect aggression items produced the largest, statistically significant physiological response across the sampled channels. The magnitude of this response was negatively and significantly correlated with the self-report ratings of the frequency of such behaviors. The mean separation between physiological (skin conductance) and self-report responses for indirect aggression remained significant and consistent with correlational analyses when both types of responses were converted to the same scale and compared directly. Finally, the relative magnitude of skin conductance response for items assessing indirect aggression was significantly greater than the relative magnitude of skin conductance response for direct aggression. Overall, the study suggests that the use of automated state-of-the art polygraph systems may potentially identify sensitive items on self-report instruments where social responsibility response bias is possible. Implications for the use of this procedure with such instruments are discussed.     

Incorporating temporal variability of stressors into studies: An example using suspension-feeding bivalves and elevated suspended sediment concentrations

While spatial scale is increasingly incorporated into ecological experiments, the effect of temporal scale is explicitly investigated less frequently, despite the potential for temporal-scale dependent results. This study was designed to investigate the effect of variations in stress duration on responses, in a situation where stress duration is driven by natural storm events. Specifically, the utility of combining short-term laboratory and longer-term field transplant experiments in assessing the effect of increased suspended sediment concentrations on suspension-feeding bivalves (Austrovenus stutchburyi and Paphies australis) was tested. Short-term (2 days) feeding responses did not reflect feeding or biomass responses over slightly longer time-scales (8-14 days). Also, stronger biomass responses to suspended sediment concentrations were observed after three months in the field, than after 14 days in the laboratory. For unimodal responses, increased stress duration decreased the peak and shifted its location to lower suspended sediment levels. Using continuous measures of field suspended sediment concentrations, the study was able to determine the temporal scale of variability most related to the response. With such information, field surveys and transplants together make a useful tool, preventing co-occurring factors and changes in the duration and intensity of the factors of interest from obscuring results.     

Habitation and recovery of vascular responses in calf and forearm and of the level of pain sensation during the cold pressor test in man

Forearm and calf blood flow were measured using a mercury-in-silastic gauge during immersion of one foot in water at 4 degrees C. The subjects were asked to assess the level of pain on a scale 0-10. The effects of one session of repeated immersions on the vascular response in the calf, forearm and on subjective pain sensation were studied. In 6 of the 14 subjects vasodilatation was elicited in both forearm and calf during the first immersion. During the first session the vasodilation diminished, while subjective pain sensation remained at the level of 7 on the scale. In 4 subjects vasoconstriction in both calf and forearm occurred during the first immersion. During repeated immersions forearm vasoconstriction subsided, while in the calf it remained at the same level. The level of the subjective pain sensation diminished from 7.5 to 5 in 1 subject. Repeated immersions in six to ten daily sessions led to reduction of vasodilatation in calf and forearm while there was a small change in the pain sensation, i.e. reduction from the level of 6.9 to 5.7 (P less than 0.01). In subjects in whom vasoconstriction in forearm and calf was observed no clear trend in vascular responses was observed during the repeated daily sessions while the pain sensation in 1 subject was reduced from 6 to 4.8. In 3 subjects the change of vascular responses was different in the forearm and calf.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dream intensity scale: Factors in the phenomenological analysis of dreams.

The present study aimed to develop a comprehensive assessment tool for measuring subjective dream intensity by revising the original probes and response scales of the Dream Intensity Inventory and incorporating new variables. The factor analyses suggested that 18 items of the new instrument, Dream Intensity Scale, could form four scales and six subscales. The revision of the probes and response scales did not have major effects on the clustering of the indicator variables, which was highly consistent with the original three-factor measurement model. The alpha coefficients, interitem correlations, and item-scale correlations indicated a good internal consistency for the Dream Intensity Scale. Moreover, the convergent and discriminant concurrent validity of the Dream Intensity Scale and the clinical utility of its scale and subscale scores were substantiated by their selective correlations with neuroticism and extraversion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COMT Val158Met Genotype Selectively Alters Prefrontal [18F]Fallypride Displacement and Subjective Feelings of Stress in Response to a Psychosocial Stress Challenge

Catechol-O-methyltransferase (COMT) plays an essential role in degradation of extracellular dopamine in prefrontal regions of the brain. Although a polymorphism in this gene, COMT Val¹⁵⁸Met, affects human behavior in response to stress little is known about its effect on dopaminergic activity associated with the human stress response, which may be of interest for stress-related psychiatric disorders such as psychosis. We aimed to investigate the effect of variations in COMT genotype on in vivo measures of stress-induced prefrontal cortex (PFC) dopaminergic processing and subjective stress responses. A combined sample of healthy controls and healthy first-degree relatives of psychosis patients (n = 26) were subjected to an [¹⁸F]fallypride Positron Emission Tomography scan. Psychosocial stress during the scan was induced using the Montreal Imaging Stress Task and subjective stress was assessed every 12 minutes. Parametric t-maps, generated using the linear extension of the simplified reference region model, revealed an effect of COMT genotype on the spatial extent of [¹⁸F]fallypride displacement. Detected effects of exposure to psychosocial stress were unilateral and remained restricted to the left superior and right inferior frontal gyrus, with Met-hetero- and homozygotes showing less [¹⁸F]fallypride displacement than Val-homozygotes. Additionally, Met-hetero- and homozygotes experienced larger subjective stress responses than Val-homozygotes. The direction of the effects remained the same when the data was analyzed separately for controls and first-degree relatives. The human stress response may be mediated in part by COMT-dependent dopaminergic PFC activity, providing speculation for the neurobiology underlying COMT-dependent differences in human behaviour following stress. Implications of these results for stress-related psychopathology and models of dopaminergic functioning are discussed.     

Development of Two Barthel Index-Based Supplementary Scales for Patients with Stroke

Background

The Barthel Index (BI) assesses actual performance of activities of daily living (ADL). However, comprehensive assessment of ADL functions should include two other constructs: self-perceived difficulty and ability.

Objective

The aims of this study were to develop two BI-based Supplementary Scales (BI-SS), namely, the Self-perceived Difficulty Scale and the Ability Scale, and to examine the construct validity of the BI-SS in patients with stroke.

Method

The BI-SS was first developed by consultation with experts and then tested on patients to confirm the clarity and feasibility of administration. A total of 306 participants participated in the construct validity study. Construct validity was investigated using Mokken scale analysis and analyzing associations between scales. The agreement between each pair of the scales’ scores was further examined.

Results

The Self-perceived Difficulty Scale consisted of 10 items, and the Ability Scale included 8 items (excluding both bladder and bowel control items). Items in each individual scale were unidimensional (H≥0.5). The scores of the Self-perceived Difficulty and Ability Scales were highly correlated with those of the BI (rho = 0.78 and 0.90, respectively). The scores of the two BI-SS scales and BI were significantly different from each other (p<.001). These results indicate that both BI-SS scales assessed unique constructs.

Conclusions

The BI-SS had overall good construct validity in patients with stroke. The BI-SS can be used as supplementary scales for the BI to comprehensively assess patients’ ADL functions in order to identify patients’ difficulties in performing ADL tasks, plan intervention strategies, and assess outcomes.