Hierarchical structure in ADL and IADL: analytical assumptions and applications for clinicians and researchers.

The results of a Canadian study have shown that a set of 12 (I)ADL items did not meet the criteria of Guttman's scalogram program, questioning the assumption of hierarchical ordering. In this article, the hierarchical structure of (I)ADL items from the Canadian elderly sample is retested with another scalogram program, and both the epidemiological research and clinical applications of hierarchical scales are discussed. For retesting the hierarchical structure, Mokken's Stochastic Scale Program was used. When item distributions were not too skewed, the existence of one general dimension with two (correlated) subdimensions were clearly found. The analyses for scalability showed that, except in the case of extremely skewed item distributions, the data set met the criteria of Mokken's Stochastic Scale Program, indicating a hierarchical structure of the items. The scalability of a set of items is affected by the sample studied, the choice of response options for each item, the selection and number of items in the scale, and the type of scaling procedure. The practical assumptions of hierarchy should be restricted to program planning and epidemiological research purposes only. For clinical assessment, a finer grading is desirable and all questions on an ADL/IADL inventory should be asked for each individual.

The Activities-specific Balance Confidence (ABC) Scale.

BACKGROUND: This study provides a replication of the Falls Efficacy Scale (FES) and a head-to-head comparison with the Activities-specific Balance Confidence (ABC) Scale designed to include a wider continuum of activity difficulty and more detailed item descriptors. METHODS: Items for the newly developed 16-item ABC Scale were generated by 15 clinicians and 12 elderly outpatients. Psychometric testing involved 60 community seniors (aged 65-95) self-classified as either high or low in mobility confidence according to their perceived need for a walking aid and personal assistance to ambulate outdoors. RESULTS: Both the FES and ABC scales were found to be internally consistent and demonstrated good test-retest reliability, convergent and criterion validity. Scalogram analyses indicated a stronger cumulative scale in the case of the ABC and skewness in the distribution of FES scores. While both scales were able to discriminate between the two mobility groups, the ABC scale was a more efficient discriminator and yielded a wider range of responses. CONCLUSIONS: The present study provided additional psychometric support for the FES. However, the greater item responsiveness of the ABC scale makes it more suitable to detect loss of balancing confidence in more highly functioning seniors. Greater situation-specificity of items may also assist clinicians in targeting appropriate interventions.

Psychological indicators of balance confidence: relationship to actual and perceived abilities.

BACKGROUND: This study compares several psychological indicators of balance confidence in relation to physical performance, past and current experience, gender bias, and other perceptions of daily functioning. METHODS: Sixty community-dwelling ambulatory elders (aged 65-95) were administered the Falls Efficacy Scale (FES), the Activities-Specific Balance Confidence Scale (ABC), and three dichotomous questions on fear of falling, activity avoidance, and perceived need for personal assistance to ambulate outdoors. Performance measures on walking (average speed) and balance (static posturography) were obtained on a subsample of 21 subjects. RESULTS: Balance confidence assessed by the ABC and self-perceived need for personal assistance with outdoor ambulation were the only indicators significantly associated with the performance measures. As expected, perceived balance capabilities were more strongly related to current behavior (frequency of doing specific activities) than to past experience (fall history). Gender differences in self-report emerged for the global fear-of-falling indicator but not for the two efficacy ratings. CONCLUSIONS: Psychological indicators of balance confidence are important to measure both in conjunction with balance test performance and as a legitimate focus of rehabilitation. Of the various indicators assessed here, the dichotomous fear-of-falling question appears to have the least utility. Perceived need for personal assistance to ambulate outdoors has merit as an initial clinical screening question for discriminating persons on the basis of both physical ability and confidence. The ABC scale appears to have the greatest utility as an evaluative index for older persons at a moderate to high level of functioning.

Temperature Interactions with Growth Regulators and Endogenous Gibberellin-like Activity during Seedstalk Elongation in Carrots.

Stecklings (roots) of three cultivars of carrots (Daucus carota L.) were vernalized 10 weeks at 5 C and subsequently grown at each of three greenhouse night/day temperature regimes: high (27/32 C), medium (21/27 C), and low (15/21 C). Floral differentiation occurred first in the easy bolting cv. Scarlet Nantes, intermediate in cv. Danvers 126, and last in cv. Royal Chantenay. Stem elongation arising from the subapical meristematic region always preceded floral differentiation. Extractable gibberellin-like activity in carrot stem apices increased from harvest during the 10-week vernalization period, then remained constant even though floral differentiation and stem elongation occurred during an additional 20-week cold storage period. Low temperature had both an inductive and a direct effect on reproductive development depending on length of low temperature exposure.After 10 weeks vernalization at 5 C, high greenhouse temperature severely reduced ultimate seedstalk height and the endogenous gibberellinlike activity decreased rapidly during the first 3 weeks in the greenhouse. At the low greenhouse temperature, activity remained fairly constant during the 10-week sampling period. Changes in endogenous gibberellinlike activity were related with stem elongation, but not with floral initiation. Exogenous gibberellic acid (GA(3)) applied following vernalization prevented the inhibitory effect of high greenhouse temperature on seedstalk elongation and resulted in seedstalk heights comparable to untreated controls grown at the low greenhouse temperature. Exogenous applications of succinic acid-2,2-dimethylhydrazide and chlormequat reduced seedstalk height of carrot plants grown at the medium and low greenhouse temperatures to that of untreated controls grown at high temperature. Exogenous growth regulators and greenhouse temperature affected seedstalk elongation, but did not affect the number of plants that flowered.

Biological and chemical properties of the epidioxide isomer of abscisic Acid and its rearrangement products.

The growth inhibitory activity of the epidioxide (II), a precursor in the synthesis of abscisic acid (ABA), has been confirmed with additional assay systems. Under physiological conditions the epidioxide is rearranged to give ABA and an isomer of ABA which has probably the structure V. This major product has very low, if any, biological activity. The biological activity of the epidioxide is explained by its partial conversion (about 20%) to ABA. The reaction rate was enhanced by heavy metal ions and decreased by EDTA. At pH 12.5, the decomposition of the epidioxide is slower than it is near neutrality and ABA is the predominant product. In the biological systems studied the activity of the epidioxide can be accounted for by nonenzymatic conversion to ABA.