The Transtheoretical Model of Change has been proven very effective in explaining both the acquisition and cessation of many health related behaviors. In this study, this model was applied to the ...domain of immoderate alcohol use among adolescents (usually drinking three or more drinks per occasion). Measures for two constructs of the model were developed: Stage of Change and Decisional Balance. A total of 853 tenth and eleventh graders who attend vocational training programs were administered a 37-item decisional balance questionnaire and a 5-item staging measure. A short (16-item) psychometrically sound Decisional Balance Inventory was developed based on an exploratory factor analysis that identified two factors, the Pros and Cons of Alcohol Use. The factor structure was confirmed using structural modeling techniques on a hold-out sample. Based on a combination of model fit and parsimony considerations, an uncorrelated model was selected (IFI2 = .909). Students were classified into one of nine stages of acquisition or cessation. External validity was established by the significant and meaningful differences between the stages of change on the pros and cons of alcohol use. Implications of this research are discussed.
The impact of adolescent smoking cessation clinics has been disappointing due to low participation rates, high attrition, and low quit rates. This paper describes two computerized self-help ...adolescent smoking cessation intervention programs: 1) a program utilizing the expert system which is based on the transtheoretical model of change and 2) a popular action-oriented smoking cessation clinic program for teens which was modified for computer presentation. High participation rates in the program among 132 smokers demonstrate the high feasibility and acceptability of the programs. Quit rates of up to 20% were observed during the intervention, and an additional 30% made unsuccessful quit attempt(s). The 6-month follow-up findings indicated that adolescents were poorly prepared to maintain abstinence.
Immoderate drinking in college is common and is associated with significant negative sequelae. In this study, measures of Decisional Balance for Immoderate Drinking were developed. This construct is ...proposed to represent the basic decision-making process that is used by students when deciding whether to drink at immoderate levels or not. Furthermore this construct is embedded in a larger model of behavior change, the Transtheoretical Model of Change, which has been shown to be effective in understanding many health-related behaviors across a wide variety of populations. A total of 629 college students were administered a 25-item decisional balance questionnaire in 1993-1994. Exploratory and confirmatory analyses suggested two different solutions, a two-factor solution and a three-factor solution, but did not provide clear evidence for the psychometric superiority of one over the other. The three-factor solution was chosen as it was seen as an elaboration of the two-factor solution, and validity evidence for this solution is presented. The three factors were labeled the Pros, the Cons-Actual, and the Cons-Potential of Immoderate Drinking. The Cons-Actual scale is a measure of negative affective states associated with current drinking whereas the Cons Potential measures the risk of more concrete negative effects of drinking. External validity was established by the significant and meaningful differences on a number of alcohol-related variables including consumption variables, three measures of negative sequelae of immoderate drinking, and Stage of Change, the organizing construct of the Transtheoretical Model of Change.
Automated health behavior interventions that involve discretionary use by patients or consumers over extended periods of time are becoming more common and it is generally assumed that adherence to ...the recommended schedule is related to the impact of the system on users. Yet reasons for use or non-use of such systems have not been carefully explored. An understanding of factors that influence people to use, not use, or underutilize these automated behavioral change and self-care management systems can help in designing systems that are more effective and acceptable to users. Using qualitative research methods, this study explored the experiences of 45 users of a multiple-contact health promotion application with the goal of understanding the major factors that affect patterns of use (frequency of and duration of contact). The in-depth exploration of users’ perceptions and views made possible by the qualitative research methods revealed a number of important themes. Reported reasons for underutilization or non-use were found to be both user-related and system-related. User-related reasons encompassed personal and individual events that prevented or impeded system utilization. System-related reasons included those that related to the medium itself as well as the content of the application. The qualitative methods employed in this study created a forum through which users’ feedback could be fully explored and then synthesized to assist in the improvement of this and other automated health behavior interventions.
As a growing literature has documented applications of the Transtheoretical Model (TTM) to substance abuse, the utility or futility of such an application has been debated widely. The purpose of this ...paper is to critically examine the TTM, and its conceptual and empirical applications to the field of substance abuse. This review focuses not only on the stage of change dimension of the TTM, but also the processes, decisional balance, and self-efficacy dimensions, which have received less attention in earlier reviews. Particular emphasis is placed on the measurement and conceptualization of the stage of change construct. Unanswered questions and directions for future research are identified. It is concluded that, to effectively determine the TTM's applicability to substance abuse, all dimensions must be more fully developed, validated and evaluated across a range of substance abuse problems. Further, prospective studies are needed to determine the predictive utility of the TTM, and evaluation of TTM-matched interventions will help to address the model's specificity. Migneault JP, Adams TB, Read JP. Application of the Transtheoretical Model to substance abuse: historical development and future directions. Drug Alcohol Rev 2005;24:437-448
Flight simulators are expensive devices that airlines use to train their pilots. Currently, the instructor interact with the simulator through touch screens. We analyzed how a voice driven interface ...can improve the trainer's interaction time efficiency and fluency with the simulator. Real training scenarios were analyzed and 12 representative tasks were chosen for this study. Time comparisons between the voice driven interface and two touch screen interfaces are reported. Twenty voice commands have been derived from the 12 tasks. The analysis of task completion time for touch screen is based on a model-based approach that relieves us from having users performing tasks with the interfaces, the KLM-GOMS model. Results show an average execution time gain of 33.8% using voice commands compared to touch screen commands. However, even though the majority of commands have faster input time for the voice activated interface, some are faster to enter through the touch screen, which suggests that an interface that allows both types of interaction mode might be best.
Some studies of computerized interviews particularly those that deal with personally sensitive topics demonstrate that people have a preference for automated interviews versus live interviews. To ...explore this phenomenon, we administered four open-ended questions after participants were screened for problem drinking by both an automated and a human telephone interviewer. Both interviews administered AUDIT (Alcohol Use Disorders Identification Test) for assessing problem drinking. Individuals were recruited into the study who responded to ads in daily papers. Sixty-two percent of the participants preferred the human interviewer and only 3% among these expressed a concern about confidentiality of the interview. Among the 22% who preferred the automated interview, 32% indicated confidentiality as a reason for their preference.
This study assessed test-retest reliability and criterion validity for an automated version of the Alcohol Use Disorders Identification Test (AUDIT), a screening tool for alcohol-related problems. ...Participants' willingness to use such a system to learn about and change their drinking behavior was also assessed.
Participants were 202 callers recruited through newspaper ads and flyers asking for volunteers concerned about their drinking and willing to help test a new method of screening and referral for alcohol problems. Participants were divided into two groups. The first group of subjects recruited received the Telephone-Linked Communications (TLC)-AUDIT twice, administered a week apart. The second group received the TLC-AUDIT once and a human-administered AUDIT once, also a week apart.
Test-retest reliability was assessed in 102 participants; the intraclass correlation of AUDIT scores between both administrations was .87; kappa for nonproblem versus problem drinking (AUDIT score of 8 or above) was .89. The validity study compared the TLC-AUDIT scores of the next 100 participants to AUDIT questions administered by a human interviewer. The intraclass correlation was .94; kappa was .75. Seventy-five percent of all participants who screened positive for problem drinking agreed they would "talk to a computer again to learn more about your drinking pattern and how to deal with it".
Automated telephone technology can be used to administer the AUDIT instrument with high levels of reliability and validity. This technology could be used to deliver behavioral change interventions.
Glutaraldehyde possesses unique characteristics that render it one of the most effective protein crosslinking reagents. It can be present in at least 13 different forms depending on solution ...conditions such as pH, concentration, temperature, etc. Substantial literature is found concerning the use of glutaraldehyde for protein immobilization, yet there is no agreement about the main reactive species that participates in the crosslinking process because monomeric and polymeric forms are in equilibrium. Glutaraldehyde may react with proteins by several means such as aldol condensation or Michael-type addition, and we show here 8 different reactions for various aqueous forms of this reagent. As a result of these discrepancies and the unique characteristics of each enzyme, crosslinking procedures using glutaraldehyde are largely developed through empirical observation. The choice of the enzyme-glutaraldehyde ratio, as well as their final concentration, is critical because insolubilization of the enzyme must result in minimal distortion of its structure in order to retain catalytic activity. The purpose of this paper is to give an overview of glutaraldehyde as a crosslinking reagent by describing its structure and chemical properties in aqueous solution in an attempt to explain its high reactivity toward proteins, particularly as applied to the production of insoluble enzymes.
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