Essay Example on Conceptual Scheme of the Domains and Variables Involved in a Quality of Life Assessment








Each domain of health has many components like symptoms ability to function and disability that need to be measured Because of this multidimensionality Fig 1 there is an almost infinite number of states of health all with differing qualities and all quite independent of longevity Figure 1 Conceptual Scheme of the Domains and Variables Involved in a Quality of Life Assessment x axis represents subjective perceptions of health y axis objective health status Coordinates Q X Y the actual quality of life and Z measurement of the actual quality of life associated with a specific component e g positive affect or domain e g the psychological domain Measuring quality of life Translating the various domains and components of health into a quantitative value that indicates the quality of life is a complex procedure drawing their tenants from the fields of clinimetrics 20 psychometrics and clinical decision theory Usually most of the researchers measure each quality of life domain individually by asking specific questions related to its most important components By asking a simple question such as Please rate your quality of life or overall health on a scale from 1 to 10 although it may provide a useful global assessment leaves quality of life and overall health ambiguously defined and the quantity being measured too vague to be interpreted more exactly Relying purely on data indicating objective health status such as physicians reports of symptoms omits such relevant factors as a persons threshold for the tolerance of discomfort 21 Variation among quality of life questionnaires is often related to the degree to which they emphasize objective as compared with subjective dimensions the extent to which various domains are covered and the format of the questions rather than differences in the basic definition of quality of life Constructing scales of measurement As we know that many components of quality of life cannot be observed directly they are typically evaluated according to the classic principles of item measurement theory 22

According to this theory the true quality of life value Q cannot be measured directly but it can be measured indirectly by asking a series of questions known as items each of which measures the same true concept or construct These set of questions are then asked to the patient and the answers are converted to numerical scores that are then combined to yield scale scores which may also be combined to yield domain scores or other statistically computed summary scores 23 If all the selected items have been chosen properly the resulting scale of measurement Z should differ from the corresponding true value Q only by random error of measurement and should possess several important properties These properties are 1 Coverage The measurement of quality of life should cover each objective and subjective component symptom condition or social role that is important to members of the patient population and susceptible to being affected positively or negatively by interventions 2 Reliability The process of measurement must yield values that are consistent or remain similar under constant conditions even in an extended series of repeated assessments 3 Validity The observed scales should be so valid that is they target and measure what they claim to measure 4 Responsiveness

Responsiveness is a measure of the association between change in the observed score Z and the change in true value of the construct Q Since quality of life is not directly observable a change in Q also cannot be measured directly So responsiveness is often assessed by changing a criterion variable C 5 Sensitivity Sensitivity refers to the ability of the measurement to reflect true changes or differences in Q Quality of life Selecting an Assessment Instrument The instruments and techniques used to assess quality of life vary according to the identity of the respondent that is whether he or she is a clinician patient relative or care provider the setting of the evaluation and the type of questionnaire used short form self assessment instrument interview clinic based survey telephone query or mail back survey and the general approach to the evaluation Generic instruments are used in general populations to assess a wide range of domains applicable to a variety of health states conditions and diseases 24 25 Disease specific instruments focus on the domains most relevant to the disease or condition under study and on the characteristics of patients in whom the condition is most prevalent 26 28 Disease specific instruments are most appropriate for clinical trials in which specific therapeutic interventions are being evaluated 29 31 The Oral Health Impact Profile OHIP questionnaire is one of the most commonly used instruments it has been used in various studies across different cultures and socio demographic profiles The OHIP was developed in order to provide a comprehensive measurement of the dysfunction discomfort and disability associated with oral conditions as reported by the individual 32 33 OHIP analyzes the different dimensions of functional patterns These dimensions are functional limitation e g difficulty chewing pain e g sensitivity of teeth psychological discomfort e g personal embarrassment physical disability e g changes in diet psycho logical disability e g reduced concentration social disability e g avoiding social contact and incapacitation e g being unable to work productively 33 34 In 1997 Slade described an abridged version of the OHIP called OHIP 14 which was derived from the original version OHIP 49 32 Among the 14 questions of OHIP 14 relate to the psychological and behavioral impact and four address each of the remaining general dimensions Therefore OHIP 14 can be considered one of the best detectors of the psychosocial impact in a population

Write and Proofread Your Essay
With Noplag Writing Assistance App

Plagiarism Checker

Spell Checker

Virtual Writing Assistant

Grammar Checker

Citation Assistance

Smart Online Editor

Start Writing Now

Start Writing like a PRO