Visual Analogue Scale
Original Editor - Venus Pagare
Top Contributors - Venus Pagare, Kim Jackson, Khloud Shreif, Evan Thomas, Rebecca Willis, Scott Buxton, Vanessa Rhule, Lauren Lopez, Melissa Coetsee, Admin and WikiSysop
Introduction[edit | edit source]
A Visual Analogue Scale (VAS) is a measurement instrument that tries to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured[1]. It is often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title For example, the amount of pain that a patient feels ranges across a continuum from none to an extreme amount of pain.[1] From the patient's perspective this spectrum appears continuous ± their pain does not take discrete jumps, as a categorization of none, mild, moderate and severe would suggest. It was to capture this idea of an underlying continuum that the VAS was devised.[1]
Structure and Orientation of the Scale[edit | edit source]
The most simple VAS is a straight horizontal line of fixed length, usually 100 mm. The ends are defined as the extreme limits of the parameter to be measured (symptom,pain,health)orientated from the left (worst) to the right (best). In some studies,horizontal scales are orientated from right to left ,and many investigators use vertical VAS. Scott and Huskisson reported no difference between horizontal and vertical VAS in a survey involving 100 subjects but other authors have suggested that the two orientations differ with regard to the number of possible angles of view. Reproducibility has been shown to vary along a vertical 100-mm VAS and along a horizontal VAS. The choice of terms to define the anchors of a scale has also been described as important.
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They are generally completed by patients themselves but are sometimes used to elicit opinions from health professionals.VAS are more sensitive to small changes than are simple descriptive ordinal scales in which symptoms are rated,for example, as mild or slight,moderate,or severe to agonizing.
Administration[edit | edit source]
The patient marks on the line the point that they feel represents their perception of their current state. The VAS score is determined by measuring in millimetres from the left hand end of the line to the point that the patient marks.[1]
