The Ashworth Scale Or Ashworth Spasticity Scale is an instrument used to assess people's spasticity.
This scale was created in 1964 by Ashworth and later modified by Bahannon and Smith in 1987.
It consists of a clinical scale of subjective assessment. Its main value is that it allows direct measurement of spasticity, by setting the tone from 0 (without increase of volume) to 4 (rigid extremity in flexion or extension).
This instrument has been highly reliable through its modified version both in the evaluation of the Spasticity Of the flexors of the elbow as in the evaluation of the spasticity of the plantar flexors.
What is the Ashworth scale?
The Ashworth scale is a psychometric instrument used to assess muscle spasticity in people.
It was elaborated in 1964 by Ashworth, however, only the modified Ashworth scale elaborated by Bohannon and Smith in 1987 is used today.
This scale is characterized by evaluating spasticity in five main categories (from 0 to 4). The value 0 indicates a total deficit of increased muscle tone, while the value 4 specifies that the affected parts are rigid in both flexion and extension when they passively move.
Ashworth's classic Ashworth scale had only two items (upper limbs and lower limbs), which was why it was an instrument with poor reliability.
In contrast, the modified Ashworth scale includes a total of five items, plus a sub-item for the second scale of the instrument, resulting in a much more reliable tool.
At present, the Ashworth scale stands out as one of the most widely used instruments for assessing muscle spasticity and is a highly used tool in the field of medicine and physiotherapy.
Scale items
The Ashworth Scale presents five major items ranging from 0 to 4, including an additional item on scale 1.
The determination of each of the items of the scale is subjective, so it depends on the personal appreciation of the professional that applies it.
For this reason, it results a heteroadminstrada scale that can not be self-administered by the subject itself nor by personnel not qualified for its use.
The items on the Ashworth scale are as follows:
0. Normal muscle tone
The first item on the scale is used to establish the presence of a totally normal muscular tone in the person. This item implies the total absence of increase of tone in the musculatura.
1. Slight hypertonia
The second item on the scale indicates a slight increase in muscle response to movement, either by flexion or by extension.
This increase in muscle response is visible with palpation or relaxation, and implies minimal resistance at the end of the movement arc.
It constitutes an increase in muscle tone with"stop"in the passive movement of the extremity and a minimum resistance in less than half the arc of movement of the extremity.
1+. Slight increase in muscle resistance to movement
This item serves to complement the previous item. Specifies a slight increase in muscle resistance to flexion or extension motion, followed by minimal resistance throughout the rest of the range of motion.
2. Moderate hypertonia
This fourth item specifies a marked increase in muscle strength during most of the arc of joint movement. However, the joint remains easily moved.
Increased muscle tone is seen during most of the range of motion, although this does not over limit movement of the joint.
3. Intense hypertonia
For the determination of item three of the scale, a marked increase in muscle strength should be witnessed. It connotes a prominent increase of the muscular tone, with difficulty to carry out the passive movements.
4. Extreme Hypertonia
Finally, in this last item the affected parts present a totally rigid state in flexion or extension, and even when they move passively.
Psychometric Properties
The Ashworth Modified Scale has several psychometric studies that have tested its effectiveness and reliability properties to measure spasticity. In this sense, the main characteristics of the scale are:
- It is a reliable, useful and valid instrument as it responds to the passive movement performed by the evaluator to a specific articulation.
- It consists of an evaluative tool that can promote the best evaluation by requiring a quantitative clinical measure of the commitment of spasticity in each patient.
- The Ashworth modified scale has a greater variety of items than the traditional Ashworth scale when evaluated by joints and each person's body. Likewise, both scales differ in the evaluation procedure.
- It allows measuring spasticity over time, making it a good tool to follow up patients with this type of problem.
- It is an instrument that is free of random errors as the differences are close to zero, since the diagnoses two and three have been stable in the different evaluations made.
- The modified Ashworth scale, unlike the traditional scale, is a reliable evaluative instrument in both upper limbs and lower limbs.
- Studies have reported that the scale does not detect significant changes in sensitivity when there is little variability in the degree of spasticity of patients.
- The modified Ashworth scale is a validated instrument for the MSI organization Cali Sections.
- The main limitations of the scale are related to the characteristics of each evaluator, since it consists of a subjective instrument.
References
- Ashworth, B. (1964).sepeap.org.
- Bohannon RW, Smith MB. (1987). Sepeap.org.
- Collazos, Larry; . Physiotherapeutic intervention in patients with Guillan Barre syndrome in each of their stages. THESIS. University of the Valley 2000.
- Vattanasilp W, Ada L. Comparison of the Ashworth scale and clinical laboratory measures to assess spasticity. Aust J. Physiother 1999; 45: 135-139.