Kettle Test (KT)

Evidence Reviewed as of before: 22-03-2011
Author(s): Katie Marvin, MSc, PT Candidate
Editor(s): Nicol Korner-Bitensky, PhD OT; Annabel McDermott, OT

Purpose

The Kettle Test was developed as a brief performance-based measure designed to assess cognitive skills in a functional context.

In-Depth Review

Purpose of the measure

The Kettle Test was developed as a brief performance-based measure designed to assess cognitive skills in a functional context. The Kettle Test can be used to evaluate the capacity for independent community living in clients with cognitive impairments. Using the functional task of preparing a hot beverage, the cognitive-functional and problem-solving skills of the client are assessed.

Available versions

The Kettle Test was developed by Dr. Adina Hartman-Maeir, Nira Armon and Dr. Noomi Katz in 2005, and later validated (Hartman-Maeir, Harel & Katz, 2009).

Features of the measure

Items:

The task of preparing two hot beverages is broken down into 13 discrete steps that can be evaluated. These items are described below.

Description of task

The client prepares two cups of hot beverages – one for him/herself and another for the examiner. The examiner asks the client to prepare a hot drink that differs in two ingredients from the one the client chose for him/her self.

  1. Opening the water faucet
  2. Filling the kettle with approximately 2 cups of water
  3. Turning off the faucet
  4. Assembling the kettle
  5. Attaching the electric cord to the kettle
  6. Plugging the electric cord in an electric socket
  7. Turning on the kettle
  8. Assembling the ingredients
  9. Putting the ingredients into the cups
  10. Picking up the kettle when water boils.
  11. Pouring the water into the cups.
  12. Adding milk
  13. Indication of task completion (e.g. verbal, gesture, serving)

What to consider before beginning:

The kettle must be dissembled and equipment set up.

Scoring and Score Interpretation:

All 13 discrete steps of the task are to be scored on a 4-point scale. The total score ranges from 0 to 52 with higher scores indicating the need for greater assistance. The administrator should note any cueing provided to the client in the “comments” section.

The following scoring scale should be used:

  • 0 = Performance intact.
  • 1 = Item completed independently but completed slowly, by trial and error and/or performance was questionable.
  • 2 = Received general cues
  • 3 = Received specific cueing; or
  • Performance was incomplete (for example, only places part of ingredients in cup, removes the kettle before water boils etc.); or
  • Performance is deficient (for example, places lid of kettle upside down, uses wrong ingredients or fails to perform step, for example did not turn on kettle, did not add milk etc.)
  • 4 = Received physical demonstration or assistance.

Following performance, the client and administrator are ask to comment on the following:

  1. Description of the process by the examiner.
  2. Recall of the instructions by the client: “What were the steps you had to do?”
  3. The client’s description of the process: “Describe to me what you did from the beginning to the end of the task.”
  4. Rating of performance by the client: “How do you rate your performance on this task between 0 to 100 percent?” (If the client cannot rate his/her performance then suggest the following options: “very good”, “fair”, “not so good”, “not good at all”).
  5. Rating of difficulty by the client: “How difficult was the task for you? Easy (able to by yourself easily); a little difficult; or very difficult (I needed help)”.
  6. Additional comments

Please note that as with most tests that involve everyday problem solving tasks, immediate learning may occur which may impact performance on retesting.

Time:

The average completion time has not been reported, however, it is estimated that the Kettle Test takes approximately 5-20 minutes to complete.

Training requirements:

There is no formal training required to administer the Kettle Test, however the examiner should have some experience and training in observational evaluation of functional performance. Familiarity with the process and scoring is also recommended.

Subscales:

None typically reported.

Equipment:

  • Electric kettle: it is important to use a kettle that can be dissembled because assembly of the kettle is part of the task.
  • Ingredients for beverages (e.g. instant/decaffeinated coffee, black/herbal tea, sugar/artificial sweeteners, milk, honey)
  • Other ingredients (to be used to distract the client, e.g. salt, pepper, oil)
  • Tray
  • Dishes and utensils for use during the task, plus extra to distract the client (3 cups, milk pitcher, a bowl, 2 plates, 3 tea spoons, a large spoon, 2 forks, a knife, can opener)

Alternative form of the KT

There are no alternative versions of the Kettle Test.

Client suitability

Can be used with:

  • Clients with stroke, who were living independently in the community prior to stroke.
  • Clients with stroke who understand spoken or written language.

Should not be used in:

  • Clients who do not understand spoken or written language.
  • Since the Kettle Test is administered through direction observation of a task a proxy respondent cannot complete it.

In what languages is the measure available?

The manual has only been released in English (Hartman-Maeir, Armon & Katz, 2005), however, only comprehension of spoken language is required of the client during administration.

Summary

What does the tool measure? The Kettle Test measures cognitive skills in a functional context.
What types of clients can the tool be used for? Clients with stroke who were living independently in the community prior to stroke
Is this a screening or assessment tool? Assessment tool
Time to administer Approximately 5 to 20 minutes.
Versions There are no alternative versions.
Other Languages None
Measurement Properties
Reliability
  • No studies have examined the internal consistency of the Kettle Test.
  • No studies have examined the test-retest reliability of the Kettle Test.
  • No studies have examined the intra-rater reliability of the Kettle Test.
  • One study examined the inter-rater reliability of the Kettle Test and reported excellent inter-rater.
Validity

Construct:

Convergent:

One study reported excellent correlation with the Functional Independence Measure (FIM) Cognitive scale and adequate correlation with the Mini-Mental Status Examination (MMSE), Clock Drawing Test and the Behavioural Inattention Test (BIT) Star Cancellation subtest.

Known groups:

The Kettle Test was able to discriminate clients with stroke from healthy controls.

Floor/Ceiling Effects Not yet examined in a stroke population.
Does the tool detect change in patients? Not yet examined in a stroke population.
Acceptability The Kettle Test is accepted by clients with stroke as it involves a real-life functional task.
Feasibility The administration of the Kettle Test is easy and quick to perform.
How to obtain the tool? A preliminary version of the Kettle Test manual can be obtained from: https://www.sralab.org/rehabilitation-measures/kettle-test

Psychometric Properties

Overview

We conducted a literature search to identify all relevant publications on the psychometric properties of the Kettle Test. We identified only one study on the psychometric properties of the Kettle Test, which was published in part by the developers of the measure. More studies are required before definitive conclusions can be drawn regarding the reliability and validity of the Kettle Test.

Floor/Ceiling Effects

Not yet examined in a stroke population.

Reliability

Internal Consistency:

Not yet examined in a stroke population.

Test-retest:

Not yet examined in a stroke population.

Intra-rater:

Not yet examined in a stroke population.

Inter-rater:

Hartman-Maeir, Harel & Katz (2009) examined the inter-rater reliability of the Kettle Test in 21 clients with stroke admitted to one of two rehabilitation hospitals. Clients were within 1-month post stroke and had been living independently prior to stroke. Inter-rater reliability between four Occupational Therapists, as measured using Spearman correlation coefficient was found to be excellent at both sites (r=.851, p=.001; and r=.916, p=.000).

Validity

Content:

Not yet examined in a stroke population.

Criterion:

Concurrent.

Not yet examined in a stroke population.

Predictive:

Not yet examined in a stroke population.

Construct:

Convergent/Discriminant:

Hartman-Maeir, Harel & Katz (2009) examined the convergent validity of the Kettle Test by comparing it to other commonly used measures of cognitive ability in 36 clients with stroke and 36 healthy controls. Correlations were calculated using Pearson Correlation Coefficients. Excellent correlation was found between the Kettle Test and the Cognitive domain of the Functional Independence Measure (FIM) (r=-.659). Adequate correlations were found between the Kettle Test and the Mini-Mental Status Examination (MMSE), Clock Drawing Test and the Behavioural Inattention Test (BIT) Star Cancellation subtest (r=-.478; r=-.566; and r=-.578 respectively).

Known groups:

Hartman-Maeir, Harel & Katz (2009) verified the ability of the Kettle Test to discriminate between healthy controls (n=36) and individuals with stroke (n=36). The healthy controls showed little variability in performance and all scored within a narrow range of 0 to 3 points. The individuals with stroke demonstrated great variability in performance and scored within a large range of 1 to 29 points (with higher scores indicating greater need for assistance). The patients with stroke required significantly more assistance in completing the Kettle Test whereas the healthy controls required very minimal to no assistance.

Ecological:

Hartman-Maeir, Harel & Katz (2009) investigated the ecological validity of the Kettle Test in 36 patients with stroke. Basic activities of daily living (BADL) and safety were measured prior to discharge home, using the Motor domain of the Functional Independence Measure (FIM) and the Safety Rating Scale portion of the Routine Task Inventory (RTI-E) (Allen, 1989; Katz 2006). One month later instrumental activities of daily living (IADL) were assessed using the IADL Scale (Lawton & Brody, 1969). The Kettle Test was found to have excellent correlation with the Motor domain of the FIM (r=-.759) and adequate correlation with the Safety Rating Scale of the RTI-E and the IADL Scale (r=-.571 and r=-.505 respectively), using Pearson correlation coefficients. The results of this study suggest that performance on the Kettle Test is representative of the functional outcome of patients who are discharged to home.

Responsiveness

Not yet examined in a stroke population.

References

  • Hartman-Maeir, A., Armon, N. & Katz, N. (2005). The Kettle Test: A cognitive functional screening test. Unpublished protocol. Helene University, Jerusalem, Israel. Retrieved on February 1, 2010 from: http://www.rehabmeasures.org/Lists/RehabMeasures/DispForm.aspx?ID=939
  • Hartman-Maeir, A., Harel, H. & Katz, N. (2009). Kettle Test – A brief measure of cognitive functional performance: Reliability and validity in a stroke population. American Journal of Occupational Therapy, 64, 592-599.

See The Measure

How to obtain the Kettle Test?

https://www.sralab.org/rehabilitation-measures/kettle-test

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