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Egen Klassifikation Scale Version 2 (EK2)
Availability
Please email the author for information about obtaining the instrument: Ulla Werlauff, ulwe@muskelsvindfonden.dk/rcfmen
Classification
Supplemental - Highly Recommended: Congenital Muscular Dystrophy*
*Highly recommended for studies analyzing motor function -age limit 2+
 
Exploratory: Duchenne Muscular Dystrophy (DMD), Congenital Duchenne Muscular Dystrophy (CMD) and Spinal Muscular Atrophy (SMA)
Short Description of Instrument
The Egen Klassifikation (EK) scale was designed as a clinical tool to measure functional ability in non-ambulatory DMD and spinal muscular atrophy (SMA). The scale is used to plan and the evaluate effect of interventions.
Comments/Special Instructions
Development of EK 1
The EK1-10 was developed and constructed by Dr Birgit Steffensen and colleagues and several studies on reliability and validity were published between 1995-2002. (Lyager et al., 1995; Steffensen et al., 2001; Steffensen et al., 2002a; Steffensen et al., 2002b) The EK1, a 10-item scale is very responsive to change in persons with DMD. (Connolly et al., 2016)
 
Since the 10-item EK was not as sensitive to change over time in individuals with SMA as in individuals with DMD, seven items were added by an international expert group to the scale expanding it to 17-items. In the EK2, the additional seven items assess abilities related to hand-function, eating and swallowing. (Steffensen et al., 2008)
Scoring and Psychometric Properties
Scoring: Ten-item scale with each item scored in four categories from 0 to 3 based on a face-to-face interview with the person about how the individual items are normally performed. Items assess the patient's ability to use wheelchair, transfer from wheelchair, ability to stand, balance on wheelchair, move arms, use hands/arms for eating, turn in bed, cough, and speak, as well as their physical well-being.
 
The EK-sum score is calculated as the sum of all items; maximum score (30) represents lowest function, and minimum score (0) represents highest function. (Rehabiliterings Center for Muskelsvind, 2023) An EK score of 21 or higher is a predicative of high risk for introduction to noninvasive ventilation in DMD patients.
The 17-item EK2 is also scored by four categories and the revised score with 0 as highest function is the same as for EK1, but the maximum EK2-sum score is 51. (Steffensen et al., 2008)
 
Psychometric Properties: Reliability, validity and sensitivity studies published between 1995-2002, the EK scale was shown to "(1) discriminate between individuals, (2) predict the need of assisted ventilation in DMD, (3) detect change of function as a result of (a) the natural history of the two diseases or (b) scoliosis surgery and spinal bracing." (Steffensen et al., 2008)
When used for scoring video-recorded individuals with DMD, the EK scale has been shown to have high inter- and intra-rater reliability (Intra-class Correlation Coefficient (ICC) = 0.98). (Steffensen et al., 2001)
Rationale/Justification
Strengths: The 10-item EK is very responsive to change in persons with DMD. The EK has been translated into and validated in several languages. (Rehabiliterings Center for Muskelsvind, 2023)
 
Weaknesses: The EK is not as sensitive to change over time in individuals with SMA as in individuals with DMD. (Steffensen et al., 2008)
References
Key References:
Steffensen B, Hyde S, Lyager S, Mattsson E. Validity of the EK scale: a functional assessment of non-ambulatory individuals with Duchenne muscular dystrophy or spinal muscular atrophy. Physiother Res Intl. 2001;6(3):119-134.
 
Steffensen BF, Lyager S, Werge B, Rahbek J, Mattsson E. Physical capacity in non-ambulatory people with Duchenne muscular dystrophy or spinal muscular atrophy: a longitudinal study. Dev Med Child Neurol. 2002a Sep;44(9):623-32.
 
Steffensen BF, Hyde S, Attermann J, Mattsson E. Reliability of the EK Scale, a Functional Test for Non-ambulatory Persons with Duchenne Dystrophy. Adv Physiother. 2002b;4:37-47.
 
Steffensen BF, Mayhew A, Aloysius A, Eagle M, Mercuri E, Messina S, Mazzone E, Nadeau A, Main M, Scott E, Werlauff U, Werge B, Glanzmann AM, Muntoni F. Egen Classification revisited in SMA. Neuromuscul Disord. 2008;18:740-41.
 
Additional References:
Brunherotti MA, Sobreira C, Rodrigues-Júnior AL, de Assis MR, Terra Filho J, Baddini Martinez JA. Correlations of Egen Klassifikation and Barthel Index scores with pulmonary function parameters in Duchenne muscular dystrophy. Heart Lung. 2007 Mar-Apr;36(2):132-9.
 
Connolly AM, Malkus EC, Mendell JR, Flanigan KM, Miller JP, Schierbecker JR, Siener CA, Golumbek PT, Zaidman CM, Mcdonald CM, Johnson L, Nicorici A, Karachunski PI, Day JW, Kelecic JM, Lowes LP, Alfano LN, Darras BT, Kang PB, Quigley J, Pasternak AE, Florence JM; MDA DMD Clinical Research Network. Outcome reliability in non-ambulatory boys/men with Duchenne muscular dystrophy. Muscle Nerve. 2015 Apr;51(4):522-32.
 
Connolly AM, Florence JM, Zaidman CM, Golumbek PT, Mendell JR, Flanigan KM, Karachunski PI, Day JW, McDonald CM, Darras BT, Kang PB, Siener CA, Gadeken RK, Anand P, Schierbecker JR, Malkus EC, Lowes LP, Alfano LN, Johnson L, Nicorici A, Kelecic JM, Quigley J, Pasternak AE, Miller JP; MDA-DMD Clinical Research Network. Clinical trial readiness in non-ambulatory boys and men with duchenne muscular dystrophy: MDA-DMD network follow-up. Muscle Nerve. 2016 Oct;54(4):681-9.
 
Jeppesen J, Green A, Steffensen BF, Rahbek J. The Duchenne muscular dystrophy population in Denmark, 1977-2001: prevalence, incidence and survival in relation to the introduction of ventilator use. Neuromuscul Disord. 2003 Dec;13(10):804-12.
 
Lyager S, Steffensen B, Juhl B. Indicators of need for mechanical ventilation in Duchenne muscular dystrophy and spinal muscular atrophy. Chest. 1995 Sep;108(3):779-85.
 
Mayhew AG, Eagle M, Steffenson B. 17th International Congress of The World Muscle Society: S.P.6 Exploratory Rasch analysis of the EK2 scale used in a population of Duchenne muscular dystrophy (DMD). Neuromuscul Disord. 2012:22(9-10);877.
 
Rahbek J, Werge B, Madsen A, Marquardt J, Steffensen BF, Jeppesen J. Adult life with Duchenne muscular dystrophy: observations among an emerging and unforeseen patient population. Pediatr Rehabil. 2005 Jan-Mar;8(1):17-28.
 
Rehabiliterings Center for Muskelsvind. EK scale. Available at: https://rcfm.dk/ek-skalaen-ek-scale/. Accessed on 20 September 2023.
 
Werlauff U, Fynbo Steffensen B. The applicability of four clinical methods to evaluate arm and hand function in all stages of spinal muscular atrophy type II. Disabil Rehabil. 2014;36(25):2120-6.
 
Werlauff U, Vissing J, Steffensen BF. Change in muscle strength over time in spinal muscular atrophy types II and III. A long-term follow-up study. Neuromuscul Disord. 2012 Dec;22(12):1069-74.
 
Document last updated October 2024