RESEARCH ARTICLE

Hand Exercise Intervention in Patients with Polymyositis and Dermatomyositis: A Pilot Study Malin Regardt1,2*, Marie-Louise Schult3,4, Yvonne Axelsson1, Anna Aldehag2, Helene Alexanderson2,5, Ingrid E. Lundberg6 & Elisabet Welin Henriksson2,6 1

Department of Occupational Therapy, Karolinska University Hospital, Solna, Sweden

2

Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden

3

Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden

4

Rehabilitation Medicine University Clinic, Danderyd Hospital, Stockholm, Sweden

5

Department of Physical Therapy, Karolinska University Hospital, Solna, Sweden

6

Rheumatology Unit, Karolinska University Hospital, Stockholm, Sweden

Abstract Objective. The aim of the present study was to develop a 12-week hand exercise intervention for patients with polymyositis (PM) and dermatomyositis (DM) and evaluate adherence, patients’ opinions of the programme design and overall feasibility, and the effect on hand function and activity limitation after the intervention. Method. A pilot hand exercise intervention was conducted on a convenience sample of 15 patients with reduced handgrip strength and established, inactive PM and DM. Acceptable adherence was set at 75%. The programme was evaluated based on patients’ opinions regarding exertion, the movements involved and overall feasibility. Hand- and pinch-grip strength, grip ability, dexterity and activity limitation were assessed. Results. Eleven of 15 patients completed the intervention, with acceptable adherence of 78–100%. Measures of handgrip strength, dexterity and activity limitation were reduced at baseline compared with normative data from the literature. Throughout the intervention, rates of perceived exertion were scored between ‘moderate’ and ‘fairly strong’. Finger abduction and adduction were excluded from the hand exercise programme because they were not feasible to perform. Repetitions of the exercise increased gradually to a maximum of 30 per movement. Patients regarded this as too time-consuming and suggested ten repetitions daily or 10–20 repetitions 2–4 times per week. There were some individual, clinically meaningful improvements in hand function and activity limitation. A comparison between baseline and after the intervention showed that the three-jaw (tripod) pinch-grip strength (left hand) had increased (p < 0.007; z = –2.7). Conclusion. A hand exercise programme was found to be feasible to perform by patients with established PM or DM. The effect was limited, with few individual improvements in hand function and activity limitation, indicating a need to increase the resistance in the movements and to limit the duration of each exercise session. Copyright © 2014 John Wiley & Sons, Ltd. Keywords hand exercise; occupational therapy; polymyositis; dermatomyositis; activity limitation *Correspondence Malin Regardt, Department of Occupational Therapy, Karolinska University Hospital, Solna, S-171 76 Stockholm, Sweden. Tel: +46 70 4095783; Fax: +46 8 517 730 80. Email: [email protected]

Published online 12 March 2014 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/msc.1069

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Introduction Polymyositis (PM) and dermatomyositis (DM) are rare, idiopathic inflammatory myopathies characterized by weakness and low endurance of skeletal muscles (Dorph and Lundberg, 2002). Treatment of PM and DM is based on glucocorticoids, immunosuppressive drugs and physical exercise (Alexanderson, 2012; Alexanderson and Lundberg, 2012; Marie and Mouthon, 2011). Despite treatment, approximately 80% of patients perceive reduced muscle function, disability and low health-related quality of life (HRQoL) (Bronner et al., 2006). Reduced muscle function is commonly reported in the proximal muscles (Harris-Love et al., 2009). However, authors have previously reported that grip force was reduced in patients with PM and DM; men had approximately 60% of the grip force expected for gender- and agematched normative values in the literature, and women had approximately 71% (Regardt et al., 2011). In patients with PM and DM, reduced grip force was found to be associated with activity limitation in domestic activities, and in women with low HRQoL (Regardt et al., 2011). The same study also reported that patients with PM and DM had only minor limitations in joint mobility (Regardt et al., 2011). According to our clinical experience, other aspects of hand function, such as dexterity and grip ability, may also be affected in patients with PM and DM as they have been reported to drop lightweight objects, such as envelopes. In general, hand function is important in many occupational tasks and includes the ability to move the hands and fingers and having the strength and endurance to perform daily activities over prolonged periods (Flinn et al., 2008). Occupational therapists often use hand exercises as treatment in clinical practice, and studies have indicated improvement in hand function in patients with rheumatic or muscle-affecting diseases (Aldehag et al., 2013; Brorsson et al., 2009; Buljina et al., 2001; Hammond, 2010a; Ronningen and Kjeken, 2008; Wessel, 2004; Youngstrom, 2002). These hand exercise studies usually include movements to enhance range of motion (ROM) and/or hand strength (Hammond, 2010b; Rogers and Wilder, 2009; Wessel, 2004). As PM and DM patients have reduced grip force and only minor limitation in joint mobility, movements to enhance ROM may not be considered as necessary in a hand exercise intervention (Regardt et al., 2011). An effective prescription (number of repetitions and frequency) for hand exercises to improve hand function has not yet been established (Heine et al., 2012). Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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In general, to enhance strength and endurance, the American College of Sports Medicine (ACSM) recommends exercise 2–3 days per week, with every movement repeated 8–12 times (Garber et al., 2011). To enhance muscle strength and endurance over the exercise period, resistance, frequency or duration must be increased (the progressive overload principle) (Garber et al., 2011). The Rating of Perceived Exertion (RPE) Borg Category Ratio (CR) 10 scale (Borg, 1982, 1990) has been used to regulate the intensity/resistance of a hand exercise programme in patients with rheumatoid arthritis (RA) (Heine et al., 2012), and this rating has been shown to correlate with grip force (Li and Yu, 2011). To our knowledge, no study has investigated whether patients with PM and DM who have reduced handgrip strength can benefit from a hand exercise programme. The International Myositis Assessment and Clinical Studies (IMACS) group is involved in developing consensus on outcome measures and improvement of myositis diseases (Rider et al., 2003). A minimum of 15% improvement in muscle strength and physical function is considered clinically meaningful for patients with PM and DM (Rider et al., 2003). The IMACS group is also involved in establishing a core set of measures to evaluate disease activity (Lachenbruch et al., 2007). The six-item core set includes both assessments evaluated by the physician {physician global assessment of disease activity rated on a visual analogue scale [VAS], muscle strength [manual muscle test in eight muscle groups (MMT-8)] and extra-muscular activity [using a VAS]} and self-rated measures by the patients {patients’ global assessment of health [using a VAS], physical functioning [Health Assessment Questionnaire (HAQ)]}, alongside laboratory measures {muscle enzymes [creatine kinase (CK)]}(Lachenbruch et al., 2007). The objective of the present pilot study was to develop a hand exercise programme for patients with impaired hand function. Therefore, we aimed to evaluate adherence, patients’ opinions on programme design and overall feasibility, and the effect on hand function and activity limitation in a 12-week hand exercise intervention for patients with PM and DM.

Methods Subjects The hand exercise intervention was introduced to a convenience sample of 15 patients with PM (n = 7) or DM (n = 8) [probable or definite, according to Bohan 161

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and Peter criteria (Bohan and Peter, 1975)] who were recruited from and consulted at the rheumatology clinic at Karolinska University Hospital in Stockholm and who had (a) reduced handgrip strength when compared with gender- and age-matched normative data from the literature (Nordenskiold and Grimby, 1993) (according to patient records), (b) established disease (> 6 months) and (c) low disease activity (with conventional immunosuppressive treatment according to the choice of the treating physician). The sample included nine women and six men, with a mean age of 62 (± 14.4) years and mean disease duration of 7.4 (± 6.5) years.

Procedures Before and after the 12-week hand exercise intervention, patients were assessed by a physician for disease activity [according to the IMACS six-item core set (Lachenbruch et al., 2007)], an occupational therapist (third author) evaluated hand function [Jamar dynamometer, pinch meter, Grip Ability Test (GAT), Purdue Pegboard Test (Buddenberg and Davis, 2000)], and for activity limitation by using the Disability of the Arm, Shoulder and Hand (DASH) questionnaire (Figure 1) (Dixon

et al., 2008; Hunsaker et al., 2002). The hand exercise programme was introduced by a second occupational therapist (first author). The occupational therapist observed the patients performing the exercise, to ensure that they were able to follow the programme and had understood how the exercises should be performed. Patients were given the option of exercising at the hospital once a week and follow-up visits were carried out throughout the study by telephone, at the hospital or both, and were planned jointly by the patient and occupational therapist (first author). At the follow-up visits, the occupational therapist checked the exercises again to make sure that the programme was performed correctly. Patients were asked not to change their lifestyle or start any other form of exercise during the study period, and this was confirmed at the end of the study.

Hand exercise intervention There is limited knowledge about how hand function is affected in patients with PM and DM. Therefore, a general programme was designed using a variety of handstrengthening movements intended to improve hand functions involved in accomplishing daily activities

Figure 1. Procedure for the hand exercise intervention and the hand exercise programme. Two sets of movements were performed at every § exercise session (three times per week for 12 weeks) Five repetitions performed during weeks 1–4, ten repetitions performed during weeks §§ 5–8 and 15 repetitions performed during weeks 9–12. Ten repetitions performed during weeks 1–4, 20 repetitions performed during weeks 5–8 and 30 repetitions performed during weeks 9–12.

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(Flinn et al., 2008). This programme was based on hand and finger movements using personally adapted resistance putties (standardized doughs) {Royal putty [medium, light or x-lite (Mediroyal Nordic AB©, Stockholm, Sweden)] and Jura putty [medium soft (JURA Medical©, Glasgow, United Kingdom)]}. The putties were tested so that each patient could fully flex his or her fingers through the dough (Garber et al., 2011) and the patients were asked to evaluate subjectively whether the putty was ‘too soft’, ‘too hard’ or ‘just right’. If the dough was too hard or too soft, it was changed to another with more or less resistance or was mixed until it felt ‘just right’. When the patient could flex his or her fingers through the dough and it felt ‘just right’, he or she was asked to rate exertion on one of the movements in the programme [finger flexion, 30 repetitions (Figure 1)] using the RPE Borg CR 10 scale of exertion (Borg, 1982, 1990). The occupational therapist (first author) chose the putties based on a lower limit on the RPE Borg CR 10 scale, ‘moderate exertion’ (≥ 3) (Borg, 1982, 1990). The mean rating on the scale was ‘strong exertion’ 5 (± 1.8), with the range being from 3 (‘moderate’) to 8 (‘more than strong exertion’). The hand exercise programme was aimed to be performed three times a week for 12 weeks (in total, 36 times) and was illustrated by pictures from the Mobilus Professionals program (Mobilus Digital Rehab AB Sweden©, Gothenburg, Sweden). To meet the possible improvement in strength, the number of repetitions increased every fifth week (Garber et al., 2011). Figure 1 provides further information about the hand exercise programme, the various movements and the number of repetitions performed throughout the intervention. Patients kept diaries of their exercise, documenting each session performed, their ratings on the RPE Borg CR 10 scale (Borg, 1982, 1990) and any comments they had about the programme.

Measures Adherence and design of hand exercise programme Adherence was defined as the completed number of exercise sessions performed compared with the expected number (36). This information was collected from patients’ exercise diaries. An acceptable adherence was ≥75% (≥ 27 repetitions). The hand exercise programme was evaluated based on patients’ exertion rating using the RPE Borg CR Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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10 scale after every session (Borg, 1982, 1990). In addition, patients were asked their opinions about the programme, the frequency and the overall feasibility of undertaking the hand exercises. Outcome measures Outcome measures were evaluated by (a) comparing the patients’ results with normative values from the literature if they were affected at baseline (when applicable) and (b) changes between baseline and follow-up. Hand function: In total, all of the following assessments of hand function took approximately 30 minutes to perform. Hand grip strength was measured in the right and left hands separately using a computer-connected Jamar dynamometer (kg) (Biometrics E-link H 500 hand kit, Newport, United Kingdom) (Massy-Westropp et al., 2004). The occupational therapist (third author) told patients, and also demonstrated how, to squeeze three times, as hard as they could, first in the right hand and then the left hand. There were only a few seconds of rest between every attempt. In the analysis, the average of the three measures for each hand was used. Normative data from a population-based study for women and men in different age groups are available for comparison (Massy-Westropp et al., 2004). A minimal significant change of at least 6 kg indicates a clinically meaningful improvement in hand grip strength measured by the Jamar instrument (Roberts et al., 2011). Pinch-grip strength was measured in the right and left hand separately by a computer-connected Biometrics pinch meter (kg) (Biometrics E-link H 500 hand kit, Newport, United Kingdom, which is designed with a thinner profile than a regular pinch gauge meter) in three positions: key (lateral), three-jaw (tri-pod) and thumb to index finger opposition (tip-to-tip). Three attempts were performed in each position, and the average value per position for each hand was used in the analysis. The literature contains no comparable normative values or guidelines on what could be considered a clinical improvement in this measure. Therefore, the study used the definition suggested by the IMACS group: ≥ 15% increase for a clinically meaningful improvement in muscle strength and physical function (Rider et al., 2003). Grip ability was measured using the GAT (Dellhag and Bjelle, 1995), which includes three grips that patients perform, with a faster time meaning a better score and better grip ability. The three grips include putting a sock 163

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over the non-dominant hand, putting a paperclip on an envelope and pouring water from a 1-litre jug into a cup. In the literature, the average mean value in healthy controls is 16.5 seconds, and a value < 20 is regarded as normal grip ability (Dellhag and Bjelle, 1995; Poole, 2011). To our knowledge, there are no guidelines on what is considered a clinically meaningful improvement in GAT. Therefore, the present study also used the definition suggested by the IMACS group for a clinically meaningful improvement in muscle strength and physical function, as previously discussed, (≥ 15%) (Rider et al., 2003). Dexterity was measured by the Purdue Pegboard Test (Buddenberg and Davis, 2000), which includes two parts. In the first part, patients put as many pegs as possible on a board containing 25 holes, using one hand at a time, for 30 seconds. In the other part, patients have 60 seconds to manipulate pegs, collars and washers (assembly) onto the board. The number of pegs, collars and washers that the patient places on the board is calculated; the higher the number achieved, the better the dexterity they possess (Buddenberg and Davis, 2000). The test was done three times, with no more than 15 seconds of rest between the attempts, and the average of the three trials was used in the analysis. For comparison, the literature contains normative values based on a convenience sample (Buddenberg and Davis, 2000). A repeatability test has been conducted on other muscle-affecting diseases (e.g. muscular dystrophy), suggesting a true difference of two or three pegs between attempts (Aldehag et al., 2008). Based on these results, a difference of ≥ 3 was considered to be a clinically meaningful improvement. Activity limitation: Activity limitation was measured using the DASH questionnaire (Dixon et al., 2008; Hunsaker et al., 2002). This is a 30-item questionnaire designed to measure physical function and symptoms in people with any or several musculoskeletal disorders of the upper limbs. Patients self-rated their ability on a fivepoint scale ranging from no difficulty (1) to impossible to do (5). Scores were calculated ranging from 0–100, with a higher score indicating greater activity limitation. The results were compared with published normative values from the general population (Hunsaker et al., 2002). A minimal change of at least 10 points was considered to be a clinically meaningful improvement (Gummesson et al., 2003). Data analysis Patient characteristics, adherence, disease activity, medical treatment, measures of hand function (handgrip 164

strength, pinch-grip strength, grip ability and dexterity) and activity limitation are presented as numbers, percentages, means, standard deviations, medians (md) and interquartile ranges (IQR). The Wilcoxon Signed Rank test was used to analyse differences at baseline between patients with PM or DM and normative values from the general population or healthy individuals from the literature regarding handgrip strength (Jamar dynamometer) (Massy-Westropp et al., 2004), grip ability (GAT) (Dellhag and Bjelle, 1995), dexterity (Purdue Pegboard Test) (Buddenberg and Davis, 2000) and activity limitation (DASH) (Hunsaker et al., 2002) (null hypothesis = no difference between PM and DM distribution and normative values). The observed values for patients with PM and DM were standardized using gender- and age-specific normative values from the general population or healthy individuals (mean and standard deviation) from the literature (Buddenberg and Davis, 2000; Dellhag and Bjelle, 1995; Hunsaker et al., 2002; Massy-Westropp et al., 2004). The Wilcoxon Signed Rank Test was used to analyse differences between baseline and follow-up in hand function (handgrip strength, pinch-grip strength, grip ability and dexterity), activity limitation, disease activity and medical treatment. Effect size was used to evaluate the responsiveness, defining values from 0.2–0.5 as a low level of responsiveness, from 0.51–0.8 as moderate and >0.81 as a high level of responsiveness (Roberts et al., 2011). Individual differences between baseline and followup were described and meaningful change was evaluated based on respective measures; if this was not applicable, the IMACS group-suggested definition of clinically meaningful improvement in muscle strength and physical function (≥ 15%) was used (Rider et al., 2003). The significance level for all analyses was ≤0.05. All statistical calculations were made using the IBM Statistical Package for the Social Sciences (SPSS) version 19 (Armonk, NY, USA).

Ethical approval Participants gave written informed consent to participate, according to the Declaration of Helsinki (World Medical Association, 2013), and the study was approved by the regional ethical review board in Stockholm, Sweden in 2005. Additional applications regarding measurements and design were approved in 2010 and 2012. Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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Results Participant demographics Eleven of the 15 participants who were recruited completed the intervention (five women and six men), with a mean age of 63 (± 12) years and mean disease duration of 8 (± 7) years (Table 1). Four participants did not complete the intervention owing to either unstable disease or reduced well-being (n = 3), or for an unknown reason (n = 1). Two of the participants were left-hand dominant (participants 3 and 10). At baseline, handgrip strength was reduced by approximately 32% in the right hand and 30% in the left, compared with gender- and age- matched normative values based on the general population in the literature (Massy-Westropp et al., 2004). Measures of disease activity according to the IMACS group six-item core set, including evaluations by the physician, self-rated measures by the participants, and laboratory measures (Lachenbruch et al., 2007), remained unchanged between baseline and follow-up (see Table 1).

Adherence and feasibility of hand exercise programme design Participants who completed the intervention performed the exercise programme between 28 and 36 times (78–100%), regardless of whether the exercises were done at the hospital or at home, showing an adherence

rate of more than 75%, which was considered acceptable (Table 2). As the hand exercise programme included an increased number of repetitions every fifth week, the approximate time to perform the programme was 20–60 minutes, depending on how many repetitions were done and how fast the participants performed the movements. This information was documented at the follow-ups performed at the hospital. The diaries of ten of the 11 participants reported exertion on the PRE Borg CR 10 scale for an average of 32 of the 36 sessions. When the number of repetitions increased, the exertion rating did not change significantly. The median exertion value for the first four weeks (weeks 1–4) was ‘moderate exertion’ [md 3 (IQR 3–4)], and during weeks 5–8 [md 4 (IQR 3–5)] and weeks 9–12 [md 4 (IQR 3–4)] was ‘fairly strong exertion’. After completing the intervention, participants were asked to suggest a feasible number of repetitions and also how many sessions per week would have been appropriate for their lifestyles. All participants thought that 30 repetitions were too many, as they took too long to perform. Suggestions varied from ten repetitions every day to 10–20 repetitions in 2–4 sessions per week. Regarding the various movements, the first four participants described, in their diaries and at follow-ups, difficulties in performing finger abduction and finger

Table 1. Patient characteristics and differences in disease activity and medical treatment between baseline and follow-up Patient characteristics

Total group (n = 11)

Diagnosis PM, n (%) Gender (women), n (%) Age (years), mean (SD) Disease duration (years), mean (SD) Right-hand dominance, n (%) Disease activity PGA (VAS), mean (SD) Patients’ global assessment (VAS), mean (SD) MMT-8 (0–80), mean (SD) Extramuscular VAS (0–100), mean (SD) HAQ (0–3), mean (SD) CK, mean (SD) Prednisolone, n (%) Daily dosage (mg), median (IQR) DMARD, n (%)

5 (46) 6 (55) 63 (12) 8(7) 9 (82) Baseline 16 (9) 34 (25) 76 (4) 12 (9) 0.9 (0.5) 2.9 (3.3) 9 (82) 5 (1.3–7.5) 5 (46)

Follow-up 19 (13) 52 (28) 75 (5) 20 (18) 0.9 (0.6) 2.6 (2.1) 7 (73) 5 (0–7.5) 7 (64)

p-value ns ns ns ns ns ns ns ns ns

CK, creatine kinase; DMARD, disease-modifying antirheumatic drug; HAQ, Health Assessment Questionnaire; IQR, interquartile range; MMT-8, manual muscle test in eight muscle groups; ns, not significant; PGA, physician global assessment of disease activity; PM, polymyositis; SD, standard deviation; VAS, visual analogue scale (0–100).

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Table 2. Measures of adherence as a total and based on exercise location and measures of exertion at baseline and at different time points in the hand exercise intervention Adherence (0-36) Patient ID 1 2 3† 4 5 6 7 8 9 10† 11

PRE Borg CR 10 scale (0–10)

Total exercise sessions n

Exercise sessions at the hospital n

Exercise sessions at home n

Baseline

31 36 33 34 34 30 28 36 36 35 31

0 0 1 1 5 7 1 5 3 1 1

31 36 32 33 29 23 27 31 33 34 30

5 5 8 7 7 5 3 4 3 7 3

Weeks 1–4 median (IQR) 5 (4.8–5.3) 3 (3–3) 6 (6–7) 5 (4–5) 3 (3–3) 4 (3–4) 3 (3–4) 2.5 (2–3) 3 (2–5.5) 3 (2.3–4)

Weeks 5–8 median (IQR)

Weeks 9–12 median (IQR)

5 (4–5) 3 (3–3) 6 (6–6) 5 (4–7) 3 (2.8–4) 1 (0–1.3) No reported measures 4 (3.3–4) 4 (3.3–4) 2 (2–3) 4 (3–4)

5 (4.3–5.8) 3 (3–3) 6 (6–6) 4 (4–5) 3 (2–3) 0 (0–0.5) 3 (3–4) 4 (4–4) 3 (2-3.8) 4 (3–4)

CR, category ratio; ID, identification; IQR, interquartile range; RPE, rating of perceived exertion. †

Left-hand dominance.

adduction (Figure 1). They described managing the putty as being a motor challenge rather than a muscular one and said that it was difficult to get sufficient resistance from the putty. Therefore, these two movements were excluded from the programme for the rest of the participants (n = 7).

Outcome measures Hand function Handgrip strength: At baseline, handgrip strength was reduced compared with gender- and age-matched normative values based on the general population in the literature (Massy-Westropp et al., 2004) (p < 0.001). Seven participants increased handgrip strength in the right hand by, 1.1–8.8 kg (7.3–69.0%), and six participants increased handgrip strength in the left hand by, 1.4–12.2 kg (8.6–109.6%) (Table 3). Two participants had a clinically meaningful improvement of more than 6 kg: Participant 3 (both hands) and Participant 8 (left hand). However, as a group, handgrip strength did not improve significantly (right hand: p = 0.07; left hand: p = 0.09) by the end of 12-week intervention. Pinch-grip strength: Pinch-grip strength, both at baseline and follow-up, varied between 3 and 5 kg in the three positions (Table 4), although none was statistically significantly improved, apart from the three-jaw (tripod) grip in the left hand. Key pinch-grip strength 166

in the right hand increased in four participants by 0.1 and 1.0 kg (8.3–15.4%) and in one of these (Participant 7), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003). Three participants had a clinically meaningful improvement in key pinch-grip strength in the left hand by, 0.4–1.2 kg (18.2–26.6%) (Participant 3, 8 and 11) (Rider et al., 2003) (Table 3). Three-jaw pinch strength in the right hand increased in seven participants by 0.6–2.6 kg (7.0–208.1%) and in five of these (Participants 2, 3, 4, 6 and 9), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003) (Table 3). Nine participants increased three-jaw pinch strength in the left hand by 0.2–2.7 kg (6.0–192.9%) and in five of these (Participants 3, 4, 6, 8 and 10), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003) (Table 3). The thumb to index finger pinch strength in the right hand increased in seven participants by 0.1–1.2 kg (2.8– 233.3%) and in four of these (Participants 3, 4, 6 and 10), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003). In the left hand, the thumb to index finger pinch strength increased in eight participants by 0.1–1.2 kg (6.7–50.0%) and in six of these (Participants 1, 3, 4, 6, 7 and 10), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003) (Table 3). As a group, the three-jaw pinch-grip strength in the left hand improved significantly after the hand exercise Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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Table 3. Measures of a 12-week hand exercise intervention at baseline and follow-up

Handgrip strength (kg)

Key pinch-grip strength (kg)

Three-jaw pinchgrip strength (kg)

Thumb to index finger pinch-grip strength (kg)

Patient ID

Baseline right/left

Follow-up right/left

Baseline right/left

Follow-up right/left

Baseline right/left

Follow-up right/left

Baseline right/left

Follow-up right/left

1 2 3† 4 5 6 7 8 9 10† 11

18.9/16.3 31.6/34.8 12.8/11.2 16.7/14.3 26.7/22.3 14.5/16.4 27.9/26.5 21.3/20.6 21.1/15.4 12.1/18.8 22.1/17.0

20.7/17.7 31.6/34.8 21.6/23.4 19.1/16.7 26.7/22.3 15.6/14.5 31.6/29.7 24.5/27.7 19.9/20.1 15.2/18.7 19.5/15.4

4.0/5.3 9.3/8.9 3.9/3.1 4.2/2.4 8.4/7.2 2.7/3.6 6.5/7.4 6.1/6.1 3.6/2.6 1.2/2.6 2.6/2.2

3.6/5.1 6.9/7.7 4.3/4.0 4.2/2.4 8.4/7.1 2.0/2.2 7.5/7.4 6.8/7.3 2.5/2.5 1.3/2.4 2.6/2.6

6.5/6.1 8.1/8.3 3.2/3.0 2.8/1.4 4.8/5.4 1.2/1.5 8.6/9.1 6.2/6.2 3.0/2.3 3.6/2.0 3.1/2.2

5.1/6.5 10.2/8.8 3.9/4.3 4.2/4.1 4.8/5.4 3.8/2.5 9.2/10.2 6.9/7.3 3.6/2.5 2.3/2.3 2.1/2.2

4.2/3.4 4.8/5.6 1.8/2.4 1.8/1.5 3.2/3.6 0.8/1.3 4.4/4.0 3.1/5.5 2.6/1.5 0.3/1.2 1.5/1.7

4.4/4.4 4.9/6.0 3.1/3.6 2.6/2.2 3.2/3.6 2.0/1.5 4.9/5.2 2.4/3.4 1.8/1.6 1.0/1.4 1.5/1.4

ID, identification. Values in bold indicate clinically meaningful improvement, according to definition of measurement or the International Myositis Assessment and Clinical Studies (IMACS) group (Rider et al., 2003; Roberts et al., 2011). †

Left-hand dominance.

Table 4. Handgrip strength, pinch-grip strength, grip ability, dexterity and activity limitation in the total group at baseline and 12-week follow-up, and significant difference between baseline and follow-up Total (n = 11) Measure Handgrip strength (kg) Right Left Pinch-grip strength (kg) Key, right Key, left Three-jaw, right Three-jaw, left Thumb to index finger, right Thumb to index finger, left GAT (seconds) Purdue Pegboard Test (n) Dexterity, right Dexterity, left Assembly DASH (0–100)

Baseline

Follow-up

p-value

Median (IQR) 21.1 (14.5–26.7) 17.0 (15.4–22.3)

Median (IQR) 20.7 (19.1–26.7) 20.1 (16.7–27.7)

0.07 0.09

4.0 (2.7–76.5) 3.6 (2.6–7.2) 3.6 (3.0–6.5) 3.0 (2–6.2.0) 2.6 (1.5–4.2) 2.4 (1.5–4.0) 17.8 (13.5–20.3)

4.2 (2.5–6.9) 4.0 (2.4–7.3) 4.2 (3.6–6.9) 4.3 (2.5–7.3) 2.6 (1.8–4.4) 3.4 (1.5–4.4) 15.4 (13.0–20.1)

0.77 0.59 0.31 0.007 0.13 0.15 0.51

13.0 12.3 23.3 30.2

12.7 13.3 28.0 40.0

0.09 0.17 0.96 0.82

(12.3–14.3) (10.3–14.0) (21.3–30.7) (13.3–50.8)

(11.3–15.0) (11.7–13.7) (21.7–31.0) (16.7–50.8)

DASH, Disability in Arm, Shoulder and Hand; GAT, Grip Ability Test IQR, interquartile range Values in bold indicate a statistical significant improvement.

intervention (p = 0.007) (Table 3). The effect size revealed a level of responsiveness of 0.3, which, according to Roberts et al. (2011), was low. No other significant changes were found regarding pinch-grip strength. Grip ability: There was no difference in participants’ grip ability at baseline (p = 0.33), as measured by GAT, compared with that of healthy individuals from the literature (Dellhag and Bjelle, 1995). Six Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

participants improved after the intervention, by 1.2–5.6 (8.9–29.5%) and in three of these (Participants 1, 6 and 9), the improvement could be considered clinically meaningful (≥ 15%) (Rider et al., 2003) (Table 5). As a group, grip ability did not improve significantly (p = 0.51) after the intervention. Dexterity: At baseline, participants with PM and DM had reduced dexterity, as measured by both parts 167

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Table 5. Measures of a 12-week hand exercise intervention at baseline and follow-up Purdue Pegboard Test (n) GAT (s) Patient ID 1 2 3† 4 5 6 7 8 9 10† 11

Dexterity

Assembly

DASH score

Baseline

Follow-up

Baseline right/left

Follow-up right/left

Baseline

Follow-up

Baseline

Follow-up

21.9 11.5 13.3 20.3 20.1 16.8 13.5 23.6 18.9 17.8 15.3

17.9 12.0 12.1 18.3 20.1 13.0 15.4 29.2 13.3 20.5 14.0

12.3/10.3 17.3/15.0 13.0/14.3 10.0/9.0 13.7/13.3 13.0/11.0 14.3/13.3 12.0/10.3 13.3/11.7 13.0/12.3 15.0/14.0

11.0/10.7 16.7/14.7 12.0/13.3 10.7/9.7 13.7/13.3 12.7/11.7 15.0/13.7 11.3/11.7 11.7/12.7 13.0/14.3 15.0/13.7

22.0 45.7 28.7 18.0 28.7 21.0 30.7 21.3 22.3 23.3 48.3

21.7 42.3 31.0 19.0 28.7 20.3 30.3 24.7 28.0 22.3 41.0

2.5 13.3 50.8 24.2 84.2 30.2 0.0 42.2 19.6 52.6 43.3

1.7 29.2 40.0 25.0 50.8 50.0 0.8 51.7 16.7 49.0 51.7

DASH, Disability in Arm Shoulder and Hand; GAT, Grip Ability Test Values in bold indicate clinically meaningful improvement according to definition of the measurement or the International Myositis Assessment and Clinical Studies (IMACS) group (Aldehag et al., 2008; Gummesson et al., 2003; Rider et al., 2003). †

Left-hand dominance.

of the Purdue Pegboard Test, compared with normative values from the literature (Buddenberg and Davis, 2000) (p < 0.001). Three participants had increased dexterity in the left hand by a score of 1.0–2.0 (8.6–16.2%) (Table 5). Dexterity in the assembly task increased in four participants by a score of 1.0–5.7 (5.6–25.4%) and in two of these (Participants 8 and 9), the improvement could be considered clinically meaningful (n ≥ 3) (Aldehag et al., 2008) (Table 5). At the group level, dexterity did not improve significantly after the intervention. Activity limitation At baseline, participants had more limitation of their activity, as measured by DASH, compared with normative values based on the general population from the literature (Hunsaker et al., 2002) (p = 0.012). Five participants improved by a score of 0.8–33.3 (6.8–39.6%) (Table 5) and in two of these (Participants 3 and 5), the improvement could be considered clinically significant (≥ 10 points) (Gummesson et al., 2003). At the group level, the activity limitation remained unchanged from baseline to follow-up (p = 0.82) (Table 4).

Discussion In the present pilot study, we demonstrated that the hand exercise programme could be considered feasible to perform for patients with established inactive PM 168

and DM. The intervention had good adherence, and, in various tests, a trend towards improvement was recorded for some patients, although this was statistically significant only for the group in the three-jaw pinch-grip strength test in the left hand. Participants in the study had reduced handgrip strength, dexterity and activity performance compared with normative data, indicating that these measures may be valuable as outcome measures in a hand exercise intervention. Feasibility, adherence and relevant outcome measures are important for designing a new therapeutic intervention. Studies show that supervision improves compliance during exercise (Voet et al., 2010). Participants completing the intervention had an average of four follow-ups, either by telephone or hospital visit. Adherence was considered good as all participants who completed the study undertook more than 75% of the intended sessions. This might have been because patients who agree to participate in an exercise study are probably motivated to undertake the intervention and inclined to persevere. In fact, behavioural theory notes that patients participating in an intervention are more likely to perform it if they perceive it as beneficial (Serfass and Gerberich, 1984). Thus, a person would be more motivated to take part in a hand exercise programme if they perceived that they had reduced hand function. At baseline, all participants had reduced handgrip strength, but the current study did not address whether or not this reduced handgrip strength Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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was perceived by patients as reduced or affected their ability to perform daily activities. However, studies of other rheumatic diseases have found associations between reduced handgrip strength and the ability to perform daily activities (Nordenskiold, 1997; Sandqvist et al., 2004; Shipham and Pitout, 2003). In addition, positive effects on adherence have been shown by using an exercise diary in home exercise programmes (Moseley, 2006). Another aspect that could influence adherence is the number of movements prescribed. A study of home-based exercise in patients with neck and lower-back pain found that having six or more movements predicted low adherence to the programme, whereas three or fewer movements predicted good adherence (Medina-Mirapeix et al., 2009). However, the number of movements in the current study, between six and eight, did not seem to influence adherence. Another important aspect of adherence and motivation is whether the patient has goals that are specific, measureable, attainable, realistic and timely (Heine et al., 2012). This aspect was not applied in the current study and should be considered in future hand intervention studies. Hand function was assessed by handgrip- and pinchgrip strength, grip ability and dexterity. These measures were chosen because they have been shown to be important aspects of hand function (Prosser and Bruce, 2003). For some of the measurements [hand grip strength (Jamar dynamometer), grip ability (GAT) and dexterity (Purdue Pegboard Test)], there are published normative values from the general population enabling comparisons to be made with population norms (Buddenberg and Davis, 2000; Dellhag and Bjelle, 1995; Massy-Westropp et al., 2004). Although there are no available normative values for the E-link pinch meter used in the present study, there are normative values on another measure of pinch-grip strength, the pinch gauge meter (Werle et al., 2009). Normative values obtained using the pinch gauge meter vary from 4.5–10.3 kg, depending on age, gender and hand dominance (Werle et al., 2009), indicating that the pinch-grip strength of some patients with PM and DM (3–5 kg) might be in the lower range. At baseline, Jamar dynamometry, Purdue Pegboard and DASH measures were reduced compared with normative values, and these measures were able to detect individual changes in patients with PM and DM. Therefore, these measures might be considered for inclusion in other hand exercise interventions. In Musculoskelet. Care 12 (2014) 160–172 © 2014 John Wiley & Sons, Ltd.

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addition, the pinch meter was able to detect individual changes, and might also be important to include. However, participants demonstrated no grip ability limitations, as measured by GAT (Dellhag and Bjelle, 1995), which might have been because of ceiling effects of the instrument, suggesting that GAT might not be appropriate to use in patients with PM and DM. The RPE Borg CR 10 scale was used to evaluate the resistance of the dough before and throughout the intervention. This scale has been used in a variety of settings and has shown correlations with heart rate using a cycle ergometer but also associations with various amounts of grip force and with muscle activation. These studies indicate that the RPE Borg CR 10 scale may be suitable measure for determining the amount of resistance needed to improve hand function in a hand exercise intervention (Andersen et al., 2010; Borg, 1982, 1990). Scale ratings on exertion did not vary much throughout the intervention. In a large, controlled exercise intervention in patients with RA, Heine et al. (2012) recommended an initial rating between 3 (‘moderate exertion’) and 4 (‘fairly strong exertion’) on the RPE Borg CR 10 scale to enable progression and reduce the risk of overload. In that study (Heine et al., 2012), the measurement of exertion was performed after completing the whole exercise programme, whereas in the present study exertion was rated on only one of the movements (30 repetitions of finger flexion). In the current study, one participant (Participant 3) had increased values in seven out of eight measures. This participant had higher initial ratings on the RPE Borg CR scale compared with the other participants, indicating that the other participants might have been working with putties that did not give sufficient resistance to increase strength and endurance. Because there is limited knowledge on hand function in patients with PM and DM, the hand exercise programme used in the current study contained a variety of hand-contracting movements that are used in daily activities (Flinn et al., 2008). The current study did not include any ROM movements because an earlier study had shown that patients with PM and DM had only minor mobility limitations (Regardt et al., 2011). A recent report indicated that arthritis in the wrist and finger joints (metacarpophalangeal and proximal interphalangeal joints) is more common in patients with inflammatory myopathies than previously described (≈20%) (Klein et al., 2013). Arthritis in the hands is known to lead to deformities, dysfunction 169

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and reduced ROM (Heine et al., 2012; Waljee et al., 2010). In the current study, PM and DM patients with arthritis or other comorbid diseases that could affect the hand were excluded. The hand exercise programme used in the present study aimed to include functional grips and muscles involved in flexion and extension. After the first four participants had completed the intervention, they reported that performing finger abduction and adduction caused more of a motor than a muscular challenge. It became apparent that it was not meaningful to continue with these movements, so, as this was a pilot study, these movements were removed from the programme. Increased resistance, repetitions or duration are needed to enhance muscle strength and endurance (Garber et al., 2011). Currently, there are resistance putties with recommendations based on handgrip strength; however, when the current study was initiated, no such information was available. Therefore, as resistance could not be controlled, the number of repetitions was increased after four and eight weeks. This resulted in a programme that was too time-consuming, according to the participants (up to one hour per session). Participants thought that 10–20 repetitions would be feasible for their lifestyle. General exercise to improve endurance and strength has been shown to be safe and to have some beneficial effects on quality of life, muscle function, and physical and aerobic capacity in patients with PM and DM (Alemo Munters et al., 2013; Alexanderson and Lundberg, 2012; Alexanderson et al., 2000). The hand exercise programme used in the current study was well tolerated and did not lead to increased disease activity. However, it resulted in few individual improvements in hand function and almost none in activity limitation. This could have been because of the limited sample size or insufficient resistance of the putty. Future hand intervention studies would benefit from a larger sample size, a repeated-measure design and subgroup analysis, to evaluate the impact of gender, home- or hospitalbased exercise, and hand dominance and determine which patients would benefit from hand exercises. In conclusion, an occupational therapist-led hand exercise programme seems feasible to perform for patients with established PM or DM. Participants considered the programme to be too time-consuming, and hand function and activity performance improved in only a few of them, indicating a potential need to increase resistance in the exercise programme. 170

Acknowledgements We express our warm thanks to Anna Johansson, Christina Ottosson, Karina Gheorghe, Lara Dani, Louise Ekholm, Maryam Dastmalchi, Per-Johan Jakobsson and Susanna Farkas for their invaluable help in collecting data or administer the study. This study was supported by grants from Karolinska University Hospital, Karolinska Institutet (National Health Care Sciences Postgraduate School), the Swedish Research Council, the Swedish Rheumatism Association, King Gustaf V 80 Year Foundation, funds at the Karolinska Institutet and through the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet.

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