Research in Developmental Disabilities 34 (2013) 4343–4354
Contents lists available at ScienceDirect
Research in Developmental Disabilities
The effects of an exercise training program on hand and wrist strength, and function, and activities of daily living, in adults with severe Cerebral Palsy Yeshayahu Hutzler a,b,*, Beatriz Lamela Rodrı´guez c,d, Nuria Mendoza Laiz d,e, Isabel Dı´ez d, Sharon Barak f a
Zinman College of Physical Education and Sport Science, Israel Israel Sport Center for the Disabled, Israel Rey Carlos University of Madrid, Spain d CRE IMSerso, Ministry of Health, Social Affairs and Equality, Spain e University of Toledo, Spain f The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Israel b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 May 2013 Received in revised form 5 September 2013 Accepted 9 September 2013 Available online 18 October 2013
The purpose of the current study was to establish measurement reliability in adults with Cerebral Palsy (CP), and to examine the feasibility and outcomes of an upper extremity strength training program (three times per week for 90 min each time). A control group design mixed with a prospective time series design for the intervention group was completed, including a pre-test, a post-test after a 12-week intervention period, and a follow-up in the intervention group after an additional 10-week period. Seventeen adults with CP with severe motor impairment took part in the study (10 in the intervention and seven in the control group). The test battery was comprised of wrist and hand dynamometry; dominant hand upper-extremity function measures (Jebsen Hand Function Test = JHFT, Minnesota Manual Dexterity Test = MMDT, and the Nine Hole Peg Test = NHPT); and activity of daily living with the Barthel Index. The results indicated that in both the control and the intervention groups, the strength tests exhibited good-to-excellent reliability during pre-test and post-test. The group comparison revealed that while in the pre-test no between-group differences existed, in the post-test the strength training group demonstrated significantly higher values in five out of eight strength measures, as well as in the MMDT. Discontinuing the program for eight weeks reversed the effects almost to baseline. In conclusion, the outcomes demonstrated the reliability of the assessments utilized in this study, as well as the feasibility of the strength training program, in adults with severe motor impairment due to CP. ß 2013 Elsevier Ltd. All rights reserved.
Keywords: Assessment Fitness Physical activity Upper extremity Rehabilitation
1. Introduction Cerebral Palsy (CP) describes a group of permanent disorders of the development of movement and posture causing activity limitations, which are attributed to non-progressive disturbances that occur in the brain development of the fetus or
* Corresponding author at: Zinman College of Physical Education and Sport Sciences, Wingate Institute, 42902 Netanya, Israel. Tel.: +972 36484946; fax: +972 37511649. E-mail address: [email protected] (Y. Hutzler). 0891-4222/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2013.09.015
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infant. The motor impairment of CP is often accompanied by epilepsy; sensory abnormalities; and cognitive, perceptual, communication, and behavior disorders (see Krugger, 2006; Odding, Roebroeck, & Stam, 2006; Rosenbaum, Paneth, Leviton, Goldstein, & Bax, 2007). In an epidemiological survey of CP across Europe, an occurrence of 2.12–2.45 per 1000 live births was reported (Surveillance of Cerebral Palsy in Europe, 2002). The frequency of CP increases to 40–100 per 1000 preterm births (Odding et al., 2006). Every year there are approximately 10,000 newborns diagnosed with CP in the European Union (Surveillance of Cerebral Palsy in Europe, 2002). The prevalence of CP has not decreased, and some authors argue that in the past forty years it has even increased (Odding et al., 2006). It is estimated that 65–90% of children with CP survive to adulthood (Zaffuto-Sforza, 2005). The mean lifetime cost of treatment and lost income for a person with CP has been estimated in the United States as US$ 921,000 (CDC, 2004). The limitation of activity in CP typically leads to muscle weakness and atrophy (Bottos, Feliciangeli, & Sciuto, 2004), which increases in adulthood (Allen, Dodd, Taylor, McBurney, & Larkin, 2004). Most adults with CP, regardless of the degree of disability, have common limitations in performing activities of daily living (ADL; see Verschuren et al., 2011). The degree of functional performance in CP is typically classified across five categories by means of the Gross Motor Function Classification System (GMFCS; see Bax et al., 2005; Palisano, Rosenbaum, Bartlett, & Livingston, 2007), based on independence in locomotion and ranging from walks without limitations (Level I), through walks with limitations (Level II), walks using a handheld mobility device (Level III), self-mobility with limitations – may use powered mobility (Level IV), up to transported in a manual wheelchair (Level V). In a systematic review that extracted and summarized 10 clinical trials using strength training as their major intervention (Dodd, Taylor, & Damiano, 2002), it was reported that the majority exhibited a significant impact on strength with effect sizes ranging between 0.5 and 5.0. However, non-significant poor effects were seen in motor function, mostly walking. In a more recent systematic review performed with randomized clinical trials only (Scianni, Butler, Ada, & Teixeira-Salmela, 2009), the beneficial effect on strength was seen to diminish. However, most of this research has focused on children and adolescents with fair to moderate levels of functional limitation (i.e., GMFCS levels I–III; see Verschuren, Ketelaar, Takken, Helders, & Gorter, 2008). Moreover, there is very little evidence regarding the outcomes of strength training in adults with CP, particularly in those with severe functional limitations (GMFCS levels IV and V). Experts in rehabilitation and health promotion of persons with CP have addressed the significant role of being physically active and of physical training in functional ability and quality of life. For example Thorpe (2009) acknowledged that as more and more persons with CP lead meaningful lives into advanced age, it is imperative that the scientific community provide definitive information to help guide decisions related to the type and extent of fitness-related activities that might benefit these individuals. In addition, Zaffuto-Sforza (2005) reported that although there is an increasing awareness of the rights of people with disabilities, there is more work to be done particularly as relates to the cost and availability of adaptive equipment and exercise. Nevertheless, very few reports regarding the physical activity and functional ability of adults with CP have been published. In a study of 51 adults with CP, Gaskin and Morris (2008) reported very low physical activity participation rates, and a medium correlation between physical activity and functional ability (r = .45). In a more recent study (Maltais, Dumas, Boucher, & Richards, 2010), it was found that in individuals who were able to walk, inactivity was associated with an increase in the severity of additional health problems or complications. However, in non-walkers inactivity was most clearly associated with perceived range-of-motion limitations. In an intervention study of Andersson, Grooten, Hellsten, Kaping, and Mattsson (2003), ten adults with spastic diplegia who participated in strength training twice a week over 10 weeks, were compared to seven individuals with a similar disability who did not participate in training and served as controls. The authors reported significant improvements in the experimental groups in most outcome measures: (a) isometric strength of the hip extensors (p < .01) and hip abductors (p < .01), (b) isokinetic concentric work at 308 of the knee extensors (p < .05), (c) Gross Motor Function Measure (GMFM) dimensions D and E (p < .005), (d) walking velocity (p < .005), and (e) timed Up and Go (p < .01), while no change in these measures was observed in the controls. In addition, the authors noted that no adverse spasticity effects were encountered in the participants. Very limited information has been reported so far about the impact of a training program on the strength and motor function of the hand and wrist in rehabilitation clients with CP, all of them children or youth. O’Connell and Barnhart (1995) studied the effect of an eight-week upper body concentric resistance training program on wheelchair propulsion in three children with CP and three with Spina Bifida, aged 4–16 years. These authors reported significant increases in strength (sixrepetition maximal load in upper extremity muscle groups that are relevant for wheelchair propulsion) as well as distance covered in 12 min, suggesting that a specific muscle strengthening program could assist in wheelchair propulsion. A recent study performed on nine children with CP with a mean age of 9.1 years (SD = 1.8 years) reported improvement in the velocity of a reaching task at a comfortable speed as a result of a 10-week three times per week home based strength training program (Kim et al., 2012). Furthermore, the same reaching task as well as hand function in the Jebsen Taylor Hand Function Test (JHFT) improved significantly as a result of a Comprehensive Hand Repetitive Intensive Strength Training (CHRIST) program lasting 10 weeks, with three sessions of 60 min per week, in 10 children with CP with a mean age of 8.6 years (SD = 1.9 years; Lee et al., 2013). This program included body weight supported treadmill training for the upper limbs (body in quadruped position). So far no strength training outcomes on wrist and hand function have been reported in adults with CP. Therefore, the aim of the current study was to establish measurement efficacy in adults with CP who are unable to walk, and to examine the feasibility and efficacy of a strength training program designed to improve their strength and upper-extremity functionality.
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The specific research questions were: (a) Are the strength measurement devices reliable?; (b) Is a specifically designed strength training program in a group setting effective in increasing strength and function of the hand and wrist musculature, and in performance in daily life activities, of adults with CP?; (c) Will the effects of the strength training program, if achieved, be maintained after the program is discontinued?; and (d) What is the relationship between the strength and motor function variables? 2. Method A control group design mixed with a prospective time series design for the experimental group was completed, including a pre-test, a post-test after a 12-week intervention period, and a follow-up in the experimental group after an additional 10week period. 2.1. Participants Participants were rehabilitation clients in a Spanish state referral center for persons with severe disability, who were institutionalized for periods of 12–18 months with the aim of improving their functional level. A prospective cohort group design (Euser, Zoccali, Jager, & Dekker, 2009) was performed. One group participated in a strength training program offered to the residents, and the other did not participate. The total sample consisted of 17 adults with CP. In the strength training program (intervention group) 10 participants (six males and four females) with a mean age of 46.80 11.35 years took part. Their functional classification varied across GMFCS levels II (n = 2), III (n = 5) and IV (n = 3). The control group was comprised of seven participants (four males and three females) with a mean age of 39.85 14.43 years and GMFCS levels III (n = 3) and IV (n = 4). All participants were Caucasian. All participants underwent an individualized rehabilitation program, which included two physical therapy sessions (30 min each session) per week, in which stretching and tone management techniques were utilized to inhibit spasticity of the upper and lower extremities. In addition, two occupational therapy sessions were completed weekly (one hour each session) in which manipulative dexterity, as well as task-oriented reach, grip, and handling of different objects were performed. Inclusion criteria for the strength intervention and the comparison groups were: (a) scores of less than 45 out of 100 points in the Barthel Index (BI); (b) CP with involvement of all four limbs to a moderate extent; (c) functional ambulation in a wheelchair; and (d) a degree of muscle tone and range of motion that allows the performance of manual movements with objects such as weights and bands. Hand-dominance was determined by the hand used for all activities of daily living and for managing the joystick for electric-chair driving. Four participants had left-hand dominance and six participants had righthand dominance in the intervention group, while in the control group three were left-handed and four right-handed. The difference across groups was non significant (x2 = 1.92; p > .05) 2.2. Instruments 2.2.1. Severity of gross motor function The GMFCS (Palisano et al., 1997) was used to establish the participant’s severity of gross motor function. The GMFCS has been widely employed internationally to group individuals with CP into one of five levels, based on functional mobility or activity limitation (Holsbeeke, Ketelaar, Schoemaker, & Gorter, 2009). Level I represents the highest level of gross motor function, whereas level V represents the lowest level. Within the CP population, the GMFCS has good reliability and validity (Palisano et al., 1997). 2.2.2. Strength tests Participants were tested on eight strength tests: pinch key strength, three-jaw chuck pinch (tripod strength), tip-to-tip strength (fingertips strength), and five dynamometry power grasps. The first three tests were conducted with the Pinchmeter-P100 (NexGen Ergonomics Inc. Quebec, Canada). This device enables pinch strength to be accurately quantified in 0.1 increments (kg or lbs) from 0 to 22 kg or 0 to 50 lbs. The latter five power grasps were conducted with the Grip Dynamometer G100 (NexGen Ergonomics Inc., Quebec, Canada). This device can accurately measure five positions of grip strength (the grip positions differ in terms of the distance of the handle from the guide) in 0.1 increments (kgs or lbs), from 0 to 90 kg or 0 to 200 lbs. All sensors were connected to the Biometrics E-Link Ltd. (Newport, UK) computerized evaluation system, which was found to be valid and reliable for measuring grip and hand strength (e.g., Allen & Barnett, 2011; Goodson, McGregor, Douglas, & Taylor, 2007). In all the aforementioned hand strength tests, the measurements were repeated three times with the dominant hand and the mean of the three tests was registered (American Society of Hand Therapists, 1992). Following is a detailed description of the various hand strength tests. 2.2.2.1. Pinch key strength. According to the protocol of the American Society of Hand Therapists, the participants sat with their shoulder adducted and neutrally rotated, elbow flexed at 908 and the forearm and wrist in neutral position (Fess & Moran, 1981). In addition, the participants were asked to make a fist and to put the pinch gauge between the flexed proximal interphalangeal joint of the index finger and thumb (Mathiowetz et al., 1985).
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2.2.2.2. Three-jaw chuck pinch (tripod strength). The participants were asked to have their palm facing down and to place their index and middle fingers in the posterior component of the measurement device and their thumb on the pinch gauge. The pinky and ring fingers were in a flexed position. Following assumption of the appropriate position, the participants were asked to exert force between the pads of the index and middle fingers and the pad of the thumb, through the centers of the opposing pads (Imrhan & Rahman, 1995). 2.2.2.3. Tip-to-tip strength (fingertip strength). In this test, the participants were instructed to pinch the gauge between the thumb (in the anterior compartment of the device) and index finger (in the posterior compartment of the device), while the middle, ring and pinky fingers were in a flexed position. The forearm was in a pronation, supination or neutral position, while the wrist was in a neutral position. 2.2.2.4. Dynamometer test. Dynamometry positions (power grasps) 1 through 5 corresponded to a 3, 4, 6, 7, and 8 cm distance between the thumb and the opposing four fingers, respectively. In all five power grasps, the palm faced inward, toward the body. The total palmar hand surface grasped the dynamometer’s handle that ran parallel to the knuckles. The dynamometer faced away from the participant, such that the participant could not see or read the gauge (Mathiowetz et al., 1985). Strength was measured in each of the five different spans of the dynamometer. 2.2.3. Hand function tests The participants’ dominant hand functional level was assessed via the JHFT, the Minnesota Manual Dexterity Test (MMDT) and the Nine Hole Peg Test (NHPT). 2.2.3.1. JHFT. The JHFT (Jebsen, Taylor, Trieschmann, Trotter, & Howard, 1969) was developed to provide a standardized and objective evaluation of a broad range of uni-manual hand functions required for activities of daily living (ADL). The test consists of seven subtests, namely: writing a short sentence (24 letters, 3rd grade reading difficulty), turning over 7.6 by 12.7 cm cards, picking up small common objects (e.g., paper clips, pennies, bottle caps) and placing them in a container, simulated feeding, stacking checkers, picking up large light objects (empty cans), and picking up large heavy objects (weighted cans of 0.454 kg). The scoring method is the time (rounded to the nearest second) necessary to complete each subtest. The scores for all seven items can be summed for a total score. For the purpose of this study we analyzed each item separately. According to Jebsen et al., in a sample of 300 healthy individuals of different age groups (20–29 years, 30–39 years, 40–49 years, 50–59 years, and 60–94 years), each item took under 10 s to perform, with the exception of writing. Although the JHFT was not developed for participants with CP, it was indicated for those with neurological or musculoskeletal conditions (Cook, McCluskey, & Bowman, 2006), and has been used in practice for those with CP (e.g., Kinnucan, Ven Heest, & Tomhave, 2010; Van Heest, James, & Gerwin Carlson, 2012; Vaz, Cotta Mancini, Fonesca, Vieira, & de Melo Pertence, 2006) 2.2.3.2. MMDT. The MMDT is a test of manual dexterity (Trombly & Radomski, 2007). The testing kit consists of a plastic collapsible board with 60 holes (3.9 cm in diameter and 0.5 cm deep) and 60 cylindrical blocks (3.7 cm in diameter and 1.9 cm high). The complete MMDT Manual (Model 32023) incorporates five subtests: the Turning Test, the Placing Test, the Displacing Test, the One-hand Turning and Placing Test, and the Two-hand Turning and Placing Test (Surrey et al., 2003). In this study we used the abridged version (Model 32023), which includes the Turning and Placing tests only. Since the participants were unable to stand as requested in the manual, the tests were performed while sitting upright in the individual’s wheelchair. Each test was started with a 15-second practice trial for each subtest, and then repeated three times. The time of each test was recorded (rounded to the nearest second) and the average score of the three trials for each subtest was compiled (Lafayette Instrument Company, 1991). 2.2.3.3. NHPT. The NHPT is a quick test of finger dexterity (Mathiowetz et al., 1985). The test is composed of nine wooden pegs and a square board with nine holes, spaced 3.2 cm apart. The pegboard is centered in front of the subject and the participant is asked to take the pegs from a container, one by one, and place them into the holes on the board, as quickly as possible. Following this, the participants were asked to remove the pegs from the holes, one by one, and put them back into the container. The participant is entitled to hold the edge of the board with the hand not being evaluated in order to provide stability (Mathiowetz et al., 1985; Sommerfeld, Eek, Svensson, Holmqvist, & von Arbin, 2004). The scoring method is based on the time it takes to complete the test, recorded in seconds (Mathiowetz et al., 1985). 2.2.4. Activities of daily living The BI was used to establish the participant’s ability to independently ambulate and conduct ADL. More specifically, the BI assesses the following activities (items): feeding, bathing, grooming, dressing, bowel control, bladder control, toileting, chair transfer, ambulation and stair climbing. Each of the aforementioned items is rated based on the amount of assistance required to complete it (i.e., the individual can perform activities independently, with some assistance, or is dependent) (Mahoney & Barthel, 1965). The BI yields a total score out of 100. Higher scores denote a greater degree of functional independence (McDowell & Newell, 1996).
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All measurements were conducted three times: at baseline (pretest), immediately post intervention (post-test) and during follow-up (10 weeks after post-test). The observations and the administration of the tests were performed by two blinded evaluators. All the test trials were individually performed at the same time of the day in a controlled laboratory environment. 2.3. Intervention The intervention period lasted three months. The first four weeks focused on familiarizing the participants with the equipment, methods and exercises, since the majority of the participants were not experienced in fitness training. The subsequent eight weeks comprised the main training period, where three training sessions each (totaling 24 sessions) lasted a net time of 90 min within a two and a-half hour total time. Each session included four parts: (a) 10 min of warm-up and flexibility training of the upper extremity and trunk joints; (b) main specific training of the major muscle groups (i.e., biceps brachii, triceps brachii, pectoralis major and deltoid) during a 40–50 min duration; (c) a stretching period of the major muscle groups for 10 min; and (d) after about an hour’s rest, a second training period of the major muscle groups was performed lasting 30 min. The specific training was performed by experienced adapted physical activity coaches according to the recommendations of Rimmer (2012), posted on the National Center of Physical Activity and Disability (NCPAD) website. The training comprised of three sets of 8–10 repetitions, each with graded resistance. The resistance was accomplished using a variety of exercise equipment, including dumbbells, ‘‘digiflex’’ hand exercisers, elastic ‘‘thera’’ bands, springs, weighted bars, balls of different sizes, weights and contours, and sticky paste. Each type of equipment had varied resistance levels, which were clearly identified by different colors. The exercises were not time-based, and were adapted to the needs and capacity of each individual, based on his or her disability degree and trainability. The comparison group continued its regular rehabilitation activity. 2.4. Statistical analysis 2.4.1. Test–retest reliability of strength tests Participants were tested on eight strength tests (pinch key test, three point’s pressure test, fingertip-strength, and five dynamometry testing positions). Each test was repeated three times. Strength assessments’ test–retest reliability was determined by using the intraclass correlation coefficient (ICC). With trial and rater as random factors in the repeatedmeasures analysis of variance (ANOVA), ICC2,3 were calculated for test–retest reliability by using the mean of three measures (Shrout & Fleiss, 1979). The value of the ICC was interpreted as follows: poor (0.9) (Swets, 1988). In addition, between-trial differences were determined via repeated-measures one-way ANOVA and protected dependent t-tests with a significance level of 0.017 (0.05/3 = 0.017). Prior to the repeated measures ANOVA test, data which did not correspond with the homogeneity of variance assumption were transformed. The results indicated that in both the control and the intervention groups, the eight strength tests had good-to-excellent reliability during pre-test and post-test (an additional description of the test–retest reliability results appears in the Results section). Therefore, additional analyses were conducted with the mean of each of the eight strength tests. 2.4.2. Strength training effect Assessment of the effect of the strength training for individuals with CP was established via a two-step process. In the first step, pre-test and post-test mean differences between the control and intervention groups were compared using an independent samples t-test. Level of significance was set at 0.05 and adjusted to
Contents lists available at ScienceDirect
Research in Developmental Disabilities
The effects of an exercise training program on hand and wrist strength, and function, and activities of daily living, in adults with severe Cerebral Palsy Yeshayahu Hutzler a,b,*, Beatriz Lamela Rodrı´guez c,d, Nuria Mendoza Laiz d,e, Isabel Dı´ez d, Sharon Barak f a
Zinman College of Physical Education and Sport Science, Israel Israel Sport Center for the Disabled, Israel Rey Carlos University of Madrid, Spain d CRE IMSerso, Ministry of Health, Social Affairs and Equality, Spain e University of Toledo, Spain f The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Israel b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 May 2013 Received in revised form 5 September 2013 Accepted 9 September 2013 Available online 18 October 2013
The purpose of the current study was to establish measurement reliability in adults with Cerebral Palsy (CP), and to examine the feasibility and outcomes of an upper extremity strength training program (three times per week for 90 min each time). A control group design mixed with a prospective time series design for the intervention group was completed, including a pre-test, a post-test after a 12-week intervention period, and a follow-up in the intervention group after an additional 10-week period. Seventeen adults with CP with severe motor impairment took part in the study (10 in the intervention and seven in the control group). The test battery was comprised of wrist and hand dynamometry; dominant hand upper-extremity function measures (Jebsen Hand Function Test = JHFT, Minnesota Manual Dexterity Test = MMDT, and the Nine Hole Peg Test = NHPT); and activity of daily living with the Barthel Index. The results indicated that in both the control and the intervention groups, the strength tests exhibited good-to-excellent reliability during pre-test and post-test. The group comparison revealed that while in the pre-test no between-group differences existed, in the post-test the strength training group demonstrated significantly higher values in five out of eight strength measures, as well as in the MMDT. Discontinuing the program for eight weeks reversed the effects almost to baseline. In conclusion, the outcomes demonstrated the reliability of the assessments utilized in this study, as well as the feasibility of the strength training program, in adults with severe motor impairment due to CP. ß 2013 Elsevier Ltd. All rights reserved.
Keywords: Assessment Fitness Physical activity Upper extremity Rehabilitation
1. Introduction Cerebral Palsy (CP) describes a group of permanent disorders of the development of movement and posture causing activity limitations, which are attributed to non-progressive disturbances that occur in the brain development of the fetus or
* Corresponding author at: Zinman College of Physical Education and Sport Sciences, Wingate Institute, 42902 Netanya, Israel. Tel.: +972 36484946; fax: +972 37511649. E-mail address: [email protected] (Y. Hutzler). 0891-4222/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2013.09.015
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infant. The motor impairment of CP is often accompanied by epilepsy; sensory abnormalities; and cognitive, perceptual, communication, and behavior disorders (see Krugger, 2006; Odding, Roebroeck, & Stam, 2006; Rosenbaum, Paneth, Leviton, Goldstein, & Bax, 2007). In an epidemiological survey of CP across Europe, an occurrence of 2.12–2.45 per 1000 live births was reported (Surveillance of Cerebral Palsy in Europe, 2002). The frequency of CP increases to 40–100 per 1000 preterm births (Odding et al., 2006). Every year there are approximately 10,000 newborns diagnosed with CP in the European Union (Surveillance of Cerebral Palsy in Europe, 2002). The prevalence of CP has not decreased, and some authors argue that in the past forty years it has even increased (Odding et al., 2006). It is estimated that 65–90% of children with CP survive to adulthood (Zaffuto-Sforza, 2005). The mean lifetime cost of treatment and lost income for a person with CP has been estimated in the United States as US$ 921,000 (CDC, 2004). The limitation of activity in CP typically leads to muscle weakness and atrophy (Bottos, Feliciangeli, & Sciuto, 2004), which increases in adulthood (Allen, Dodd, Taylor, McBurney, & Larkin, 2004). Most adults with CP, regardless of the degree of disability, have common limitations in performing activities of daily living (ADL; see Verschuren et al., 2011). The degree of functional performance in CP is typically classified across five categories by means of the Gross Motor Function Classification System (GMFCS; see Bax et al., 2005; Palisano, Rosenbaum, Bartlett, & Livingston, 2007), based on independence in locomotion and ranging from walks without limitations (Level I), through walks with limitations (Level II), walks using a handheld mobility device (Level III), self-mobility with limitations – may use powered mobility (Level IV), up to transported in a manual wheelchair (Level V). In a systematic review that extracted and summarized 10 clinical trials using strength training as their major intervention (Dodd, Taylor, & Damiano, 2002), it was reported that the majority exhibited a significant impact on strength with effect sizes ranging between 0.5 and 5.0. However, non-significant poor effects were seen in motor function, mostly walking. In a more recent systematic review performed with randomized clinical trials only (Scianni, Butler, Ada, & Teixeira-Salmela, 2009), the beneficial effect on strength was seen to diminish. However, most of this research has focused on children and adolescents with fair to moderate levels of functional limitation (i.e., GMFCS levels I–III; see Verschuren, Ketelaar, Takken, Helders, & Gorter, 2008). Moreover, there is very little evidence regarding the outcomes of strength training in adults with CP, particularly in those with severe functional limitations (GMFCS levels IV and V). Experts in rehabilitation and health promotion of persons with CP have addressed the significant role of being physically active and of physical training in functional ability and quality of life. For example Thorpe (2009) acknowledged that as more and more persons with CP lead meaningful lives into advanced age, it is imperative that the scientific community provide definitive information to help guide decisions related to the type and extent of fitness-related activities that might benefit these individuals. In addition, Zaffuto-Sforza (2005) reported that although there is an increasing awareness of the rights of people with disabilities, there is more work to be done particularly as relates to the cost and availability of adaptive equipment and exercise. Nevertheless, very few reports regarding the physical activity and functional ability of adults with CP have been published. In a study of 51 adults with CP, Gaskin and Morris (2008) reported very low physical activity participation rates, and a medium correlation between physical activity and functional ability (r = .45). In a more recent study (Maltais, Dumas, Boucher, & Richards, 2010), it was found that in individuals who were able to walk, inactivity was associated with an increase in the severity of additional health problems or complications. However, in non-walkers inactivity was most clearly associated with perceived range-of-motion limitations. In an intervention study of Andersson, Grooten, Hellsten, Kaping, and Mattsson (2003), ten adults with spastic diplegia who participated in strength training twice a week over 10 weeks, were compared to seven individuals with a similar disability who did not participate in training and served as controls. The authors reported significant improvements in the experimental groups in most outcome measures: (a) isometric strength of the hip extensors (p < .01) and hip abductors (p < .01), (b) isokinetic concentric work at 308 of the knee extensors (p < .05), (c) Gross Motor Function Measure (GMFM) dimensions D and E (p < .005), (d) walking velocity (p < .005), and (e) timed Up and Go (p < .01), while no change in these measures was observed in the controls. In addition, the authors noted that no adverse spasticity effects were encountered in the participants. Very limited information has been reported so far about the impact of a training program on the strength and motor function of the hand and wrist in rehabilitation clients with CP, all of them children or youth. O’Connell and Barnhart (1995) studied the effect of an eight-week upper body concentric resistance training program on wheelchair propulsion in three children with CP and three with Spina Bifida, aged 4–16 years. These authors reported significant increases in strength (sixrepetition maximal load in upper extremity muscle groups that are relevant for wheelchair propulsion) as well as distance covered in 12 min, suggesting that a specific muscle strengthening program could assist in wheelchair propulsion. A recent study performed on nine children with CP with a mean age of 9.1 years (SD = 1.8 years) reported improvement in the velocity of a reaching task at a comfortable speed as a result of a 10-week three times per week home based strength training program (Kim et al., 2012). Furthermore, the same reaching task as well as hand function in the Jebsen Taylor Hand Function Test (JHFT) improved significantly as a result of a Comprehensive Hand Repetitive Intensive Strength Training (CHRIST) program lasting 10 weeks, with three sessions of 60 min per week, in 10 children with CP with a mean age of 8.6 years (SD = 1.9 years; Lee et al., 2013). This program included body weight supported treadmill training for the upper limbs (body in quadruped position). So far no strength training outcomes on wrist and hand function have been reported in adults with CP. Therefore, the aim of the current study was to establish measurement efficacy in adults with CP who are unable to walk, and to examine the feasibility and efficacy of a strength training program designed to improve their strength and upper-extremity functionality.
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The specific research questions were: (a) Are the strength measurement devices reliable?; (b) Is a specifically designed strength training program in a group setting effective in increasing strength and function of the hand and wrist musculature, and in performance in daily life activities, of adults with CP?; (c) Will the effects of the strength training program, if achieved, be maintained after the program is discontinued?; and (d) What is the relationship between the strength and motor function variables? 2. Method A control group design mixed with a prospective time series design for the experimental group was completed, including a pre-test, a post-test after a 12-week intervention period, and a follow-up in the experimental group after an additional 10week period. 2.1. Participants Participants were rehabilitation clients in a Spanish state referral center for persons with severe disability, who were institutionalized for periods of 12–18 months with the aim of improving their functional level. A prospective cohort group design (Euser, Zoccali, Jager, & Dekker, 2009) was performed. One group participated in a strength training program offered to the residents, and the other did not participate. The total sample consisted of 17 adults with CP. In the strength training program (intervention group) 10 participants (six males and four females) with a mean age of 46.80 11.35 years took part. Their functional classification varied across GMFCS levels II (n = 2), III (n = 5) and IV (n = 3). The control group was comprised of seven participants (four males and three females) with a mean age of 39.85 14.43 years and GMFCS levels III (n = 3) and IV (n = 4). All participants were Caucasian. All participants underwent an individualized rehabilitation program, which included two physical therapy sessions (30 min each session) per week, in which stretching and tone management techniques were utilized to inhibit spasticity of the upper and lower extremities. In addition, two occupational therapy sessions were completed weekly (one hour each session) in which manipulative dexterity, as well as task-oriented reach, grip, and handling of different objects were performed. Inclusion criteria for the strength intervention and the comparison groups were: (a) scores of less than 45 out of 100 points in the Barthel Index (BI); (b) CP with involvement of all four limbs to a moderate extent; (c) functional ambulation in a wheelchair; and (d) a degree of muscle tone and range of motion that allows the performance of manual movements with objects such as weights and bands. Hand-dominance was determined by the hand used for all activities of daily living and for managing the joystick for electric-chair driving. Four participants had left-hand dominance and six participants had righthand dominance in the intervention group, while in the control group three were left-handed and four right-handed. The difference across groups was non significant (x2 = 1.92; p > .05) 2.2. Instruments 2.2.1. Severity of gross motor function The GMFCS (Palisano et al., 1997) was used to establish the participant’s severity of gross motor function. The GMFCS has been widely employed internationally to group individuals with CP into one of five levels, based on functional mobility or activity limitation (Holsbeeke, Ketelaar, Schoemaker, & Gorter, 2009). Level I represents the highest level of gross motor function, whereas level V represents the lowest level. Within the CP population, the GMFCS has good reliability and validity (Palisano et al., 1997). 2.2.2. Strength tests Participants were tested on eight strength tests: pinch key strength, three-jaw chuck pinch (tripod strength), tip-to-tip strength (fingertips strength), and five dynamometry power grasps. The first three tests were conducted with the Pinchmeter-P100 (NexGen Ergonomics Inc. Quebec, Canada). This device enables pinch strength to be accurately quantified in 0.1 increments (kg or lbs) from 0 to 22 kg or 0 to 50 lbs. The latter five power grasps were conducted with the Grip Dynamometer G100 (NexGen Ergonomics Inc., Quebec, Canada). This device can accurately measure five positions of grip strength (the grip positions differ in terms of the distance of the handle from the guide) in 0.1 increments (kgs or lbs), from 0 to 90 kg or 0 to 200 lbs. All sensors were connected to the Biometrics E-Link Ltd. (Newport, UK) computerized evaluation system, which was found to be valid and reliable for measuring grip and hand strength (e.g., Allen & Barnett, 2011; Goodson, McGregor, Douglas, & Taylor, 2007). In all the aforementioned hand strength tests, the measurements were repeated three times with the dominant hand and the mean of the three tests was registered (American Society of Hand Therapists, 1992). Following is a detailed description of the various hand strength tests. 2.2.2.1. Pinch key strength. According to the protocol of the American Society of Hand Therapists, the participants sat with their shoulder adducted and neutrally rotated, elbow flexed at 908 and the forearm and wrist in neutral position (Fess & Moran, 1981). In addition, the participants were asked to make a fist and to put the pinch gauge between the flexed proximal interphalangeal joint of the index finger and thumb (Mathiowetz et al., 1985).
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2.2.2.2. Three-jaw chuck pinch (tripod strength). The participants were asked to have their palm facing down and to place their index and middle fingers in the posterior component of the measurement device and their thumb on the pinch gauge. The pinky and ring fingers were in a flexed position. Following assumption of the appropriate position, the participants were asked to exert force between the pads of the index and middle fingers and the pad of the thumb, through the centers of the opposing pads (Imrhan & Rahman, 1995). 2.2.2.3. Tip-to-tip strength (fingertip strength). In this test, the participants were instructed to pinch the gauge between the thumb (in the anterior compartment of the device) and index finger (in the posterior compartment of the device), while the middle, ring and pinky fingers were in a flexed position. The forearm was in a pronation, supination or neutral position, while the wrist was in a neutral position. 2.2.2.4. Dynamometer test. Dynamometry positions (power grasps) 1 through 5 corresponded to a 3, 4, 6, 7, and 8 cm distance between the thumb and the opposing four fingers, respectively. In all five power grasps, the palm faced inward, toward the body. The total palmar hand surface grasped the dynamometer’s handle that ran parallel to the knuckles. The dynamometer faced away from the participant, such that the participant could not see or read the gauge (Mathiowetz et al., 1985). Strength was measured in each of the five different spans of the dynamometer. 2.2.3. Hand function tests The participants’ dominant hand functional level was assessed via the JHFT, the Minnesota Manual Dexterity Test (MMDT) and the Nine Hole Peg Test (NHPT). 2.2.3.1. JHFT. The JHFT (Jebsen, Taylor, Trieschmann, Trotter, & Howard, 1969) was developed to provide a standardized and objective evaluation of a broad range of uni-manual hand functions required for activities of daily living (ADL). The test consists of seven subtests, namely: writing a short sentence (24 letters, 3rd grade reading difficulty), turning over 7.6 by 12.7 cm cards, picking up small common objects (e.g., paper clips, pennies, bottle caps) and placing them in a container, simulated feeding, stacking checkers, picking up large light objects (empty cans), and picking up large heavy objects (weighted cans of 0.454 kg). The scoring method is the time (rounded to the nearest second) necessary to complete each subtest. The scores for all seven items can be summed for a total score. For the purpose of this study we analyzed each item separately. According to Jebsen et al., in a sample of 300 healthy individuals of different age groups (20–29 years, 30–39 years, 40–49 years, 50–59 years, and 60–94 years), each item took under 10 s to perform, with the exception of writing. Although the JHFT was not developed for participants with CP, it was indicated for those with neurological or musculoskeletal conditions (Cook, McCluskey, & Bowman, 2006), and has been used in practice for those with CP (e.g., Kinnucan, Ven Heest, & Tomhave, 2010; Van Heest, James, & Gerwin Carlson, 2012; Vaz, Cotta Mancini, Fonesca, Vieira, & de Melo Pertence, 2006) 2.2.3.2. MMDT. The MMDT is a test of manual dexterity (Trombly & Radomski, 2007). The testing kit consists of a plastic collapsible board with 60 holes (3.9 cm in diameter and 0.5 cm deep) and 60 cylindrical blocks (3.7 cm in diameter and 1.9 cm high). The complete MMDT Manual (Model 32023) incorporates five subtests: the Turning Test, the Placing Test, the Displacing Test, the One-hand Turning and Placing Test, and the Two-hand Turning and Placing Test (Surrey et al., 2003). In this study we used the abridged version (Model 32023), which includes the Turning and Placing tests only. Since the participants were unable to stand as requested in the manual, the tests were performed while sitting upright in the individual’s wheelchair. Each test was started with a 15-second practice trial for each subtest, and then repeated three times. The time of each test was recorded (rounded to the nearest second) and the average score of the three trials for each subtest was compiled (Lafayette Instrument Company, 1991). 2.2.3.3. NHPT. The NHPT is a quick test of finger dexterity (Mathiowetz et al., 1985). The test is composed of nine wooden pegs and a square board with nine holes, spaced 3.2 cm apart. The pegboard is centered in front of the subject and the participant is asked to take the pegs from a container, one by one, and place them into the holes on the board, as quickly as possible. Following this, the participants were asked to remove the pegs from the holes, one by one, and put them back into the container. The participant is entitled to hold the edge of the board with the hand not being evaluated in order to provide stability (Mathiowetz et al., 1985; Sommerfeld, Eek, Svensson, Holmqvist, & von Arbin, 2004). The scoring method is based on the time it takes to complete the test, recorded in seconds (Mathiowetz et al., 1985). 2.2.4. Activities of daily living The BI was used to establish the participant’s ability to independently ambulate and conduct ADL. More specifically, the BI assesses the following activities (items): feeding, bathing, grooming, dressing, bowel control, bladder control, toileting, chair transfer, ambulation and stair climbing. Each of the aforementioned items is rated based on the amount of assistance required to complete it (i.e., the individual can perform activities independently, with some assistance, or is dependent) (Mahoney & Barthel, 1965). The BI yields a total score out of 100. Higher scores denote a greater degree of functional independence (McDowell & Newell, 1996).
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All measurements were conducted three times: at baseline (pretest), immediately post intervention (post-test) and during follow-up (10 weeks after post-test). The observations and the administration of the tests were performed by two blinded evaluators. All the test trials were individually performed at the same time of the day in a controlled laboratory environment. 2.3. Intervention The intervention period lasted three months. The first four weeks focused on familiarizing the participants with the equipment, methods and exercises, since the majority of the participants were not experienced in fitness training. The subsequent eight weeks comprised the main training period, where three training sessions each (totaling 24 sessions) lasted a net time of 90 min within a two and a-half hour total time. Each session included four parts: (a) 10 min of warm-up and flexibility training of the upper extremity and trunk joints; (b) main specific training of the major muscle groups (i.e., biceps brachii, triceps brachii, pectoralis major and deltoid) during a 40–50 min duration; (c) a stretching period of the major muscle groups for 10 min; and (d) after about an hour’s rest, a second training period of the major muscle groups was performed lasting 30 min. The specific training was performed by experienced adapted physical activity coaches according to the recommendations of Rimmer (2012), posted on the National Center of Physical Activity and Disability (NCPAD) website. The training comprised of three sets of 8–10 repetitions, each with graded resistance. The resistance was accomplished using a variety of exercise equipment, including dumbbells, ‘‘digiflex’’ hand exercisers, elastic ‘‘thera’’ bands, springs, weighted bars, balls of different sizes, weights and contours, and sticky paste. Each type of equipment had varied resistance levels, which were clearly identified by different colors. The exercises were not time-based, and were adapted to the needs and capacity of each individual, based on his or her disability degree and trainability. The comparison group continued its regular rehabilitation activity. 2.4. Statistical analysis 2.4.1. Test–retest reliability of strength tests Participants were tested on eight strength tests (pinch key test, three point’s pressure test, fingertip-strength, and five dynamometry testing positions). Each test was repeated three times. Strength assessments’ test–retest reliability was determined by using the intraclass correlation coefficient (ICC). With trial and rater as random factors in the repeatedmeasures analysis of variance (ANOVA), ICC2,3 were calculated for test–retest reliability by using the mean of three measures (Shrout & Fleiss, 1979). The value of the ICC was interpreted as follows: poor (0.9) (Swets, 1988). In addition, between-trial differences were determined via repeated-measures one-way ANOVA and protected dependent t-tests with a significance level of 0.017 (0.05/3 = 0.017). Prior to the repeated measures ANOVA test, data which did not correspond with the homogeneity of variance assumption were transformed. The results indicated that in both the control and the intervention groups, the eight strength tests had good-to-excellent reliability during pre-test and post-test (an additional description of the test–retest reliability results appears in the Results section). Therefore, additional analyses were conducted with the mean of each of the eight strength tests. 2.4.2. Strength training effect Assessment of the effect of the strength training for individuals with CP was established via a two-step process. In the first step, pre-test and post-test mean differences between the control and intervention groups were compared using an independent samples t-test. Level of significance was set at 0.05 and adjusted to
