Journal of Rehabilitation Medicine 51-4inkOmslag | Page 14

J Rehabil Med 2019; 51: 248–256 ORIGINAL REPORT DEVELOPMENT OF GRIP STRENGTH DURING THE FIRST YEAR AFTER STROKE Roland STOCK, MSc 1,2 , Gyrd THRANE, PhD 3 , Torunn ASKIM, PhD 2 , Audny ANKE, MD, PhD 4,5 and Paul Jarle MORK, PhD 6 From the 1 Department of Physical Medicine and Rehabilitation, Trondheim University Hospital, 2 Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Science, NTNU - Norwegian University of Science and Technology, 3 Department of Health and Care Sciences, UiT The Arctic University of Norway, 4 Department of Rehabilitation, University Hospital of North Norway, 5 Department of Clinical Medicine, UiT The Arctic University of Norway, and 6 Department of Public Health and Nursing, Faculty of Medicine and Health Science, NTNU - Norwegian University of Science and Technology, Trondheim, Norway Objective: To assess recovery of grip strength during the first year post-stroke. Design: Exploratory study on a subsample of pa- tients participating in the Norwegian Constraint-In- duced Movement Therapy trial. Subjects: Eleven patients (mean age 59.1 years; 3 women) with mild to moderate stroke were recrui- ted 7–29 days post-stroke. Methods: An electronic dynamometer (Biometrics Ltd, Gwent, UK, 2006) was used to assess maximum grip force in 5 hand positions, rate of force develop- ment and sustainability of grip force. Similar assess- ments were performed to assess pinch strength. The participants were assessed 5 times during a 1-year period. Results: Grip force in the affected hand increased in all handle positions during the 1-year follow-up, mostly during the first 6 months. At 2 and 4 weeks, rate of force development was less than half, and relative sustainability of grip force showed 20–30% greater deficit than for the non-affected hand. The affected hand approached the values of the non-af- fected hand after 6 months with little further pro- gress until 1-year follow-up. Conclusion: Grip strength in the affected hand impro- ved considerably in the first year post-stroke. Pat- terns of improvement were similar across tests, i.e. rapid during the first weeks, slower until 6 months, and minimal 6–12 months post-stroke. Key words: stroke; rehabilitation; hand strength; pinch strength; muscle fatigue. Accepted Jan 28, 2019; Epub ahead of print Mar 8, 2019 J Rehabil Med 2019; 51: 248–256 Correspondence address: Roland Stock, Department of Physical Medi- cine and Rehabilitation, Trondheim University Hospital, Vådanveien 39, NO-7024 Trondheim, Norway. E-mail: [email protected] S troke often leads to muscle weakness and less ef- fective and coordinated movements in the affected upper limb during activities of daily living (ADL) (1). Most improvements in overall motor function occur during the first year after the stroke, with less progress after 6 months and a fairly stable motor function from 12 months post-stroke (2). Grip strength of both the whole palm and the fingers are important for upper limb function (3) and several LAY ABSTRACT Grip strength is often reduced after a stroke. This affects the ability to maintain grip strength over time and to in- crease force rapidly. Consequently, this also reduces the ability to cope with everyday activities. This study found that these aspects of grip strength were considerably reduced in the affected hand during the first weeks after stroke in patients with mild to moderate stroke. How­ ever, the participants showed good progress during the first year after stroke. All aspects of grip strength impro- ved considerably, especially during the first 6 months. To optimize the improvement in hand function, stroke rehabilitation should have a specific focus on all aspects of grip strength. For instance, practicing the ability to maintain a powerful grip while carrying a shopping bag or increasing force rapidly while squeezing an object. studies have shown that grip strength is positively cor- related with motor function and ADL performance (4, 5). However, few studies have measured grip strength with follow-up beyond 3 months (6, 7) and a detailed description of the long-term recovery of hand muscle function is currently lacking. Furthermore, it has been shown that the elbow flexor and extensor muscles in the affected arm in persons with stroke are relatively weaker in their shortened range (8); however, it is unclear if such selective weakness also applies to hand muscles. In addition to a reduction in muscle strength, the for- ce-time characteristics (i.e. rate of force development and sustainability of grip force) are altered in persons with stroke. Canning et al. (9) found that persons with stroke have reduced rate of force development capacity in the elbow flexor and extensor muscles compared with healthy controls. Similar results have been found for ankle plantar flexor muscles (10). However, little is known about rate of force development in the hand muscles in persons with stroke and how rate of force development evolves during the first year post-stroke. Furthermore, some studies indicate reduced sustainabi- lity of grip force in persons with stroke. Kamimura & Ikuta (11) assessed the decline in maximum sustained grip force as the percentage of maximum voluntary contraction (MVC) force, and found that the affected hand reached values less than 80% faster than the non- affected hand. However, there is limited knowledge This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm doi: 10.2340/16501977-2530 Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977