Structural muscular adaptations in upper limb after stroke: a systematic review

Abstract

This review demonstrated little evidence with poor to fair quality on the structural muscle adaptations in the poststroke subjects, showing muscle atrophy, a higher stiffness, and amount of fibrous and fat tissue without alterations in lean tissue of distal muscles of the paretic UL compared to the nonparetic limb. However, the nonparetic side also presented alterations, which makes it an inappropriate comparison. Thus, well-designed studies addressing this issue are required.

Validity and reliability of myotonometry for assessing muscle viscoelastic properties in patients with stroke: a systematic review and meta-analysis

“…Although scores from different devices are correlated, particularly during active muscle contraction, this was only studied in young healthy males 53 . Second, spasticity-related muscle adaptations, both in the upper 54 and lower extremities 55 , may differ during different post stroke stages, although there is no clear evidence on this issue. In our review, only one research group investigated acute stroke patients 37,38 and a single study included subacute stroke participants 39 , which made it difficult and no relevant to perform a subgroup analysis.…”

Characterization of the Structural and Mechanical Changes of the Biceps Brachii and Gastrocnemius Muscles in the Subacute and Chronic Stage after Stroke

“…Current literature has characterized the muscle adaptations after stroke with SEMG [ 14 ], mechanomyography [ 24 ], and ultrasonography [ 6 , 8 ]. Myotonometry uses superficial mechanical deformation and represents a convenient approach that is considerably less costly than elastography [ 25 ] and has good psychometric properties [ 11 ].…”

“…These differences can be explained by the structural and functional adaptations that occur after stroke, such as variations in the number and length of sarcomeres in the skeletal muscles [ 29 ]. Additionally, reduced muscle thickness [ 6 ], together with increased tendon compliance and muscle pennation angle [ 30 ], leads to muscle atrophy, which is usually observed following prolonged disuse. In fact, disuse is considered the main factor involved in most of these muscular changes [ 6 ].…”

“…Structural changes in muscle and tendon appear as a result of PSS, leading to impaired motor control, disuse [ 3 ], worse recovery, and disability [ 4 ]. However, recent systematic reviews suggest that there is little, and conflicting, evidence about the specific structural and mechanical adaptations that occur in the upper and lower limb muscles after stroke [ 5 , 6 ]. Understanding this could help to guide clinical decisions aimed at targeting focal spasticity of specific muscles and locations within the muscles (i.e., botulin toxin) [ 7 ] or at restoring muscle function during physical rehabilitation [ 8 ].…”

Measuring Mechanical Properties of Spastic Muscles After Stroke. Does Muscle Position During Assessment Really Matter?

“…The general trend was toward higher tone and stiffness at the tendon, as already observed for the biceps brachii in people with Parkinson disease 43 and for the gastrocnemius in patients with spinal cord injury 44,45 and in healthy volunteers, 46,47 with conflicting evidence for the lower limb. 48 Structural adaptations associated with PSS, for example, lower MB tension with respect to the tendon 49 and lack of muscle strain during stretch 50 and with limb disuse after stroke 51 can help to support these results. Additionally, soft tissue mechanical properties may behave differently, depending on joint position during assessment, 47,52 which highlights again the importance of measuring different spots within the muscle to characterize PSS.…”