Muscle quality improvement in subacute post-stroke patients after rehabilitation: Usefulness of segmental phase angle from bioelectrical impedance analysis.

Background & Aims: During stroke rehabilitation, the whole-body Phase Angle (PhA) from Bioelectrical Impedance Analysis (BIA) is measured to assess whole-body muscle quality, which reflects cellular integrity and function. The segmental BIA is a valuable method for assessing the body composition of specific body segments, such as the arms, legs, and hemisoma. After a stroke insult, patients frequently experience hemiparesis, and segmental PhA from segmental BIA appears to be an appropriate parameter for examining the muscle quality of affected and unaffected limbs separately. This study aims to investigate whether segmental PhA is more informative than whole-body PhA in (a) assessing the deterioration of muscle quality in post-stroke patients and (b) monitoring its recovery following rehabilitative treatment.

Methods: This longitudinal study recruited subacute post-stroke patients who were admitted to our rehabilitation center. At admission, demographic, anamnestic, and clinical information, such as the presence of comorbidities, were recorded. BIA was used to evaluate the whole-body PhA and segmental PhA of the affected and unaffected hemisoma, arms, and legs at admission (T0) and after a six-week rehabilitation program (T1). The modified Barthel Index (mBI), Fugl-Meyer Assessment for the Upper Extremity (FMA-UE), and Motricity Index of the Upper (MI-UE) and Lower (MI-LE) Extremities were evaluated at T0 and T1 to determine the patient's Activity of Daily Living (ADL) performance, upper limb motor performance, and upper and lower limb muscle strength, respectively.

Results: We evaluated segmental and whole-body BIA in 70 subacute post-stroke patients (women n = 34, ischemic n = 56, mean age 70 ± 11) at T0 and T1. Whole-body PhA values of the patients were below the normal range. Considering segmental data, the affected hemisoma, arm, and leg had considerably lower PhA values as compared to the unaffected body segments. Furthermore, at T1, the PhA values of all affected body segments improved, while those of the unaffected ones and whole-body PhA did not. At both T0 and T1, the segmental PhA values of the affected body segments showed to be related with all clinical outcome measures, while whole-body PhA correlated only with mBI.

Conclusions: This study emphasizes the significance of measuring segmental PhA in hemiparetic subacute stroke patients undergoing rehabilitation treatment. Segmental PhA is a more accurate parameter to evaluate rehabilitation treatment in patients with hemiparesis because it can distinguish affected from unaffected body segments, hence facilitating accurate monitoring of muscle quality improvements resulting from a rehabilitation program.