Ischemic Conditioning Enhances Corticomotor Excitability, Strength, and Motor Control in the Short Term After Chronic...

This study aimed to evaluate the corticomotor mechanisms and short-term motor effects of ischemic conditioning (IC) applied to the paretic leg in individuals with chronic stroke. We hypothesized that IC would enhance ipsilesional corticomotor excitability (CME), strengthen ipsilesional-to-contralesional transcallosal inhibition (TCI), and improve knee and ankle strength and ankle motor control compared with sham, with effects persisting for ≥30 minutes.

Nineteen chronic stroke survivors (15 men; aged 60.9 ± 7.0 years; time since stroke 7.6 ± 4.8 years; and Fugl-Meyer Lower Extremity Assessment 22.3 ± 6.4) experienced one session of IC and sham-IC. Transcranial magnetic stimulation measured CME from the ipsilesional M1 to the paretic tibialis anterior (TA) and TCI from the ipsilesional to contralesional M1. Motor performance was evaluated using knee and ankle strength and paretic ankle reaction time. CME was the primary outcome; all other outcomes were considered exploratory. All outcomes were measured before, immediately post, and 30 minutes post each intervention. Data across timepoints and conditions were analyzed using two-way repeated-measures analyses of variance with significance levels set at p < 0.05.

IC increased CME of the paretic TA (0.02mV ± 0.19mV; p = 0.011) and ipsilesional-to-contralesional TCI (17.1 ± 44.9 milliseconds; p = < 0.001). Paretic ankle reaction time improved after IC (-0.08 ± 0.22 milliseconds; p = 0.007). Paretic knee extension (0.46 ± 1.8 lb.s; p = 0.04), dorsiflexion (0.28 ± 1.2 lb.s; p = 0.044), and plantarflexion (0.55 ± 1.4 lb.s; p = 0.01) strength, in addition to nonparetic plantarflexion strength (0.52 ± 0.8 lb.s; p = 0.018), also improved after IC. All paretic muscle changes were sustained at 30 minutes. No changes were observed during the sham condition.

This study provides preliminary evidence that one session of paretic leg IC enhances CME, interhemispheric inhibition, and motor performance in the short term in chronic stroke. These findings suggest that IC may serve as a feasible neuromodulatory adjunct to poststroke rehabilitation, although larger and multisession studies are needed to determine durability and clinical relevance.

The Clinicaltrials.gov registration number for the study is NCT05906602.