Retinal microvascular and microcirculatory responses related to cognition improvement following yoga training in patients with Parkinson's disease.

PURPOSE

To determine the relationship of retinal microcirculatory responses to cognitive function following yoga training in patients with Parkinson's disease (PD).

METHODS

Twenty patients with diagnosed PD were recruited, and retinal imaging was successful on 17 patients (age 71.8 ± 7.2 years old, nine females). Retinal capillary perfusion density (CPD) was imaged using optical coherence tomography angiography (OCTA), and retinal blood flow (RBF) was imaged using a retinal function imager (RFI). All patients participated in three 1-hour YogaCue or Hatha yoga classes per week for 24 consecutive weeks. Pearson correlation analyses determined the relationship between the changes in retinal microcirculatory responses and cognitive function.

RESULTS

Increased RBF was significantly related to the changes of CPD in all retinal slabs, including superficial and deeper vascular plexuses and retinal vascular network (6 mm scan, r ranged 0.58-0.83, P < 0.05). The increased RBF and CPD of superficial vascular plexus (6 mm scan) were related to the improvements (i.e., shorter time) in trail-making A performance (r = -0.66, P < 0.01 and r = -0.58, P < 0.05, respectively). In addition, the change of CPD in the retinal vascular network was related to improvement in Hopkins verbal delayed recall (r = 0.50, P < 0.05).

CONCLUSION

This is the first study exploring the relationship between retinal microcirculatory responses to yoga exercise and cognitive function in PD patients. The synergistic effect of CPD and RBF may be developed into ocular indicators for monitoring the effect of cognitive improvement from yoga exercise in patients with PD.