Speech therapy changes blood circulation and oxygenation in the brain and muscle

Introduction

Anthroposophic speech therapy (ATS) affects heart rate variability [1]. The aim of this pilot study was to investigate whether ATS also affects important physiological parameters, i.e. hemodynamics and tissue oxygenation in the brain and skeletal muscle of the leg measured by near infrared spectrophotometry (NIRS).

Material and methods

Seven subjects (professional speech therapists, 3 male, 4 female, age range 29–49 years) were measured during ATS. The measurement included 10min pre-baseline before reciting, 10min reciting a hexameter followed by 10min post-baseline. An ISS OxiplexTS NIRS instrument non-invasively measured oxy-, deoxy- and total hemoglobin (O₂Hb, HHb, tHb) and tissue oxygen saturation (S_tO₂). The last 5min of pre-baseline were compared with hexameter recitation and post-baseline by a paired t-test (* indicates p<0.05 and **p<0.01).

Results

In the leg, the tHb and HHb concentration decreased by (mean±SEM) 1.23±0.49μM* and 0.76±0.25μM*, respectively, during the first 5min of hexameter recitation and tHb increased by 0.75±0.29μM* during the last 5min of post-baseline. All other parameters did not change significantly.

In the brain during the first 5min of hexameter reciting, tHb, O₂Hb and S_tO₂ decreased by 1.01±0.36μM*, 1.16±0.32μM* and 1.22±0.30%**, respectively, and continued decreasing during the second 5min of recitation (tHb: 1.29±0.49μM*; O₂Hb: 1.75±0.54μM*; S_tO₂: 2.29±0.67%*). HHb did not change significantly during recitation. These findings can be interpreted as a decrease in cerebral blood flow.

During the post-baseline in the brain tHb returned and was not significantly different from pre-baseline. However, O₂Hb and S_tO₂ remained reduced during post-baseline for the first 5min by 1.55±0.48μM* and 2.83±0.53%** and second 5min by 1.19±0.44μM* and 2.77±0.55%**, while HHb increased by 0.94±0.08μM** during the first 5min and 1.08±0.15μM** during the second 5min of post-baseline. These findings can be interpreted as an increase in cerebral blood flow to baseline levels, while oxygen consumption in the brain increases, which corresponds to activation.

Conclusion

The results show that ATS leads to a decrease in cerebral blood flow during recitation and to brain activation thereafter.

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