Fig 5. Scatterplot of the differences between negative MD and PSD values with regard to the MDs of the enrolled patients.

The “broken stick” model is designated by the black line. The tipping point was −14.0 dB (95% confidence interval, −16.2 ~ −11.8 dB, P < 0.001); the slope below the tipping point was given by Y = −18.469 − 1.328X and the slope above the tipping point was given by Y = −0.445 − 0.043X (P < 0.0001).