Table 2.

Delta of log LF/HF between posttreatment recording periods T + 1 through T + 4 and period T − 1 (pretreatment) and its correlation with delta of levels of intensity of pain prior to pain treatment (PT0) and 30 minutes after initiation of pain treatment (PT30)

Period of log LF/HF recording and correlation coefficient		PT0 – PT30
Log LF/HF, T − 1 minus T + 1	r	0.653
	p	0.079
Log LF/HF, T − 1 minus T + 2	r	0.730*
	p	0.040
Log LF/HF, T − 1 minus T + 3	r	0.866*
	p	0.005
Log LF/HF, T − 1 minus T + 4	r	0.898*
	p	0.002

Notes: T + 1: 10–25 minutes after the start of opioid medication; T + 4: 10–135 minutes after the start of opioid medication; T − 1: 15 minutes before the start of opioid medication; T + 2: 10–45 minutes after the start of opioid medication; T + 3: 10–75 minutes after the start of opioid medication.

Abbreviations: LF, low frequency; HF, high frequency.