1. Lowering of Sensory, Motor, and Pain-Tolerance Thresholds With Burst Duration Using Kilohertz-Frequency Alternating Current Electric Stimulation: Part II 
Alex R. Ward, PhD, Wendy Lee Hung Chuen, BSc(Hons) 
Archives of Physical Medicine and Rehabilitation 
Volume 90, Issue 9, Pages (September 2009)
DOI: /j.apmr
Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

2. Fig 1
Stimulus types commonly used in rehabilitation. (A) Biphasic pulsed current. (B) Monophasic pulsed current. (C) Bursts of AC with a duty cycle of 50%. (D) Bursts of AC typical of interferential current.
Archives of Physical Medicine and Rehabilitation  , DOI: ( /j.apmr )
Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

3. Fig 2
Sensory threshold versus burst duration at: (A) 1kHz and (B) 4kHz; (C) 1-kHz and (D) 4-kHz motor thresholds; (E) 1-kHz and (F) 4-kHz pain-tolerance thresholds. (⧫) are values in volts (V), measured at a burst frequency of 20Hz, and (⊡) are values at 50Hz previously reported by Ward and Lucas-Toumbourou.19
Archives of Physical Medicine and Rehabilitation  , DOI: ( /j.apmr )
Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

4. Fig 3
Relative thresholds at different burst durations with burst frequencies of 50Hz (⊡) and 20Hz (⧫). (A) Pain/motor thresholds using bursts of 1-kHz AC. (B) Pain/motor thresholds using bursts of 4-kHz AC. 50-Hz relative thresholds were previously reported by Ward and Lucas-Toumbourou.19
Archives of Physical Medicine and Rehabilitation  , DOI: ( /j.apmr )
Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

5. Fig 4
Relative thresholds at different burst durations with burst frequencies of 50Hz (⊡) and 20Hz (⧫). (A) Pain/sensory thresholds using bursts of 1-kHz AC. (B) Pain/sensory thresholds using bursts of 4-kHz AC. 50-Hz relative thresholds were previously reported by Ward and Lucas-Toumbourou.19
Archives of Physical Medicine and Rehabilitation  , DOI: ( /j.apmr )
Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions