Cold face test in persons with spinal cord injury: age versus inactivity.
BACKGROUND
Persons with spinal cord injury (SCI) reflect a model of precocious aging and inactivity; as such, these individuals manifest well-appreciated cardiovascular abnormalities. We aimed to determine the influence of inactivity in persons with SCI, and the influence of age in healthy controls, on cardiovascular autonomic responses to the cold face test (CFT).


METHODS
Subjects recruited (n = 42) included 18 controls: 10 young (25 +/- 2 years) and 8 old (50 +/- 6 years), and 24 subjects with chronic SCI: 17 with tetraplegia (C3-C8 44 +/- 7 years) and 7 with paraplegia (T5-T10 36 +/- 8 years). Heart rate (HR) and blood pressure were collected continuously: 2-min pre-CFT, 1-min CFT and 2-min post-CFT. Time-frequency (wavelet) analysis of HR (HFln) was used as an estimate of vagal cardiac modulation.


RESULTS
The HR response to the CFT differed significantly among the SCI group (4.1 +/- 8.8 bpm) and the young (-7.7 +/- 5.9 bpm; P \ 0.001) and old (-6.8 +/- 10.7 bpm; P \ 0.01). The HFln response was reduced in the SCI (0.01 +/- 1.59) as compared with the young controls (1.50 +/- 1.50; P \ 0.05), but was not different from the old controls (0.69 +/- 1.39). The bradycardia did not differ among the young and old controls; however, the vagal response was attenuated in the old compared with the young. These data suggest that age does not significantly alter the heart rate response to the CFT, but attenuates the vagal response.


CONCLUSIONS
In the SCI group, the paradoxical heart rate response to facial cooling and the lack of vagal activation suggest that abnormal autonomic cardiovascular reflexive control may result from profound inactivity and/or from the spinal cord injury per se.
Rehabilitation Research and Development Center of Excellence for the Medical Consequences of Spinal Cord Injury, The James J. Peters VA Medical Center, Bronx, NY 10468, USA. jm.wecht@va.gov
Jill M
JM
Wecht
Joseph P
JP
Weir
Ronald E
RE
DeMeersman
Gregory J
GJ
Schilero
John P
JP
Handrakis
Michael F
MF
LaFountaine
Christopher M
CM
Cirnigliaro
Steven C
SC
Kirshblum
William A
WA
Bauman
D000328:Adult; D000367:Age Factors; D001794:Blood Pressure / Q000502:physiology*; D001919:Bradycardia / Q000503:physiopathology*; D018376:Cardiovascular Abnormalities / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D005145:Face / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D014630:Vagus Nerve / Q000503:physiopathology*; D055536:Vagus Nerve Stimulation; D055815:Young Adult