BACKGROUND: Studies suggest that the pain response may be evaluated using pupillometry and is influenced by factors such as gender and anxiety. OBJECTIVES: The aim of this study was to use pupillometry to observe the effects of gender and anxiety on the pain response. STUDY DESIGN: A randomized, prospective, clinical and interventional study. SETTING: Center for Research on Pain at the Federal University of Maranhao, Brazil. METHODS:Ninety-six patients were divided into groups according to their level of anxiety as indicated by the Beck questionnaire. Under photopic conditions and using retinography, these patients underwent pupillometry while a painful pressure stimulus of 1,500 kPa was applied to the middle phalanx of each patient's right middle finger using a pressure algometer. RESULTS: The pupil diameter increased in response to pain in all study participants, regardless of gender and anxiety level; the average pupil diameter was 3.265 ± 0.028 mm before the painful stimulus and 4.31 ± 0.200 mm for the duration of the stimulus (P = 0.0251). There was no significant difference between the genders in the level of anxiety (P = 0.614). Regardless of gender, individuals with moderate to severe anxiety had higher average pupil diameters than individuals exhibiting mild or no anxiety (P = 0.019). Men had a higher average pupil diameter than women (4.53 ± 0.345 mm and 4.48 ± 0.358 mm, respectively); however, this difference was not statistically significant in the presence of moderate to severe anxiety (P = 0.072). LIMITATIONS: The number of men with high anxiety was insufficient to create their own group. CONCLUSIONS: The pupil dilation in response to a painful stimulus was similar in both genders. Additionally, regardless of gender, the average pupil diameter was greater in the presence of moderate to severe anxiety.
RCT Entities:
BACKGROUND: Studies suggest that the pain response may be evaluated using pupillometry and is influenced by factors such as gender and anxiety. OBJECTIVES: The aim of this study was to use pupillometry to observe the effects of gender and anxiety on the pain response. STUDY DESIGN: A randomized, prospective, clinical and interventional study. SETTING: Center for Research on Pain at the Federal University of Maranhao, Brazil. METHODS: Ninety-six patients were divided into groups according to their level of anxiety as indicated by the Beck questionnaire. Under photopic conditions and using retinography, these patients underwent pupillometry while a painful pressure stimulus of 1,500 kPa was applied to the middle phalanx of each patient's right middle finger using a pressure algometer. RESULTS: The pupil diameter increased in response to pain in all study participants, regardless of gender and anxiety level; the average pupil diameter was 3.265 ± 0.028 mm before the painful stimulus and 4.31 ± 0.200 mm for the duration of the stimulus (P = 0.0251). There was no significant difference between the genders in the level of anxiety (P = 0.614). Regardless of gender, individuals with moderate to severe anxiety had higher average pupil diameters than individuals exhibiting mild or no anxiety (P = 0.019). Men had a higher average pupil diameter than women (4.53 ± 0.345 mm and 4.48 ± 0.358 mm, respectively); however, this difference was not statistically significant in the presence of moderate to severe anxiety (P = 0.072). LIMITATIONS: The number of men with high anxiety was insufficient to create their own group. CONCLUSIONS: The pupil dilation in response to a painful stimulus was similar in both genders. Additionally, regardless of gender, the average pupil diameter was greater in the presence of moderate to severe anxiety.
Authors: Andrew R Mitz; Ravi V Chacko; Philip T Putnam; Peter H Rudebeck; Elisabeth A Murray Journal: J Neurosci Methods Date: 2017-01-13 Impact factor: 2.390
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