title: Sensory and motor thresholds of transcutaneous electrical stimulation are influenced by gender and age.
abstract: BACKGROUND
  Transcutaneous electrical stimulation (ES) is a therapeutic procedure used in rehabilitation. However, the effectiveness of it depends on sensory responses to pain and motor control in neuromuscular recruitment, considering the differences related to gender and age of the subjects treated, as well as the intensity and frequency of ES.
  
  
  OBJECTIVE
  To determine the threshold of sensory perception (TSP) and the threshold of motor response (TMR) in young and elderly individuals of both genders.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  General community.
  
  
  METHODS
  Eighty volunteers with no history of systemic diseases were selected to participate in the study: 40 men and 40 women were subdivided by convenience sampling and age group into young male and female (age 21.6 ± 2.4 years) groups as well as into elderly female and male groups (age 72.6 ± 6.1 years).
  
  
  METHODS
  The participants received electrical stimulation (ES) at 5 and 50 Hz, with pulse durations of 20, 100, 400, 1000, and 3000 μs applied on the flexor muscle bellies of the wrist and fingers.
  
  
  METHODS
  TSP was identified as the first sensation of increased current intensity and TMR as the minimum muscle contraction detected. The results were submitted to analysis of variance, followed by the Tukey's test, with a significance level of 5%.
  
  
  RESULTS
  TSP was lower than TMR for all pulse durations, regardless of gender and age. In women, TSP was lower than that in young and elderly men at both frequencies. However, TSP was higher in elderly subjects than in younger subjects at 50 Hz for both genders. Age also affected the TMR, presenting higher thresholds in elderly subjects of both genders at 50 Hz; however the same occurred only in male subjects at 5 Hz.
  
  
  CONCLUSIONS
  Age and gender interfere directly with ES. These variables should be considered during rehabilitation because they indicate that electrical stimulation in elderly women should be carefully performed, as they have lower thresholds than elderly men when polarized currents are used, and there is a risk of skin lesion because of their high thresholds.
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil; and Post-Graduation Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil(∗). Electronic address: rguirro@fmrp.usp.br.
authors.forename: Rinaldo Roberto de Jesus
authors.initials: RR
authors.lastname: Guirro
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil; and Post-Graduation Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil(†).
authors.forename: Elaine Caldeira de Oliveira
authors.initials: EC
authors.lastname: Guirro
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation and post-graduate program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil(‡).
authors.forename: Natanael Teixeira Alves
authors.initials: NT
authors.lastname: de Sousa
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology / Q000534:rehabilitation*; D017288:Pain Threshold / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology*; D012737:Sex Factors; D055815:Young Adult