Effects of sex and age on strength–duration properties

• Published in: Clinical neurophysiology Vol. 117; no. 9; pp. 2069 - 2072
• Main Authors: Yerdelen, Deniz, Uysal, Hilmi, Koc, Filiz, Sarica, Yakup
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.09.2006; Elsevier Science
• Subjects: Action Potentials - physiology; Action Potentials - radiation effects; Adolescent; Adult; Age; Aged; Aged, 80 and over; Aging - physiology; Axonal excitability; Biological and medical sciences; Dose-Response Relationship, Radiation; Electric Stimulation - methods; Electrodiagnosis. Electric activity recording; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Median Nerve - physiology; Medical sciences; Middle Aged; Nervous system; Nervous system (semeiology, syndromes); Nervous system as a whole; Neural Conduction - physiology; Neural Conduction - radiation effects; Neurology; Reaction Time - physiology; Reaction Time - radiation effects; Sex; Sex Characteristics; Threshold; Wrist - innervation; Wrist - physiology; Axonal excitability; Age; Sex; Threshold; Human; Excitability; Ionic channel; Wrist; Electrodiagnosis; Sodium; Median nerve; Membrane; Time constant; Strength
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2006.05.016

To evaluate the possible effects of sex and age on strength–duration time constant (SDTC). The SDTC of 126 healthy volunteers was measured following stimulation of right median nerve at the wrist. Variations in values were evaluated according to sex and age. The SDTC was 438.6 ± 114.5 μs in women and 396.2 ± 90.3 in men ( P = .023). In men, as age increased, so did SDTC. However, this was not true in women. Comparing the values of women and men, aged below 40, demonstrated a difference in excitability, confined to younger patients. As SDTC depends on the biophysical properties of the axonal membrane and can provide some information about Na + channel function, these data raise the possibility of a difference in Na + channel function between men and women and a difference in the conductance with age. The age- and sex-related differences shown in this study suggest a possible biochemical or hormonal influence on axonal excitability.