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Analysis of F-wave parameters in normal infants and children
Ahmed S M Nadeem1, Dahfir I El-Yassin, Fakir Al-Ani
1Department of Physiology, College of Medicine, Baghdad University, Baghdad, Iraq.
Insights
F-wave latency in Iraqi children shows developmental changes, with minimal latency decreasing initially then increasing. F-chronodispersion reveals differing maturation rates between fast and slow nerve fibers during the first year of life.
Area of Science:
- Neurology
- Pediatric Neurology
- Neurophysiology
Background:
- F-wave is a late electrophysiological response following direct muscle response after supramaximal nerve stimulation.
- Understanding F-wave parameters is crucial for assessing nerve development and maturation.
Purpose of the Study:
- To investigate developmental changes in F-wave parameters in normal Iraqi children under 12 years old.
- To evaluate maturation of the proximal ulnar nerve segment using F-wave analysis.
Main Methods:
- 167 healthy Iraqi children under 12 years were studied.
- F-waves were recorded from the abductor digiti minimi muscle by stimulating the ulnar nerve at the wrist.
- Key parameters analyzed included minimal latency, maximal latency, and F-chronodispersion.
Main Results:
- Mean F-wave minimal latency was constant in infants <6 months, decreased in 6-9 months, then increased linearly with age.
- Mean F-wave maximal latency showed no significant change in the first year, then increased with age.
- Latency changes are attributed to nerve maturation (myelination, diameter) and limb growth.
Conclusions:
- Iraqi children exhibit lower mean F-wave minimal latency than Western children, likely due to height differences.
- Age-related changes in F-minimal and F-maximal latency reflect varying maturation rates of different nerve fibers.
- F-chronodispersion indicated faster maturation in the fastest nerve fibers during the first year, with slower fibers maturing more gradually thereafter.
Background:
F-wave is a late response evoked by supramaximal stimulation to the nerve and occurring after direct muscle response.
Subjects And Methods:
F-wave parameters were investigated in 167 normal Iraqi children, who were all below the age of 12 years. F-waves which were recorded from the abductor digiti minimi by stimulation of the ulnar nerve at the wrist were evaluated to assess developmental changes in the proximal segment of the nerve.
Results:
The mean F-wave minimal latency value remained constant in the various age groups during the first 6 months of life, then it was reduced in the next 6-<9 months age group. After that, it increased linearly in the successive age groups, while the mean F-wave maximal latency values remained without statistical changes in the age groups during the first year of life but increased with age afterwards. Two simultaneous processes: a rapid increase in conduction velocity due to maturation (increase in nerve fiber diameter and in myelination) and an increase in upper limb length due to growth were responsible for these latency changes.
Conclusion:
F-wave minimal latency for the ulnar nerve have lower mean values in Iraqi children than in Western children due to height differences. Differences in the pattern of F-minimal and F-maximal latency changes with age reflect different rates of maturation in the different nerve fibers. F-chronodispersion (the difference between the F-maximal and F-minimal latencies) was used as a sensitive method to assess the variability between the changes affecting the fastest and the slowest proximal nerve fibers contributing to F-wave formation. The mean F-chronodispersion values were found to increase during the first year of life and reduce afterwards. This shows that the fastest conducting nerve fibers have more rapid and prominent changes than the slowest ones during the first year of life, after which the slowest conducting nerve fibers seem to have more gradual maturational changes than the fastest ones.
