Intra-individual variation of sperm velocity, linearity, lateral head displacement and beat frequency in healthy volunteers.

In an effort to evaluate the intra-individual fluctuations of sperm motion parameters 12 healthy young men with normal semen parameters were recruited. Weekly semen analysis was performed for 13 weeks. Conventional semen parameters such as sperm concentration, percentage of motile and normally formed sperm were determined according to WHO guidelines, while sperm velocity, linearity, lateral head displacement and beat frequency were evaluated by computerized image analysis. Mean and standard deviations (SD) of all parameters were computed for each individual. Coefficients of variation were expressed as the ratio of SD/mean. On average the following coefficients of variation were found: total number of sperm 58 (+/- 5%); concentration of sperm 47 (+/- 4%); lateral head displacement 27 (+/- 4%); volume 24 (+/- 3%); velocity 19 (+/- 2%); linearity 17 (+/- 2%); percentage of motile sperm 12 (+/- 2%); beat frequency: 12 (+/- 2%) and percentage of normally formed sperm 9 (+/- 1%). The low variation of sperm motion parameters and the ease of their determination suggests that computerized motion analysis of sperm may be a valuable research tool to detect subtle effects e.g. of drugs and environmental toxins on reproductive functions in men.