Movement characteristics of human spermatozoa analysed from kinemicrographs

Abstract

Motility characteristics of human spermatozoa have been analysed by modern research film methods and compared with visual motility ratings. Spatial distributions and fluctuations of sperm numbers in small subfields deviated significantly from the expected Poisson distribution. Agreement between visual motility estimations and measurements was poor (r = 0.76, explaining only 57% of the variance) with large scatter, whereas there was no difference between highly experienced observers and greenhorns. It is concluded that improvement of visual estimation results by standardisation, training and experience is no attainable goal. There was a significant influence of the sample image on the visual ratings of all observers. Three main groups of tracks can be distinguished: Type I: normal, mainly progressive movement with nearly rectilinear resultant and small lateral head displacements; Type 2: mainly progressive movement, resultant rectilinear or the projection of a helix; sometimes irregular changes of direction; generally large lateral head displacements; Type 3: mainly yawing, circular and helical tracks (pathological movements resulting from impaired midpiece function). In the combined Types 2+3 visual motility ratings are significantly influenced by the mean velocity of the spermatozoa. It is generally concluded that visual motility estimations should be totally abandoned and replaced by objective measuring methods. Where no photoelectrical and electronical methods are available three alternative simple quantitative methods are advocated.