Handwriting changes under the effect of alcohol

Document examiners are often faced with difficulties in evaluating handwriting by persons under the influence of alcohol. Although numerous articles are available on the subject of alcohol influence on handwriting quality, most of them were based on empirical data such as "few" or "increased", without any statistical evaluation. The aim of this research is to determine whether previous observations on reported effects of alcohol on handwriting are valid and to establish the predictability of observing specific effects. A total of 73 participants, who completed all steps of the experiment, were surveyed. Handwriting samples were taken before and after the consumption of alcohol. The test form, including criteria of prior studies used by document examiners, was evaluated with the help of a Olympus X-Tr stereo microscope, direct and oblique angle lighting and a video spectral comparator (VSC 2000). Measurements were done by means of digital caliper, statistics using repeated measures ANOVA, Pearson correlation, Pearson Chi square test, McNemar test and Wilcoxon signed rank test.The results revealed that the handwriting parameters such as word lengths, height of upper and lower case letters, height of ascending letter, height of descending letter, spacing between words, number of angularity, number of tremor, and number of tapered ends are all significantly increased under the effect of alcohol.It was also determined that the significant correlation between the alteration of handwriting parameters such as height of upper and lower case letters, number of angularity, number of tapered ends and the amount of alcohol. Furthermore, it does not confirm the conclusions of previous studies stating that alcohol levels are not proper indicators. Our data strongly confirms that handwriting changes can be observed at any level of alcohol.None of the alterations in handwriting can be attributed to the effects of alcohol intake alone. However, the presence of some alterations together is strongly suggestive that the person was under the influence of alcohol.First of all, the duty of handwriting examiner is to identify if the questioned and known sample are coming from the same source. Consequently, as this explanatory analysis suggests that differences between sober and intoxicated persons can be identified in handwriting, but the examiner's judgement must be proportionately cautious, keeping in mind the abnormally wide range of variation.