Due to the phenomenon of ageing population, cognitive impairment has become more prevalent, and any marker able to improve its detection becomes of significant importance. With that objective in mind, a prospective observational study was performed in a medical consultation related to cognitive impairment. 150 subjects (58% women) were included with an average age of 76 years (SD 8.6). The Head Turn sign was positive for 32 subjects with a sensitivity of 41.7% for dementia, a specificity of 93.7% and a negative predictive value of 64.4%. This study shows the semiologic value of a simple clinical sign, easy to spot in the daily practice and most helpful to alert physicians about a likely dementia diagnosis.