Ear infection prevalence in prehistoric and historic populations of the southern Levant: A new diagnostic method

Studying infectious diseases in ancient times is of significant importance to our understanding of past populations' ways of life. Otitis media (OM) is beneficial for this purpose because it is frequent and influenced by environmental conditions. The aims of the current study were to create a reliable criterion for identifying OM in skeletal material, and to follow trends regarding the prevalence of OM throughout the terminal Pleistocene–Holocene Levant. Complete petrous bones of 229 individuals from six populations of the terminal Pleistocene–Holocene Levant (14,900 cal bp–1,917 ad) were included in the study. The promontory of the middle ear was examined using a flexible videoscope and a microscope. The observations were validated by micro-computed tomography (CT) images. The absence or presence of bone remodelling on the promontory surface was registered as well as the appearance of the promontory sulcus (open or covered). Kappa tests were carried out to examine intra- and inter-observer variation. Chi-squared tests were carried out to examine the association between promontory appearance and period as well as the association between the presence of bone remodelling and the sulcus type. The suggested criteria were found to be reliable. A fluctuation in the prevalence of bone remodelling on the promontory surface was found during the studied period. The highest prevalence (80%) was among the protohistoric populations, followed by the prehistoric populations (~60.6%), and finally, the historic populations (~50.4%). The types of promontory sulcus remained relatively stable during the studied period. Moreover, no significant association was found between the presence of bone remodelling on the promontory surface and the sulcus type. To conclude, bone remodelling on the promontory surface is a new, simple, and reliable method to identify OM in skeletal material. However, promontory sulcus type is most likely not associated with OM. The fluctuations in OM prevalence during the Holocene Levant were probably due to habitation type and climate conditions.