Insights into the diagnostic efficacy and macroscopic appearance of endocranial bony changes indicative of tuberculous meningitis: Three example cases from the Robert J. Terry Anatomical Skeletal Collection

Recently, the combined macroscopic and statistical evaluation of 427 identified pre-antibiotic era skeletons from the Terry Collection (Washington, DC, USA) revealed that there is a positive association between tuberculous meningitis (TBM) and four endocranial alteration types, namely, granular impressions (GIs), abnormal blood vessel impressions (ABVIs), periosteal appositions (PAs), and abnormally pronounced digital impressions (APDIs). Although all the four lesion types can be used as diagnostic criteria for TBM in the paleopathological practice, they do not have the same diagnostic value. The first aim of the current paper is to further highlight the diagnostic value of GIs, ABVIs, PAs, and APDIs by calculating and discussing their diagnostic sensitivity and specificity estimate values, as well as their association with each other from the 427 identified pre-antibiotic era skeletons of the Terry Collection. The second aim is to demonstrate three example cases from the Terry Collection, who exhibit bony changes on the inner skull surface that are representative of the macromorphological appearance and co-occurrence of GIs, ABVIs, PAs, and APDIs (in different combinations). Based on the generated sensitivity and specificity estimate values, GIs are sufficient enough on their own to make a definitive diagnosis of TBM, whereas ABVIs, PAs, and APDIs are not specific to the disease but can be of tuberculous origin. The chi(2) test results regarding the association of ABVIs, PAs, and APDIs revealed that their co-occurrence with each other (in any possible combination) is significantly more common in individuals who died of TB than in those who died of non-TB causes-it implies that the chance of them being tuberculous in origin is higher when they simultaneously occur with each other. The three cases demonstrated in detail in the paper provide paleopathologists with a stronger basis for identifying TBM in ancient human remains that reveal endocranial alterations resembling that of the presented cases.