Tracking down the White Plague. Chapter three: Revision of endocranial abnormally pronounced digital impressions as paleopathological diagnostic criteria for tuberculous meningitis

Abnormally pronounced digital impressions (APDIs) on the endocranial surface develop secondary to a prolonged rise in the intracranial pressure. This can result from a number of pathological conditions, including hydrocephalus due to tuberculous meningitis (TBM). APDIs have been described with relation to TBM not only in the modern medical literature but also in several paleopathological studies. However, APDIs are not pathognomonic for TBM and their diagnostic value for identifying TBM in past human populations has not been evaluated in identified pre-antibiotic era skeletons. To assess the diagnostic value of APDIs for the first time, a macroscopic investigation was performed on skeletons from the Terry Collection (Smithsonian Institution, Washington, DC, USA). Our material consisted of 234 skeletons with tuberculosis (TB) as the cause of death (TB group) and 193 skeletons with non-tuberculous (NTB) causes of death (NTB group). The macroscopic examination focused on the stage of the prominence and frequency of APDIs in the TB group and NTB group. To determine the significance of difference (if any) in the frequency of APDIs between the two groups, χ2 testing of our data was conducted. We found that APDIs were twice as common in the TB group than in the NTB group. The χ2 comparison of the frequencies of APDIs revealed a statistically significant difference between the two groups. In addition, APDIs with more pronounced stages were recorded more frequently in the TB group. Our results indicate that APDIs can be considered as diagnostic criteria for TBM in the paleopathological practice. With suitable circumspection, their utilization provides paleopathologists with a stronger basis for identifying TB and consequently, with a more sensitive means of assessing TB frequency in past human populations.

Fourier Analysis of Human Sagittal Sutures

Objective: To evaluate the complexity of human sagittal suture patterns and to investigate whether the suture complexity correlates with age. Design: Geometric patterns of the sagittal sutures from 104 dry human skulls from the Terry Collection and 16 computed tomography images from the Bosma Collection, aged 2 months to 60 years, were digitized. The complexity of the patterns was presented by suture length, curved suture (or skull) length, and length ratio and the frequency and amplitude contents by the discrete Fourier transform (DFT) analysis. Results: The suture length along the skull showed a positive correlation with age from 2 months to 10 years, reflecting the growth of the skull. The suture length ratio, R, a measure of the complexity of the suture pattern, had a similar trend to suture length (i.e., increased with age to about 10 years and leveled off afterward, accompanied by a large scatter). The major frequency from the DFT analysis indicated an age-related development in suture complexity from infants to about 10 years and no further change for individuals older than 10 years. Conclusions: Quantitative analyses of human sagittal suture using length, length ratio, and DFT indicated that there is a progressive increase in the complexity of sagittal sutural waveform with age, especially in the early ages. These findings agree with the observations from animal experiments that sagittal sutural waveform is the result of intrinsic tissue response to extrinsic forces such as those generated by the temporalis.