Generational Changes in Lumbar Spinal Canal Dimensions: Findings from a Sample U.S. Population.

OBJECTIVE: Evaluation of lumbar canal dimensions in a Chicago population born in 2 different decades. METHODS: This is a retrospective chart review analyzing computed tomography reconstruction from patients born between 1940 and 1949 (older group) and 1970 and 1979 (younger group). The cross-sectional area (CSA) and anterior-posterior diameter (APD) of the lumbar bony canal was measured at each lumbar level at the level of the pedicle. RESULTS: Our study includes 918 patients, 372 in the young group and 546 in the older group. Older patients have significantly larger CSA and APD at all lumbar levels compared with younger patients. Further, CSA and APD comparisons between ethnicities demonstrate significant differences between individuals of Caucasian, Asian, Hispanic, African American, and Other ethnicities. Lastly, there were no differences in CSA or APD compared with factors known to affect bone health (smoking, steroid use, osteoporosis, cancer history). CONCLUSIONS: As seen in European cohorts, our data suggest that patients born in the 1940s have both larger canal area and larger anterior-posterior diameter compared with the younger generation. These data suggest that significant differences exist between ethnicities. These differences highlight the importance of studying normal anatomical dimensions within different geographical populations and the importance of studying non-modifiable factors as they relate to spinal dimensions and spine patients. Furthermore, spinal canal growth seems to be negatively influenced in younger generations, a rather unexpected but worrying finding.

Traumatic brain injury among female veterans: a review of sex differences in military neurosurgery.

The impact of traumatic brain injury (TBI) has been demonstrated in various studies with respect to prevalence, morbidity, and mortality data. Many of the patients burdened with long-term sequelae of TBI are veterans. Although fewer in number, female veterans with TBI have been suggested to suffer from unique physical, mental, and social challenges. However, there remains a significant knowledge gap in the sex differences in TBI. Increased female representation in the military heralds an increased risk of TBI for female soldiers, and medical professionals must be prepared to address the unique health challenges in the face of changing demographics among the veteran TBI population. In this review, the authors aimed to present the current understanding of sex differences in TBI in the veteran population and suggest directions for future investigations.

Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging.

UNLABELLED: Decline in cognitive skills, especially in memory, is often viewed as part of "normal" aging. Yet some individuals "age better" than others. Building on prior research showing that cortical thickness in one brain region, the anterior midcingulate cortex, is preserved in older adults with memory performance abilities equal to or better than those of people 20-30 years younger (i.e., "superagers"), we examined the structural integrity of two large-scale intrinsic brain networks in superaging: the default mode network, typically engaged during memory encoding and retrieval tasks, and the salience network, typically engaged during attention, motivation, and executive function tasks. We predicted that superagers would have preserved cortical thickness in critical nodes in these networks. We defined superagers (60-80 years old) based on their performance compared to young adults (18-32 years old) on the California Verbal Learning Test Long Delay Free Recall test. We found regions within the networks of interest where the cerebral cortex of superagers was thicker than that of typical older adults, and where superagers were anatomically indistinguishable from young adults; hippocampal volume was also preserved in superagers. Within the full group of older adults, thickness of a number of regions, including the anterior temporal cortex, rostral medial prefrontal cortex, and anterior midcingulate cortex, correlated with memory performance, as did the volume of the hippocampus. These results indicate older adults with youthful memory abilities have youthful brain regions in key paralimbic and limbic nodes of the default mode and salience networks that support attentional, executive, and mnemonic processes subserving memory function. SIGNIFICANCE STATEMENT: Memory performance typically declines with age, as does cortical structural integrity, yet some older adults maintain youthful memory. We tested the hypothesis that superagers (older individuals with youthful memory performance) would exhibit preserved neuroanatomy in key brain networks subserving memory. We found that superagers not only perform similarly to young adults on memory testing, they also do not show the typical patterns of brain atrophy in certain regions. These regions are contained largely within two major intrinsic brain networks: the default mode network, implicated in memory encoding, storage, and retrieval, and the salience network, associated with attention and executive processes involved in encoding and retrieval. Preserved neuroanatomical integrity in these networks is associated with better memory performance among older adults.