Relationship of Morphometrics and Symptom Severity in Female Type I Chiari Malformation Patients with Biological Resilience.

In the present study we report the relationship among MRI-based skull and cervical spine morphometric measures as well as symptom severity (disability-as measured by Oswestry Head and Neck Pain Scale and social isolation-as measured by the UCLA Loneliness scale) on biomarkers of allostatic load using estrogen, interleukin-6, C-reactive protein, and cortisol in a sample of 46 CMI patients. Correlational analyses showed that McRae line length was negatively associated with interleukin-6 and C-reactive protein levels, and Analysis of Variance (ANOVA) showed joint effects of morphometric measures (McRae line length, anterior CSF space) and symptom severity (disability and loneliness) on estrogen and intereukin-6 levels. These results are consistent with allostatic load. That is, when the combination of CSF crowding and self-report symptom (disability and loneliness) severity exceed the capacity of biological resilience factors, then biomarkers such as neuroprotective estrogen levels drop, rather than rise, with increasing symptom severity.

Adult Age Differences in Self-Reported Pain and Anterior CSF Space in Chiari Malformation.

Chiari malformation type I (CMI) is a neural disorder with sensory, cognitive, and motor defects, as well as headaches. Radiologically, the cerebellar tonsils extend below the foramen magnum. To date, the relationships among adult age, brain morphometry, surgical status, and symptom severity in CMI are unknown. The objective of this study was to better understand the relationships among these variables using causal modeling techniques. Adult CMI patients (80% female) who either had (n = 150) or had not (n = 151) undergone posterior fossa decompression surgery were assessed using morphometric measures derived from magnetic resonance images (MRI). MRI-based morphometry showed that the area of the CSF pocket anterior to the cervico-medullary junction (anterior CSF space) correlated with age at the time of MRI (r = - .21). Also, self-reported pain increased with age (r = .11) and decreased with anterior CSF space (r = - .18). Age differences in self-reported pain were mediated by anterior CSF space in the cervical spine area-and this effect was particularly salient for non-decompressed CMI patients. As CMI patients age, the anterior CSF space decreases, and this is associated with increased pain-especially for non-decompressed CMI patients. It is recommended that further consideration of age-related decreases in anterior CSF space in CMI patients be given in future research.

Influence of Pain on Cognitive Dysfunction and Emotion Dysregulation in Chiari Malformation Type I.

It has been well demonstrated that the cerebellum is associated with cognitive and affective processing as well as the traditionally conceptualized motor function. In the present chapter, we explore the behavioral and neurobiological implications of a common congenital cerebellar condition, Chiari malformation Type I, on cognitive and affective processing. We also emphasize the associations between Chiari-related chronic pain, cognitive dysfunction, and emotion dysregulation. Based on our review of the literature, we argue that chronic pain can account for a substantial amount of the cognitive dysfunction and emotion dysregulation in Chiari malformation Type I. Yet, there also exists aspects of Chiari-related cognitive dysfunction and emotion dysregulation that appear to be at least partially independent of chronic pain and more directly associated with abnormalities in cerebrospinal fluid flow dynamics and cerebro-cerebellar communication pathways.

Impact of Surgical Status, Loneliness, and Disability on Interleukin 6, C-Reactive Protein, Cortisol, and Estrogen in Females with Symptomatic Type I Chiari Malformation.

Chiari malformation type I (CMI) provides an opportunity for examining possible moderators of allostatic load. CMI patients who had (n = 43) and had not (n = 19) undergone decompression surgery completed questionnaires regarding pain, disability, and loneliness, and provided serum samples for IL-6, CRP, estrogen, and free estradiol assays, and saliva samples to assess diurnal cortisol curves. ANOVAs examining surgical status (decompressed versus non-decompressed), loneliness (high vs. low), and disability (high vs. low) as independent variables and biomarker variables as dependent factors found that loneliness was associated with higher levels of cortisol, F(1, 37) = 4.91, p = .04, η2P = .11, and lower levels of estrogen, F(1, 36) = 7.29, p = .01, η2P = .17, but only in decompressed patients. Results highlight the possible impact of loneliness on biological stress responses and the need to intervene to reduce loneliness in patients with symptomatic CMI.

An Electrophysiological Study of Aging and Perceptual Letter-Matching.

Background: Previous studies on perceptual letter-matching have found that younger and older adults showed "fast-same" effects for response time and "false-different" effects for errors but the effects were more pronounced for older adults. According to the Noisy Operator Theory, internal noise in visual processing distorts "same" trials into appearing different whereas distortion for "different" trials does not affect performance. Older adults have a "noisier" representation of items within perceptual processing which can impact perceptual matching. However, EEG measures may provide a more direct measure of letter-matching decisions. Methods: We measured the P300 event-related potential (ERP) amplitude, an index of familiarity in stimulus categorization, and behavioral measures (response time and accuracy) to assess letter-matching performance. Results: Individuals responded faster to "same" trials than to "different" trials but were less accurate. Older adults showed similar P300 amplitudes across trial type whereas younger adults produced a larger amplitude for "same" than "different" trials, suggesting that older adults showed less familiarity for "same" trials than did younger adults - a prediction of the Noisy Operator Theory. Conclusions: These ERP results are consistent with the Noisy Operator Theory - suggesting that an age-related increase in internal noise affected letter-matching performance.

Is the AO spine thoracolumbar injury classification system reliable and practical? a systematic review.

Controversy surrounding the classification of thoracolumbar injuries has given rise to various classification systems over the years, including the most recent AOSpine Thoracolumbar Injury Classification System (ATLICS). This systematic review aims to provide an up-to-date evaluation of the literature, including assessment of a further three studies not analysed in previous reviews. In doing so, this is the first systematic review to include the reliability among non-spine subspecialty professionals and to document the wide variety between reliability across studies, particularly with regard to sub-type classification. Relevant studies were found via a systematic search of PubMed, EBESCO, Cochrane and Web of Science. Data extraction and quality assessment were conducted in line with Cochrane Collaboration guidelines. Twelve articles assessing the reliability of ATLICS were included in this review. The overall inter-observer reliability varied from fair to substantial, but the three additional studies in this review, compared to previous reviews, presented on average only fair reliability. The greatest variation of results was seen in A1 and B3 subtypes. Least reliably classified on average was A4 subtype. This systematic review concludes that ATLICS is reliable for the majority of injuries, but the variability within subtypes suggests the need for further research in assessing the needs of users in order to increase familiarity with ATLICS or perhaps the necessity to include more subtype-specific criteria into the system. Further research is also recommended on the reliability of modifiers, neurological classification and the application of ATLICS in a paediatric context.

A comparison of anterior knee pain, kneeling pain and functional outcomes in suprapatellar versus infrapatellar tibial nailing.

INTRODUCTION: Anterior knee pain and kneeling pain are some of the most common complications following intramedullary nailing of tibial shaft fractures. With the increased uptake of suprapatellar nailing at our institution, we undertook a service evaluation to assess anterior knee pain and kneeling pain in patients who underwent the suprapatellar tibial nailing technique compared with the infrapatellar approach. METHODOLOGY: Data from all consecutive intramedullary tibial nailing operations between January 2014 and July 2017 were analysed from a prospectively collected database. All acute diaphyseal fracture nailing procedures were included. All patients were reviewed between six-month and four-year post-operation. Each patient was asked to complete a standardised questionnaire with three main outcome measures: pain on kneeling, presence of anterior knee pain and the severity of pain. RESULTS: After exclusions, a total of 148 patients were identified. A total of 102 responses were received, 41 in the infrapatellar group (73.2%) and 61 in the suprapatellar group (66.3%). A longer time from surgery to telephone follow-up response was noted in the infrapatellar group: 32.4 months (interquartile range, 16.1) vs. 19.3 months (interquartile range, 17.4), p < 0.001. A trend towards lower reported anterior knee pain was noted in the suprapatellar group (67.9% VS 53.7%). Most patients reported mild or no pain on kneeling, with no significant difference between the two groups. There was also no significant difference in severity of knee pain between the two groups and no significant effect on the Kujala score. CONCLUSION: With the comparable pain outcomes between the two groups, our analysis supports the continued use of the suprapatellar tibial nailing technique for tibial shaft fractures at our institution.

The use of ionising radiation in orthopaedic surgery: principles, regulations and managing risk to surgeons and patients.

The use of ionising radiation for plain film radiography and computerised tomography is fundamental in both diagnostics and treatment for orthopaedics. However, radiation is not without risk as high exposure can increase the risk of cancer. Little time is spent educating doctors about the relative risks of radiation, both to patients and themselves. In addition, there are common misunderstandings about the best ways to mitigate such risk. We aim to provide an overview of the fundamental principles of the use of ionising radiation and its risks within the context of orthopaedic surgery. While providing a narrative review of the current literature, we discuss the basic physics, standards of good practice and relevant UK and European regulations. We discuss the risks to patients and surgeons and suggest ways that these can be mitigated in the operating theatre. A thorough understanding of the risks, and appropriate procedural rules, with respect to the use of ionising radiation is essential for those in orthopaedic practice.

Persistent hypogammaglobulinemia in pediatric solid organ transplant recipients.

INTRODUCTION: Hypogammaglobulinemia has not been well studied in pediatric solid organ transplant (SOT) recipients. We evaluated plasma immunoglobulin (Ig) and lymphocyte phenotypes among 31 pediatric heart and kidney recipients for two years post-transplant and from 10 non-transplanted children. METHODS: Plasma IgM, IgG, and IgA were quantified by immunoturbidimetric assays, IgG subclasses were quantified by bead-based multiplex immunoassay, and lymphocyte phenotypes were assessed by flow cytometry. RESULTS: Median age at transplant for SOT recipients was similar to that of the control cohort (15 vs. 12.5 years, respectively; P = .61). Mean plasma IgG and IgM levels for SOT recipients fell significantly below the control cohort means by 1 month post-transplant (P < .001 for both) and remained lower than control levels at 12-18 months post-transplant. Heart recipients had lower frequencies of a CD4+ naïve T lymphocytes relative to kidney recipients. CONCLUSIONS: Hypogammaglobulinemia was prevalent and persistent among pediatric SOT recipients and may be secondary to immunosuppressive medications, as well as loss of thymus tissue and CD45RA+   CD4+ T cells in heart recipients. Limitations of our study include but are not limited to small sample size from a single center, lack of samples for all participants at every time point, and lack of peripheral blood mononuclear cell samples for the non-transplanted cohort.

Robust Classification of High-Dimensional Spectroscopy Data Using Deep Learning and Data Synthesis.

This paper presents a new approach to classification of high-dimensional spectroscopy data and demonstrates that it outperforms other current state-of-the art approaches. The specific task we consider is identifying whether samples contain chlorinated solvents or not, based on their Raman spectra. We also examine robustness to classification of outlier samples that are not represented in the training set (negative outliers). A novel application of a locally connected neural network (NN) for the binary classification of spectroscopy data is proposed and demonstrated to yield improved accuracy over traditionally popular algorithms. Additionally, we present the ability to further increase the accuracy of the locally connected NN algorithm through the use of synthetic training spectra, and we investigate the use of autoencoder based one-class classifiers and outlier detectors. Finally, a two-step classification process is presented as an alternative to the binary and one-class classification paradigms. This process combines the locally connected NN classifier, the use of synthetic training data, and an autoencoder based outlier detector to produce a model which is shown to both produce high classification accuracy and be robust in the presence of negative outliers.

Cannabidiol normalizes resting-state functional connectivity in treatment-resistant epilepsy.

OBJECTIVE: Resting-state (rs) network dysfunction is a contributing factor to treatment resistance in epilepsy. In treatment-resistant epilepsy (TRE), pharmacological and nonpharmacological therapies have been shown to improve such dysfunction. In this study, our goal was to prospectively evaluate the effect of highly purified plant-derived cannabidiol (CBD; Epidiolex®) on rs functional magnetic resonance imaging (fMRI) functional connectivity (rs-FC). We hypothesized that CBD would change and potentially normalize the rs-FC in TRE. METHODS: Twenty-two of 27 participants with TRE completed all study procedures including longitudinal pre-/on-CBD rs-fMRI (8M/14F, mean age = 36.2 ±â€¯15.9 years, TRE duration = 18.3 ±â€¯12.6 years); there were no differences in age (p = 0.99) or sex (p = 0.15) between groups. Assessments collected included seizure frequency (SF), Chalfont Seizure Severity Scale (CSSS), Columbia Suicide Severity Rating Scale (C-SSRS), Adverse Events Profile (AEP), and Profile of Mood States (POMS). Twenty-three healthy controls (HCs) received rs-fMRI and POMS once. RESULTS: Participants with TRE showed average decrease of 71.7% in SF (p < 0.0001) and improved CSSS, AEP, and POMS confusion, depression, and fatigue subscores (all p < 0.05) on-CBD with POMS scores becoming similar to those of HCs. Paired t-tests showed significant pre-/on-CBD changes in rs-FC in cerebellum, frontal areas, temporal areas, hippocampus, and amygdala with some of them correlating with improvement in behavioral measures. Significant differences in rs-FC between pre-CBD and HCs were found in cerebellum, frontal, and occipital regions. After controlling for changes in SF with CBD, these differences were no longer present when comparing on-CBD to HCs. SIGNIFICANCE: This study indicates that highly purified CBD modulates and potentially normalizes rs-FC in the epileptic brain. This effect may underlie its efficacy. This study provides Class III evidence for CBD's normalizing effect on rs-FC in TRE.

Clivus length distinguishes between asymptomatic healthy controls and symptomatic adult women with Chiari malformation type I.

PURPOSE: While the presence of cerebellar tonsillar descent in radiological images has been used as evidence of Chiari malformation type I (CMI), tonsillar ectopia alone is insufficient to identify individuals with symptomatic CMI. This study sought to identify differences in brain morphology between symptomatic CMI and healthy controls in adult females. METHODS: Two hundred and ten adult females with symptomatic CMI and 90 age- and body mass index-matched asymptomatic female controls were compared using seven brain morphometric measures visible on magnetic resonance images. The CMI and control groups were divided into four subgroups based on the tonsillar position (TP) relative to the foramen magnum: group 1 was made up of healthy controls with normal TP (TP < 0 mm); group 2 was comprised of control individuals with low-lying TP (1-5 mm); group 3 was comprised of symptomatic CMI patients with low-lying TP (1-5 mm); group 4 contained symptomatic CMI patients with severe tonsillar descent (6-13 mm). RESULTS: All morphometrics for symptomatic CMI with severe tonsillar descent were significantly different than those for both control groups. The CMI group with low-lying TP was significantly different for four measures when compared to controls with normal TP. However, only clivus length was statistically different between the CMI and healthy control groups with low-lying TP. CONCLUSION: This study demonstrates that clivus length distinguishes adult female healthy individuals with low-lying tonsils from those with symptomatic CMI. Further investigation is required to understand the importance of a shorter clivus length on CMI symptomatology and pathophysiology.

Evidence of Neural Microstructure Abnormalities in Type I Chiari Malformation: Associations Among Fiber Tract Integrity, Pain, and Cognitive Dysfunction.

BACKGROUND: Previous case-control investigations of type I Chiari malformation (CMI) have reported cognitive deficits and microstructural white matter abnormalities, as measured by diffusion tensor imaging (DTI). CMI is also typically associated with pain, including occipital headache, but the relationship between pain symptoms and microstructure is not known. METHODS: Eighteen CMI patients and 18 adult age- and education-matched control participants underwent DTI, were tested using digit symbol coding and digit span tasks, and completed a self-report measure of chronic pain. Tissue microstructure indices were used to examine microstructural abnormalities in CMI as compared with healthy controls. Group differences in DTI parameters were then reassessed after controlling for self-reported pain. Finally, DTI parameters were correlated with performance on the digit symbol coding and digit span tasks within each group. RESULTS: CMI patients exhibited greater fractional anisotropy (FA), lower radial diffusivity, and lower mean diffusivity in multiple brain regions compared with controls in diffuse white matter regions. Group differences no longer existed after controlling for self-reported pain. A significant correlation between FA and the Repeatable Battery for the Assessment of Neuropsychological Status coding performance was observed for controls but not for the CMI group. CONCLUSIONS: Diffuse microstructural abnormalities appear to be a feature of CMI, manifesting predominantly as greater FA and less diffusivity on DTI sequences. These white matter changes are associated with the subjective pain experience of CMI patients and may reflect reactivity to neuroinflammatory responses. However, this hypothesis will require further deliberate testing in future studies.

fMRI study of cannabidiol-induced changes in attention control in treatment-resistant epilepsy.

Patients with treatment-resistant epilepsy (TRE) frequently exhibit memory and attention deficits that contribute to their poor personal and societal outcomes. We studied the effects of adjunct treatment with pharmaceutical grade cannabidiol (CBD) oral solution (Epidiolex®; Greenwich Biosciences, Inc.) on attention control processes related to stimulus conflict resolution in patients with TRE. Twenty-two patients with TRE underwent 3 T magnetic resonance imaging (MRI) before receiving (PRE) and after achieving a stable dose of CBD (ON). Functional MRI (fMRI) data were collected while patients performed 2 runs of a flanker task (FT). Patients were instructed to indicate via button press the congruent (CON) and incongruent (INC) conditions. We performed t-tests to examine with FT attention control processes at PRE and ON visits and to compare the 2 visits using derived general linear model (GLM) data (INC - CON). We performed generalized psychophysiological interaction (gPPI) analyses to assess changes in condition-based functional connectivity on FT. Median time between fMRI visits was 10 weeks, and median CBD dose at follow-up was 25 mg/kg/d. From PRE to ON, participants experienced improvements in seizure frequency (SF) (p = 0.0009), seizure severity (Chalfont Seizure Severity Scale (CSSS); p < 0.0001), and mood (Total Mood Disturbance (TMD) score from Profile of Mood States (POMS); p = 0.0026). Repeated measures analysis of variance showed nonsignificant improvements in executive function from 34.6 (23.5)% to 41.9 (22.4)% CON accuracy and from 34.2 (25.7)% to 37.6 (24.4)% INC accuracy (p = 0.199). Change in CON accuracy was associated with change in INC accuracy (rS = 0.81, p = 0.0005). Participants exhibited CBD-induced increases in fMRI activation in the right superior frontal gyrus (SFG) and right insula/middle frontal gyrus (MFG) and decrease in activation for both regions at ON relative to PRE (corrected p = 0.05). The subset of patients who improved in FT accuracy with CBD showed a negative association between change in right insula/MFG activation and change in accuracy for the INC condition (rS = -0.893, p = 0.0068). The gPPI analysis revealed a CBD-induced decrease in condition-based functional connectivity differences for the right SFG seed region (corrected p = 0.05). Whole-brain regression analysis documented a negative association of change in right insula/MFG condition-based connectivity with change in INC accuracy (corrected p = 0.005). Our results suggest that CBD modulates attention control processing in patients with TRE by reducing right SFG and right insula/MFG activation related to stimulus conflict resolution and by dampening differences in condition-based functional connectivity of the right SFG. Our study is the first to provide insight into how CBD affects the neural substrates involved in attention processing and how modulation of the activity and functional connectivity related to attentional control processes in the right insula/MFG may be working to improve cognitive performance in TRE.

Quantification of changes in brain morphology following posterior fossa decompression surgery in women treated for Chiari malformation type 1.

PURPOSE: While 84% of patients surgically treated for Chiari malformation type 1 (CM1) demonstrate improved quality of life after posterior fossa decompression surgery, there are many risks associated with this surgery. Surgical planning to identify candidates likely to improve postoperatively may benefit from an improved understanding of morphological changes after decompression surgery. To evaluate these changes, we quantified 59 morphological parameters on 42 CM1 adult female patients before and after CM1 decompression surgery. METHODS: Fifty-nine morphological parameters in the posterior cranial fossa, cranio-cervical, and intracranial regions in the midsagittal plane were evaluated using 42 T1-weighted magnetic resonance images of female CM1 patients before and after surgery, and 42 healthy female controls. Morphological differences before and after surgery were compared through the development of a technique to establish the opisthion location, a key reference point not present after surgery. RESULTS: In addition to the expected reduction of the cranio-caudal dimension of the cerebellum, objective analyses showed a significant increase in the area of the cerebrospinal fluid spaces, posterior (6×) and inferior (2.6×) to the cerebellum (+ 112 ± 102 and + 140 ± 127 mm2, respectively). This increased area was primarily impacted by an average reduction in the occipital bone length of 24.5 ± 7.3 mm following surgery. Based on multiple angles, results demonstrated a 2°-4° anterior rotation of the cerebellum after surgery. CONCLUSION: Our results show that decompression surgery results in significant changes in the cerebellum and cerebrospinal fluid spaces. Further investigation should determine how these morphological changes impact clinical outcomes.

Are There Age Differences in Consolidated Episodic Memory?

Background/Study Context: While most aging research on memory uses a retention interval of one hour or less, episodic consolidation takes longer (e.g., 6-24 hours for synaptic consolidation). In three experiments, we examined age differences in recall followed by recognition in which the retention interval was varied in younger and older adults. METHODS: In Experiment 1 (n = 24 for both age groups), zero-, 1- and 24-hour retention intervals were used for recall for all participants, and a 24-hour retention interval was used for recognition. In Experiment 2 (n = 24 for both age groups), just a 24-hour retention interval was used. In Experiment 3 (n = 20 for both age groups), a within-subjects design was used in which participants recalled one word list after one hour and again after 24 hours, and recalled another word list just after 24 hours (with recognition for both conditions after the 24-hour recall). RESULTS: In Experiment 1, older adults recalled fewer words at both the 1- and 24-hour retention intervals, but the magnitude of the age difference did not differ. In Experiment 2 (just 24-hour retention interval), there were no age differences in recall. In Experiment 3, in the two-recall condition, older adults showed lower recall at both 1-hour and 24-hour retention intervals (but the magnitude of the age difference remained constant across retention interval). In the single-recall just 24-hour retention condition, there were no age differences. There were no age differences in recognition in any of the three experiments. CONCLUSION: These results suggest that recall declines for a 24-hour retention interval relative to a zero or one-hour retention interval (Experiments 1 and 3) for both age groups. However, when the first recall attempt occurs after a 24-hour retention interval, there are no age differences. These replicated results suggest that older adults do not benefit as much as younger adults from pre-consolidated rehearsal, but that rehearsal-based age differences do not increase in magnitude from the last rehearsal to memory consolidation. Furthermore, (along with), the present results indicate that there are no age differences in recall when the first recall attempt occurs after a long retention interval - when memory consolidation is likely to have occurred before the first retrieval attempt.

An Electrophysiological Study of Cognitive and Emotion Processing in Type I Chiari Malformation.

Type I Chiari malformation (CMI) is a neurological condition in which the cerebellar tonsils descend into the cervical spinal subarachnoid space resulting in cervico-medullary compression. Early case-control investigations have indicated cognitive deficits in the areas of attention, memory, processing speed, and visuospatial function. The present study further examined cognitive and emotional processing deficits associated with CMI using a dual-task paradigm. Nineteen CMI patients were recruited during pre-surgical consultation and 19 matched control participants identified emotional expressions in separate single and asynchronous dual-task designs. To extend earlier behavioral studies of cognitive effects in CMI, we recorded event-related potentials (ERPs) in the dual-task design. Though response times were slower for CMI patients across the two tasks, behavioral and ERP analyses indicated that patients did not differ from matched controls in the ability to allocate attentional resources between the two tasks. P1 ERP component analyses provided no indication of an emotional arousal deficit in our CMI sample while P3 ERP component analyses suggested a CMI-related deficit in emotional regulation. P3 analysis also yielded evidence for a frontalization of neurophysiological activity in CMI patients. Pain and related depression and anxiety factors accounted for CMI deficits in single-task, but not dual-task, response times. Results are consistent with a dysfunctional fronto-parietal attentional network resulting from either the indirect effects of chronic pain or the direct effects of CMI pathophysiology stemming from cervico-medullary compression.

Emotional arousal deficit or emotional regulation bias? An electrophysiological study of age-related differences in emotion perception.

Background/Study context: Adult age differences in emotion processing have been attributed to age-related decline in earlier emotional perception and age-related bias in later emotional regulation. Yet, the relationship between the processes of early emotion perception and bias in emotional regulation and their influence on behavioral outcomes remains unclear. Event-related potentials (ERPs) have the temporal precision to allow for the online measure of neurophysiological activity and provide potential insight into the complex dynamics of emotion processing and aging. METHODS: ERPs were used as the primary measure to examine the hypotheses that younger adults will differ in emotional arousal and emotional bias as represented by the early P1 waveform and later P3 waveform, respectively. Thirty-two younger and older adults (16 each) performed a facial emotion discrimination task in which they identified standardized angry, happy, or neutral expressions of faces from the NimStim database. RESULTS: Younger adults showed a greater P1 ERP for angry faces relative to happy faces at parietal channels, while older adults did not exhibit any emotional modulation of the P1. In contrast, both younger and older adults showed a greater late P3 ERP for angry faces compared to happy faces. CONCLUSION: The authors' results provide evidence for an age-related deficit in early emotion perception and autonomic arousal. Younger adults, but not older adults, exhibited a pattern of neurophysiological activity believed to reflect preconscious and reflexive identification of threat. Despite these age group differences in early emotion processing, younger and older adults did not exhibit differences in neurophysiological processes believed to reflect emotion regulation.

A morphometric assessment of type I Chiari malformation above the McRae line: A retrospective case-control study in 302 adult female subjects.

PURPOSE: Type I Chiari malformation (CMI) is a radiologically-defined structural dysmorphism of the hindbrain and posterior cranial fossa (PCF). Traditional radiographic identification of CMI relies on the measurement of the cerebellar tonsils in relation to the foramen magnum with or without associated abnormalities of the neuraxis. The primary goal of this retrospective study was to comprehensively assess morphometric parameters above the McRea line in a group of female CMI patients and normal controls. MATERIAL AND METHODS: Twenty-nine morphological measurements were taken on 302 mid-sagittal MR images of adult female CMI patients (n=162) and healthy controls (n=140). All MR images were voluntarily provided by CMI subjects through an online database and control participant images were obtained through the Human Connectome Project and a local hospital system. RESULTS: Analyses were performed on the full dataset of adult female MR images and a restricted dataset of 229 participants that were equated for age, race, and body mass index. Eighteen group differences were identified in the PCF area that we grouped into three clusters; PCF structures heights, clivus angulation, and odontoid process irregularity. Fourteen group differences persisted after equating our CMI and control groups on demographic characteristics. CONCLUSION: PCF structures reliably differ in adult female CMI patients relative to healthy controls. These differences reflect structural abnormalities in the osseous and soft tissue structures of the clivus, odontoid process, and cerebellum. Clinical and pathophysiological implications are discussed.