An examination of pain, disability, and the psychological correlates of Chiari Malformation pre- and post-surgical correction

Cognition in Chiari Malformation Type I: an Update of a Systematic Review

Chiari malformation has been classified as a group of posterior cranial fossa disorders characterized by hindbrain herniation. Chiari malformation type I (CM-I) is the most common subtype, ranging from asymptomatic patients to those with severe disorders. Research about clinical manifestations or medical treatments is still growing, but cognitive functioning has been less explored. The aim of this systematic review is to update the literature search about cognitive deficits in CM-I patients. A literature search was performed through the following electronic databases: MEDLINE, PsychINFO, Pubmed, Cochrane Library, Scopus, and Web of Science. The date last searched was February 1, 2023. The inclusion criteria were as follows: (a) include pediatric or adult participants with a CM-I diagnosis, (b) include cognitive or neuropsychological assessment with standardized tests, (c) be published in English or Spanish, and (d) be empirical studies. Articles that did not report empirical data, textbooks and conference abstracts were excluded. After the screening, twenty-eight articles were included in this systematic review. From those, twenty-one articles were focused on adult samples and seven included pediatric patients. There is a great heterogeneity in the recruited samples, followed methodology and administered neurocognitive protocols. Cognitive functioning appears to be affected in CM-I patients, at least some aspects of attention, executive functions, visuospatial abilities, episodic memory, or processing speed. However, these results require careful interpretation due to the methodological limitations of the studies. Although it is difficult to draw a clear profile of cognitive deficits related to CM-I, the literature suggests that cognitive dysfunction may be a symptom of CM-I. This suggest that clinicians should include cognitive assessment in their diagnostic procedures used for CM-I. In summary, further research is needed to determine a well-defined cognitive profile related to CM-I, favoring a multidisciplinary approach of this disorder.

Impact of chronic pain and depressive symptoms on the quality of life of adults with Chiari Malformation type I: A comparative study

Chiari Malformation type I (CM-I) is a neurological disorder characterized by cerebellar tonsillar herniation. Chronic pain, particularly headaches, is a prevalent symptom in CM-I patients, significantly impacting their quality of life. The objective of this study was to evaluate the perceived quality of life in adults with CM-I and examine the influence of chronic pain and comorbid symptoms on their well-being. 26 CM-I patients (8 with decompressive surgery) and 26 matched healthy controls were recruited. Participants completed the following questionnaires: WHOQOL-BREF, HDI, NDI, OLBPDQ and HADS. CM-I patients exhibited significantly lower scores across all domains of quality of life when compared to healthy controls. Chronic pain, including headache, neck pain, and low back pain, was more pronounced among CM-I patients and demonstrated a significant correlation with depressive symptoms. Notably, after controlling for chronic pain, the differences in quality of life between CM-I patients and controls diminished. The results suggest that chronic pain, especially headaches, and comorbid depressive symptoms exert a substantial impact on the quality of life of CM-I patients. Surgical intervention alone may not fully address these issues, highlighting the importance of considering psychological interventions as part of the comprehensive treatment. Further research with larger samples and pre-post-surgery assessments is needed to validate these findings and explore the potential benefits of psychological therapies in enhancing the quality of life for CM-I patients.

Exploring pathogenesis, prevalence, and genetic associations in Chiari malformation type 1: a contemporary perspective

Chiari malformation type 1 (CM 1) entails a structural defect in the cerebellum, involving the herniation of cerebellar tonsils toward the foramen magnum. The symptomatic or asymptomatic nature of CM 1 is contingent upon the condition of malformation in the spinal cord. This review presents an updated perspective on the prevalence of CM 1, its pathogenesis, genetic associations, and treatment. CM 1 exhibits a higher prevalence in adult females than males. Despite the incomplete understanding of the exact cause of CM 1, recent research suggests the involvement of both genetic and environmental factors in its development. One of the reasons for the occurrence of CM 1 in individuals is the smaller posterior cranial fossa, which manifests as typical morphological features. Additionally, environmental factors can potentially interact with genetic factors, modifying the observable characteristics of the disease and affecting the symptoms, severity, and development of the condition. Notably, headaches, neck pain, dizziness, and neurological deficits may be exhibited by individuals with CM 1, highlighting the importance of early diagnosis. Magnetic resonance imaging (MRI) serves as an alternative diagnostic technique for monitoring the symptoms of CM 1. Multiple genetic factors are likely to contribute to a cascade of abnormalities in CM 1. Early studies provided evidence, including clustering within families, bone development, and co-segregation with known genetic syndromes, establishing CM 1's association with a genetic basis. Furthermore, surgery is the only available treatment option to alleviate symptoms or hinder the progression of damage to the central nervous system (CNS) in CM 1 cases.

A Rare Case of Arnold Chiari Malformation Type 1 Presenting With Features of Catatonia

The Arnold Chiari malformation is a congenital neurological condition. It occurs due to a defect in the cerebellum. Our patient is a 19-year-old postpartum female who presented to our ER with headaches, crying spells, reduced interaction, poor self-care, and neglect of her newborn for the past five days. Before the onset of her presenting symptoms, the patient had complained of a severe headache in the back of the head and dizziness. Her baseline investigations were normal. On examination, the patient was noticed to have a fixed gaze, ambiguity, mutism, and rigidity. So, she was diagnosed with catatonia, a differential diagnosis of mental and behavioral disorders associated with pregnancy, childbirth, and puerperium, and was treated with medications appropriately. As her headache showed minimal relief with adequate analgesic measures, neuroimaging was done, which showed Arnold Chiari malformation type I with hydrocephalus. A liaison was made with the neurology team, who confirmed the diagnosis and advised her on the decompression procedure. Her family refused to undergo the procedure. Once she showed minimal improvement in her symptoms, her family members requested her discharge. In our case, the Arnold Chiari malformation type I presented with features of catatonia, unlike the usual reported presentation of depression and anxiety. This case highlights the need for a thorough evaluation of any patient presenting with catatonia.

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.

Revisiting the factor structure of the Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2): Evidence for a bifactor model in individuals with Chiari malformation

The Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2; Dworkin et al., 2009) is intended to measure the multidimensional qualities of pain (i.e., continuous, intermittent, neuropathic, and affective) as well as total pain. Using structural equation modeling, we evaluated the fit of four competing measurement models of the SF-MPQ-2-an oblique 4-factor model, a 1-factor model, a higher-order model, and a bifactor model-in 552 adults diagnosed with Chiari malformation, a chronic health condition whose primary symptoms include head and neck pain. Results revealed the strongest support for the bifactor model, suggesting that SF-MPQ-2 item responses are due to both a general pain factor and a specific pain factor that is orthogonal to the general pain factor. Additional bifactor analyses of the SF-MPQ-2's model-based reliability and dimensionality revealed that most of the SF-MPQ-2's reliable variance is explained by a general pain factor, and that the instrument can be modeled unidimensionally and scored as a general pain measure. Results also indicated that the general and affective pain factors in the bifactor model uniquely predicted pain-related external criteria (e.g., depression, anxiety, and stress); however, the continuous, intermittent, and neuropathic factors did not.

Association between resistance to cerebrospinal fluid flow and cardiac-induced brain tissue motion for Chiari malformation type I

PURPOSE

Chiari malformation type I (CMI) patients have been independently shown to have both increased resistance to cerebrospinal fluid (CSF) flow in the cervical spinal canal and greater cardiac-induced neural tissue motion compared to healthy controls. The goal of this paper is to determine if a relationship exists between CSF flow resistance and brain tissue motion in CMI subjects.

METHODS

Computational fluid dynamics (CFD) techniques were employed to compute integrated longitudinal impedance (ILI) as a measure of unsteady resistance to CSF flow in the cervical spinal canal in thirty-two CMI subjects and eighteen healthy controls. Neural tissue motion during the cardiac cycle was assessed using displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) technique.

RESULTS

The results demonstrate a positive correlation between resistance to CSF flow and the maximum displacement of the cerebellum for CMI subjects (r = 0.75, p = 6.77 × 10-10) but not for healthy controls. No correlation was found between CSF flow resistance and maximum displacement in the brainstem for CMI or healthy subjects. The magnitude of resistance to CSF flow and maximum cardiac-induced brain tissue motion were not statistically different for CMI subjects with and without the presence of five CMI symptoms: imbalance, vertigo, swallowing difficulties, nausea or vomiting, and hoarseness.

CONCLUSION

This study establishes a relationship between CSF flow resistance in the cervical spinal canal and cardiac-induced brain tissue motion in the cerebellum for CMI subjects. Further research is necessary to understand the importance of resistance and brain tissue motion in the symptomatology of CMI.

Pain-depression relationship, quality of life and acceptance of illness among patients with Chiari malformation type I: A cross-sectional study

Chiari malformation type I (CM-I) is a congenital anomaly of the hindbrain. The most common symptoms include suboccipital tussive headache, dizziness and neck pain. Recently there has been growing interest in the psychological and psychiatric aspects of functioning in patients with CM-I, which have a significant effect on treatment outcomes and quality of life (QoL). The aim of the study was to assess the severity of depressive symptoms and the QoL in patients with CM-I and to identify the main factors responsible for these phenomena. A total of 178 people participated in the study and were divided into 3 groups: patients with CM-I who had undergone surgery (n = 59); patients with CM-I who had not undergone surgery (n = 63); and healthy volunteers (n = 56). Psychological evaluation included a set of questionnaires: the Beck Depression Inventory II, the World Health Organization shortened version of the WHOQOL-100 quality of life questionnaire, the Acceptance of Illness Scale and the Beliefs about Pain Control Questionnaire. Results showed that the control group participants obtained significantly better results than both groups of CM-I patients in terms of all indicators of QoL, symptoms of depression, acceptance of illness, pain level (average and present) and perceived influence of doctors regarding coping with pain. Patients with CM-I (operated and non-operated) obtained similar results in most of the questionnaires and the QoL indices correlated significantly with the majority of the analyzed variables. Moreover, CM-I patients with higher depression scores described their pain as more severe and had a stronger belief that pain levels were not influenced by them but only by doctors, or that it could be controlled randomly; they were also less willing to accept their illness. CM-I symptoms affect the mood and QoL of patients. Psychological and psychiatric care should be the golden standard in managing this clinical group.

A Systematic Review of Non-Opioid Pain Management in Chiari Malformation (Type 1) Patients: Current Evidence and Novel Therapeutic Opportunities

Chiari Malformation Type I (CM) includes a range of cranial abnormalities at the junction of the skull with the spine, with common symptoms including pain and headaches. Currently, CM pain is managed medically through anti-inflammatory drugs, muscle relaxants, and opioids, while surgical management includes posterior fossa decompression. Given the adverse effects of opioid use, and an ongoing opioid epidemic, there is a need for safe, non-opioid alternatives for clinical pain management. This systematic review was performed to provide an update on the current literature pertaining to the treatment of CM pain with non-opioid alternatives. A literature search was performed in June 2022 utilizing the PubMed and Google Scholar databases, and articles were identified that included information regarding non-opioid pain management in CM patients. A total of 90 articles were obtained from this search, including 10 relevant, drug-specific studies. Two independent reviewers selected and included all relevant articles based on the chosen search criteria to minimize bias risk. Currently available treatments for neurosurgical pain management include anticonvulsants, corticosteroids, NSAIDs, anti-inflammatory drugs, NMDA receptor antagonists, local anesthetics, nerve blocks, scalp blocks, and neuromuscular blocks. While more information is needed on the use of non-opioid pain management, the present literature provides potential evidence of its efficacy amongst the CM patient population, on account of the success that non-opioid pain management has demonstrated within other neurological pain syndromes. Further research into non-pharmacological pain management would also benefit the CM population and could be generalized to related conditions.

Effects of Two Exercise Regimes on Patients with Chiari Malformation Type 1: a Randomized Controlled Trial

This study aims to measure the effects of two different exercise programs on neck pain, proprioception, balance, coordination, posture, and quality of life in patients with Chiari malformation (CM) type 1. Sixteen patients were randomized to two different exercise programs: a tailored exercise protocol for CM (TEP-CM) and cervical spinal stabilization exercises (CSSE). Both exercise programs were implemented by a physiotherapist 3 days a week for 6 weeks. The primary outcome was Neck Disability Index. Secondary outcomes were visual analogue scale for pain, joint position sense error measurement, Berg Balance Scale, Time Up and Go Test, International Coordination Ataxia Rating Scale, PostureScreen Mobile, and Short Form-36. Assessments were done immediately before and after the intervention programs. Both groups showed significant improvement in Neck Disability Index, and some secondary outcome measures (P < 0.05). However, there were no statistical differences in post-intervention changes between the groups (P > 0.05). This is the first study to examine the effects of different exercise programs on symptoms in patients with CM type 1. Our preliminary findings indicate that exercise programs can improve pain, balance, proprioception, posture, coordination, and quality of life in CM type 1. Therefore, exercise should be considered safe, beneficial, and low-cost treatment option for CM type 1 patients without surgical indications.

Pain and Depression Account for More Than One Half of the Neck Disability Variance Among Adult Women with Chiari I

OBJECTIVE

We sought to quantify the neck-related disability in adult women with Chiari malformation type I and identify the significantly related variables.

METHODS

A total of 70 variables were selected from the self-report history questionnaires (12 variables; n = 474), standardized scales (15 variables; n = 474), and morphometric data (43 variables; n = 293-474) of adult women with Chiari malformation type I. The variables were tested independently to identify those with a significant relationship to the Neck Disability Index (NDI; P < 0.00071) and those that might be associated with the NDI (P < 0.05). A forward selection regression model was constructed to identify the variables contributing unique variance to the NDI. In addition, a mediation analysis was performed to determine whether depression mediated the relationship between pain and disability.

RESULTS

Overall, 79.5% of the patients had scored at a moderate level of disability or higher. Independent testing identified 16 significant variables, including symptom duration, tonsillar position, and measures of psychological distress. The short-form McGill pain questionnaire-2 (r = 0.69; P < 0.00001) and CES-D scale for depression (r = 0.56; P < 0.00001) exhibited the highest correlations with the NDI. The forward selection regression model produced an R2 of 0.6178. Pain and depression accounted for more than one half of the NDI variance.

CONCLUSIONS

We found that high levels of disability are common among adult women with Chiari malformation type I, independent of surgical status. Pain and depression were the primary factors related to this disability. Depression mediated the relationship between pain intensity and disability at a modest level (5%). Patients who had experienced symptoms for >2 years before diagnosis had had, on average, 77% higher NDI scores, highlighting the importance of a timely diagnosis.

The importance of precise plane selection for female adult Chiari Type I malformation midsagittal morphometrics

Introduction

Morphometric assessment of Chiari malformation type I (CMI) is typically performed on a midsagittal MRI. However, errors arising from an imprecise selection of the midsagittal plane are unknown. We define absolute parasagittal error as the absolute difference between morphometric measurements at the midsagittal and parasagittal planes. Our objective was to determine the absolute parasagittal error at various lateral distances for morphometric parameters commonly used in CMI research.

Methods

Sagittal T1-weighted MRI scans of 30 CMI adult female subjects were included. Image sets were evaluated to assess 14 CMI morphometric parameters in the midsagittal plane and four parasagittal planes located 1 and 2 mm lateral (left and right). Comparisons between measurements at the midsagittal and parasagittal planes were conducted to determine the mean individual absolute and mean group parasagittal errors for all 14 parameters.

Results

The mean individual absolute parasagittal error was > 1 unit (1 mm for lengths and 1 degree for angles) for 9/14 parameters within a lateral distance of 2 mm. No significant group parasagittal errors were seen in 14/14 parameters, including tonsillar position within a lateral distance of 2 mm.

Conclusion

Our results show that the absolute errors for imprecise midsagittal plane selection may impact the clinical assessment of an individual patient. However, the impact on group measurements, such as in a research setting, will be minimal.

A new hypothesis for the pathophysiology of symptomatic adult Chiari malformation Type I

Chiari malformation Type I (CMI) is characterized by herniation of the cerebellar tonsils through the foramen magnum. The pathophysiology of CMI is not well elucidated; however, the prevailing theory focuses on the underdevelopment of the posterior cranial fossa which results in tonsillar herniation. Symptoms are believed to be due to the herniation causing resistance to the natural flow of cerebrospinal fluid (CSF) and exerting a mass effect on nearby neural tissue. However, asymptomatic cases vastly outnumber symptomatic ones and it is not known why some people become symptomatic. Recently, it has been proposed that CMI symptoms are primarily due to instability of either the atlanto-axial (AA) or the atlanto-occipital (AO) joint and the cerebellar tonsils herniate to prevent mechanical pinching. However, only a small percentage of patients exhibit clinical instability and these theories do not account for asymptomatic herniations. We propose that the pathophysiology of adult CMI involves a combination of craniocervical abnormalities which leads to tonsillar herniation and reduced compliance of the cervical spinal canal. Specifically, abnormal AO and/or AA joint morphology leads to chronic cervical instability, often subclinical, in a large portion of CMI patients. This in turn causes overwork of the suboccipital muscles as they try to compensate for the instability. Over time, the repeated, involuntary activation of these muscles leads to mechanical overload of the myodural bridge complex, altering the mechanical properties of the dura it merges with. As a result, the dura becomes stiffer, reducing the overall compliance of the cervical region. This lower compliance, combined with CSF resistance at the same level, leads to intracranial pressure peaks during the cardiac cycle (pulse pressure) that are amplified during activities such as coughing, sneezing, and physical exertion. This increase in pulse pressure reduces the compliance of the cervical subarachnoid space which increases the CSF wave speed in the spinal canal, and further increases pulse pressure in a feedback loop. Finally, the abnormal pressure environment induces greater neural tissue motion and strain, causing microstructural damage to the cerebellum, brainstem, and cervical spinal cord, and leading to symptoms. This hypothesis explains how the combination of craniocervical bony abnormalities, anatomic CSF restriction, and reduced compliance leads to symptoms in adult CMI.

Cognitive and Psychological Functioning in Chiari Malformation Type I Before and After Surgical Decompression - A Prospective Cohort Study

BACKGROUND

Chiari Malformation Type I (CM-I) is defined as cerebellar tonsil displacement more than 5 mm below the foramen magnum. This displacement can alter cerebrospinal fluid flow at the cervicomedullary junction resulting in Valsalva-induced headaches and syringomyelia and compress the brainstem resulting in bulbar symptoms. However, little is known about cognitive and psychological changes in CM-I.

OBJECTIVE

To prospectively assess cognitive and psychological performance in CM-I and determine whether changes occur after surgical decompression.

METHODS

Blinded evaluators assessed symptomatic CM-I patients ages ≥18 with a battery of neuropsychological and psychological tests. Testing was conducted preoperatively and 6 to 18 mo postoperatively. Data were converted to Z-scores based on normative data, and t-tests were used to analyze pre-post changes.

RESULTS

A total of 26 patients were included, with 19 completing both pre- and post-op cognitive assessments. All patients had resolution of Valsalva-induced headaches and there was improvement in swallowing dysfunction (P < .0001), ataxia (P = .008), and sleep apnea (P = .021). Baseline performances in visual perception and construction (z = -1.11, P = .001) and visuospatial memory (z = -0.93, P = .002) were below average. Pre-post comparisons showed that CM-I patients had stable cognitive and psychological functioning after surgery, without significant changes from preoperative levels.

CONCLUSION

CM-I patients had below average performance in visuospatial and visuoconstructional abilities preoperatively. Prospective longitudinal data following surgery demonstrated improved neurologic status without any decline in cognition or psychological functioning. Routine pre- and postoperative formal neuropsychological assessment in CM-I patients help quantify cognitive and behavioral changes associated with surgical decompression.

Functional connectivity abnormalities in Type I Chiari: associations with cognition and pain

There is initial evidence of microstructural abnormalities in the fibre-tract pathways of the cerebellum and cerebrum of individuals diagnosed with Type I Chiari malformation. However, it is unclear whether abnormal white matter architecture and macro-level morphological deviations that have been observed in Chiari translate to differences in functional connectivity. Furthermore, common symptoms of Chiari include pain and cognitive deficits, but the relationship between these symptoms and functional connectivity has not been explored in this population. Eighteen Type I Chiari patients and 18 age-, sex- and education-matched controls underwent resting-state functional MRI to measure functional connectivity. Participants also completed a neuropsychological battery and completed self-report measures of chronic pain. Group differences in functional connectivity were identified. Subsequently, pathways of significant difference were re-analyzed after controlling for the effects of attention performance and self-reported chronic pain. Chiari patients exhibited functional hypoconnectivity between areas of the cerebellum and cerebrum. Controlling for attention eliminated all deficits with the exception of that from the posterior cerebellar pathway. Similarly, controlling for pain also eliminated deficits except for those from the posterior cerebellar pathway and vermis VII. Patterns of Chiari hyperconnectivity were also found between regions of the cerebellum and cerebrum in Chiari patients. Hyperconnectivity in all regions was eliminated after controlling for attention except between left lobule VIII and the left postcentral gyrus and between vermis IX and the precuneus. Similarly, hyperconnectivity was eliminated after controlling for pain except between the default mode network and globus pallidus, left lobule VIII and the left postcentral gyrus, and Vermis IX and the precuneus. Evidence of both hyper- and hypoconnectivity were identified in Chiari, which is posited to support the hypothesis that the effect of increased pain in Chiari draws on neural resources, requiring an upregulation in inhibitory control mechanisms and resulting in cognitive dysfunction. Areas of hypoconnectivity in Chiari patients also suggest disruption in functional pathways, and potential mechanisms are discussed.

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.

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.

Association Between Resistance to Cerebrospinal Fluid Flow Near the Foramen Magnum and Cough-Associated Headache in Adult Chiari Malformation Type I

Cough-associated headaches (CAHs) are thought to be distinctive for Chiari malformation type I (CMI) patients and have been shown to be related to the motion of cerebrospinal fluid (CSF) near the foramen magnum (FM). We used computational fluid dynamics (CFD) to compute patient-specific resistance to CSF motion in the spinal canal for CMI patients to determine its accuracy in predicting CAH. Fifty-one symptomatic CMI patients with cerebellar tonsillar position (CTP) ≥ 5 mm were included in this study. The patients were divided into two groups based on their symptoms (CAH and non-CAH) by review of the neurosurgical records. CFD was utilized to simulate CSF motion, and the integrated longitudinal impedance (ILI) was calculated for all patients. A receiver operating characteristic (ROC) curve was evaluated for its accuracy in predicting CAH. The ILI for CMI patients with CAH (776 dyn/cm5, 288-1444 dyn/cm5; median, interquartile range) was significantly larger compared to non-CAH (285 dyn/cm5, 187-450 dyn/cm5; p = 0.001). The ILI was more accurate in predicting CAH in CMI patients than the CTP when the comparison was made using the area under the ROC curve (AUC) (0.77 and 0.70, for ILI and CTP, respectively). ILI ≥ 750 dyn/cm5 had a sensitivity of 50% and a specificity of 95% in predicting CAH. ILI is a parameter that is used to assess CSF blockage in the spinal canal and can predict patients with and without CAH with greater accuracy than CTP.

Social Cognition in Chiari Malformation Type I: a Preliminary Characterization

Chiari malformation type I (CM-I) is a neurological disorder in which cerebellar tonsils are herniated through the foramen magnum into the spinal canal. A wide spectrum of cognitive deficits underlying this pathology has been reported, but the literature about social cognition is insufficient. Clinical research has pointed out the cerebellar role in Theory of Mind (ToM), indicating that there are several disorders with cerebellar pathology that reveal a poorer performance in social cognition tasks. The main purpose of this study is to compare the performance on ToM tasks between CM-I patients and healthy controls. The protocol includes Faux Pas test, Happé's Strange Stories test, Ice-Cream Van task, the FEEL test, and the Word Accentuation Test. In order to eliminate the possible influence of covariables, physical pain and anxious-depressive symptomatology have been controlled for. According to the results, CM-I patients performed worse than matched healthy controls on ToM tasks, except for facial emotion recognition. These differences remained even after controlling for the neuropsychiatric variables and physical pain. Thus, it can be suggested that patients with CM-I are impaired in their social skills related to their performance on ToM tasks. These findings can be considered to be a preliminary approach to the specific study of social cognition in relation to CM-I since it is similar to other cerebellar pathologies and to previous literature on the cerebellum's role in social cognition.

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, η²_P = .11, and lower levels of estrogen, F(1, 36) = 7.29, p = .01, η²_P = .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.

The impact of depression on surgical outcome in Chiari malformation type I: an assessment based on the Chicago Chiari Outcome Scale

OBJECTIVE

The effect of depression on outcomes in Chiari malformation type I (CM-1) is unclear. The authors sought to determine whether depression affects outcome in a surgical cohort of CM-1 patients by using a validated outcome assessment tool, the Chicago Chiari Outcome Scale (CCOS).

METHODS

The authors performed a retrospective analysis of a prospectively maintained database of 149 adult CM-1 patients undergoing suboccipital decompression with duraplasty and cranioplasty. Baseline presentation characteristics and composite as well as subcomponent CCOS scores at last follow-up were compared between depressed and nondepressed patients. Outcome comparisons included both a univariable analysis and a logistic regression model adjusting for several covariates.

RESULTS

The prevalence of depression in the study cohort was 28% (41/149). Baseline demographic and imaging characteristics were similar between the 2 patient groups. Dizziness (p = 0.019) and imbalance (p = 0.015) were significantly more common among depressed patients, but clinical symptoms and severity were otherwise comparable. On univariable analysis, depressed patients were significantly less likely to experience improvement in pain symptoms (OR 0.14, 95% CI 0.03-0.61, p = 0.003) and functionality (OR 0.17, 95% CI 0.03-0.99, p = 0.049). No significant difference was identified in complications, nonpain symptom improvement, or overall composite CCOS improvement. Similar results were obtained on multivariable analysis controlling for several covariates.

CONCLUSIONS

Depression is independently associated with poor surgical outcome in adult CM-1 patients, namely when evaluating improvement in pain symptoms and functionality. Optimizing the management of depression preoperatively and ensuring follow-up for psychiatric comorbidity in the postoperative period may possibly lead to improved outcomes.

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.