1
|
Torres L, Geier TJ, Tomas CW, Bird CM, Timmer-Murillo S, Larson CL, deRoon-Cassini TA. Racial discrimination increases the risk for nonremitting posttraumatic stress disorder symptoms in traumatically injured Black individuals living in the United States. J Trauma Stress 2024. [PMID: 38650107 DOI: 10.1002/jts.23051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/12/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Traumatic, life-threatening events are experienced commonly among the general U.S. population, yet Black individuals in the United States (i.e., Black Americans) exhibit higher prevalence rates of posttraumatic stress disorder (PTSD) and more severe symptoms than other populations. Although empirical research has noted a range of symptom patterns that follow traumatic injury, minimal work has examined the role of racial discrimination in relation to PTSD symptom trajectories. The current study assessed racial discrimination and PTSD symptom trajectories at 6 months postinjury across two separate samples of traumatically injured Black Americans (i.e. emergency department (ED)-discharged and hospitalized). Identified PTSD symptom trajectories largely reflect those previously reported (i.e., ED: nonremitting, moderate, remitting, and resilient; hospitalized: nonremitting, delayed, and resilient), although the resilient trajectory was less represented than expected given past research (ED: 55.8%, n = 62; hospitalized: 46.9%, n = 38). Finally, higher racial discrimination was associated with nonremitting, ED: relative risk ratio (RR) = 1.32, hospitalized: RR = 1.23; moderate, ED: RR = 1.18; and delayed, hospitalized: RR = 1.26, PTSD symptom trajectories. Overall, the current findings not only emphasize the inimical effects of racial discrimination but also demonstrate the unique ways in which race-related negative events can impact PTSD symptom levels and recovery across time.
Collapse
Affiliation(s)
- Lucas Torres
- Department of Psychology, Marquette University, Milwaukee, Wisconsin, USA
| | - Timothy J Geier
- Department of Surgery, Division of Trauma & Acute Care Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Carissa W Tomas
- Institute for Health and Equity, Division of Epidemiology and Social Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Claire M Bird
- Baylor Scott and White Research Institute, Trauma Research Consortium, Baylor University Medical Center, Dallas, Texas, USA
| | - Sydney Timmer-Murillo
- Department of Surgery, Division of Trauma & Acute Care Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christine L Larson
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Terri A deRoon-Cassini
- Department of Surgery, Division of Trauma & Acute Care Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| |
Collapse
|
2
|
Bird CM, Kate Webb E, Cole SW, Tomas CW, Knight JM, Timmer-Murillo SC, Larson CL, deRoon-Cassini TA, Torres L. Experiences of racial discrimination and adverse gene expression among black individuals in a level 1 trauma center sample. Brain Behav Immun 2024; 116:229-236. [PMID: 38070623 PMCID: PMC10872243 DOI: 10.1016/j.bbi.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/19/2023] Open
Abstract
Up to 40 % of individuals who sustain traumatic injuries are at risk for posttraumatic stress disorder (PTSD) and the conditional risk for developing PTSD is even higher for Black individuals. Exposure to racial discrimination, including at both interpersonal and structural levels, helps explain this health inequity. Yet, the relationship between racial discrimination and biological processes in the context of traumatic injury has yet to be fully explored. The current study examined whether racial discrimination is associated with a cumulative measure of biological stress, the gene expression profile conserved transcriptional response to adversity (CTRA), in Black trauma survivors. Two-weeks (T1) and six-months (T2) post-injury, Black participants (N = 94) provided a blood specimen and completed assessments of lifetime racial discrimination and PTSD symptoms. Mixed effect linear models evaluated the relationship between change in CTRA gene expression and racial discrimination while adjusting for age, gender, body mass index (BMI), smoking history, heavy alcohol use history, and trauma-related variables (mechanism of injury, lifetime trauma). Results revealed that for individuals exposed to higher levels of lifetime racial discrimination, CTRA significantly increased between T1 and T2. Conversely, CTRA did not increase significantly over time in individuals exposed to lower levels of lifetime racial discrimination. Thus, racial discrimination appeared to lead to a more sensitized biological profile which was further amplified by the effects of a recent traumatic injury. These findings replicate and extend previous research elucidating the processes by which racial discrimination targets biological systems.
Collapse
Affiliation(s)
| | - E Kate Webb
- McLean Hospital, Division of Depression and Anxiety Disorders, Belmont, MA USA; Harvard Medical School, Department of Psychiatry, Boston, MA USA
| | - Steven W Cole
- Cousins Center for Psychoneuroimmunology, Jane & Terry Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095, USA
| | - Carissa W Tomas
- Division of Epidemiology and Social Sciences, Institute for Health and Equity, Medical College of Wisconsin, WI, USA
| | - Jennifer M Knight
- Department of Trauma and Surgery, Medical College of Wisconsin, WI, USA
| | | | - Christine L Larson
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | | | - Lucas Torres
- Department of Psychology, Marquette University, Milwaukee, WI, USA
| |
Collapse
|
3
|
Boehm LM, Bird CM, Warren AM, Danesh V, Hosey MM, McPeake J, Potter KM, Su H, Eaton TL, Powers MB. Understanding and Managing Anxiety Sensitivity During Critical Illness and Long-Term Recovery. Am J Crit Care 2023; 32:449-457. [PMID: 37907373 DOI: 10.4037/ajcc2023975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Anxiety sensitivity is a fear of symptoms associated with anxiety (eg, rapid respiration and heart rate, perspiration), also known as "fear of fear." This fear is a misinterpretation of nonthreatening symptoms as threatening across 3 domains: physical ("When my heart rate increases, I'm afraid I may have a heart attack"), social ("If people see me perspire, I fear they will negatively evaluate me"), and cognitive ("When I feel these symptoms, I fear it means I'm going crazy or will lose control and do something dangerous like disconnect my IV"). These thoughts stimulate the sympathetic nervous system, resulting in stronger sensations and further catastrophic misinterpretations, which may spiral into a panic attack. Strategies to address anxiety sensitivity include pharmacologic and nonpharmacologic interventions. In intensive care unit settings, anxiety sensitivity may be related to common monitoring and interventional procedures (eg, oxygen therapy, repositioning, use of urine collection systems). Anxiety sensitivity can be a barrier to weaning from mechanical ventilation when patients are uncomfortable following instructions to perform awakening or breathing trials. Fortunately, anxiety sensitivity is a malleable trait with evidence-based intervention options. However, few health care providers are aware of this psychological construct and available treatment. This article describes the nature of anxiety sensitivity, its potential impact on intensive care, how to assess and interpret scores from validated instruments such as the Anxiety Sensitivity Index, and treatment approaches across the critical care trajectory, including long-term recovery. Implications for critical care practice and future directions are also addressed.
Collapse
Affiliation(s)
- Leanne M Boehm
- Leanne M. Boehm is an assistant professor, Vanderbilt University School of Nursing, Nashville, Tennessee; and an investigator, Critical Illness, Brain Dysfunction, and Survivorship (CIBS) Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Claire M Bird
- Claire M. Bird is a postdoctoral fellow, Baylor University Medical Center, Dallas, Texas
| | - Ann Marie Warren
- Ann Marie Warren is a research center director, Trauma Research Center, Baylor Scott & White Research Institute, Dallas, Texas; and an adjunct professor, Texas A&M University College of Medicine, Bryan
| | - Valerie Danesh
- Valerie Danesh is a research investigator, Center for Applied Health Research, Baylor Scott & White Research Institute; and an assistant professor, Baylor College of Medicine, Temple, Texas
| | - Megan M Hosey
- Megan M. Hosey is an assistant professor, Division of Pulmonary and Critical Care Medicine, and the Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joanne McPeake
- Joanne McPeake is a research fellow, The Healthcare Improvement Studies Institute, University of Cambridge, Cambridge, United Kingdom
| | - Kelly M Potter
- Kelly M. Potter is a research assistant professor, Clinical Research, Investigation, and Systems Modeling of Acute Illness (CRISMA) Center in the Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Han Su
- Han Su is an assistant professor, Vanderbilt University School of Nursing; and an investigator, CIBS Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Tammy L Eaton
- Tammy L. Eaton is an associate investigator, VA Health Services Research & Development, Center for Clinical Management Research, VA Ann Arbor Health System, Ann Arbor, Michigan
| | - Mark B Powers
- Mark B. Powers is a research center director, Trauma Research Center, Baylor Scott & White Research Institute, Dallas, Texas; and an adjunct professor, Texas A&M University College of Medicine, Bryan
| |
Collapse
|
4
|
Harb F, Bird CM, Webb EK, Torres L, deRoon-Cassini TA, Larson CL. Experiencing racial discrimination increases vulnerability to PTSD after trauma via peritraumatic dissociation. Eur J Psychotraumatol 2023; 14:2211486. [PMID: 37229524 DOI: 10.1080/20008066.2023.2211486] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/12/2023] [Accepted: 04/15/2023] [Indexed: 05/27/2023] Open
Abstract
Background: Racial discrimination is a traumatic stressor that increases the risk for posttraumatic stress disorder (PTSD), but mechanisms to explain this relationship remain unclear. Peritraumatic dissociation, the complex process of disorientation, depersonalization, and derealization during a trauma, has been a consistent predictor of PTSD. Experiences of frequent racial discrimination may increase the propensity for peritraumatic dissociation in the context of new traumatic experiences and contribute to PTSD symptoms. However, the role of peritraumatic dissociation in the relationship between experiences of discrimination and PTSD has not been specifically explored.Objective: The current study investigated the role of peritraumatic dissociation in the impact of racial discrimination on PTSD symptoms after a traumatic injury, and the moderating role of gender.Method: One hundred and thirteen Black/African American individuals were recruited from the Emergency Department at a Level I Trauma Center. Two weeks after the trauma, participants self-reported their experiences with racial discrimination and peritraumatic dissociation. At the six-month follow-up appointment, individuals underwent a clinical assessment of their PTSD symptoms.Results: Results of longitudinal mediation analyses showed that peritraumatic dissociation significantly mediated the effect of racial discrimination on PTSD symptoms, after controlling for age and lifetime trauma exposure. A secondary analysis was conducted to examine the moderating role of gender. Gender was not a significant moderator in the model.Conclusions: Findings show that racial discrimination functions as a stressor that impacts how individuals respond to other traumatic events. The novel results suggest a mechanism that explains the relationship between racial discrimination and PTSD symptoms. These findings highlight the need for community spaces where Black Americans can process racial trauma and reduce the propensity to detach from daily, painful realities. Results also show that clinical intervention post-trauma must consider Black Americans' experiences with racial discrimination.
Collapse
Affiliation(s)
- Farah Harb
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Claire M Bird
- Trauma Research Consortium, Baylor Scott and White Research Institute, Baylor Scott & White Health, Dallas, TX, USA
| | - E Kate Webb
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Lucas Torres
- Department of Psychology, Marquette University, Milwaukee, WI, USA
| | - Terri A deRoon-Cassini
- Department of Surgery, Division of Trauma & Acute Care Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
- Comprehensive Injury Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christine L Larson
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| |
Collapse
|
5
|
Webb EK, Bird CM, deRoon-Cassini TA, Weis CN, Huggins AA, Fitzgerald JM, Miskovich T, Bennett K, Krukowski J, Torres L, Larson CL. Racial Discrimination and Resting-State Functional Connectivity of Salience Network Nodes in Trauma-Exposed Black Adults in the United States. JAMA Netw Open 2022; 5:e2144759. [PMID: 35072718 PMCID: PMC8787596 DOI: 10.1001/jamanetworkopen.2021.44759] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/29/2021] [Indexed: 12/21/2022] Open
Abstract
Importance For Black US residents, experiences of racial discrimination are still pervasive and frequent. Recent empirical work has amplified the lived experiences and narratives of Black people and further documented the detrimental effects of racial discrimination on both mental and physical health; however, there is still a need for further research to uncover the mechanisms connecting experiences of racial discrimination with adverse health outcomes. Objective To examine neurobiological mechanisms that may offer novel insight into the association of racial discrimination with adverse health outcomes. Design, Setting, and Participants This cross-sectional study included 102 Black adults who had recently experienced a traumatic injury. In the acute aftermath of the trauma, participants underwent a resting-state functional magnetic resonance imaging scan. Individuals were recruited from the emergency department at a Midwestern level 1 trauma center in the United States between March 2016 and July 2020. Data were analyzed from February to May 2021. Exposures Self-reported lifetime exposure to racial discrimination, lifetime trauma exposure, annual household income, and current posttraumatic stress disorder (PTSD) symptoms were evaluated. Main Outcomes and Measures Seed-to-voxel analyses were conducted to examine the association of racial discrimination with connectivity of salience network nodes (ie, amygdala and anterior insula). Results A total of 102 individuals were included, with a mean (SD) age of 33 (10) years and 58 (57%) women. After adjusting for acute PTSD symptoms, annual household income, and lifetime trauma exposure, greater connectivity between the amygdala and thalamus was associated with greater exposure to discrimination (t(97) = 6.05; false discovery rate (FDR)-corrected P = .03). Similarly, racial discrimination was associated with greater connectivity between the insula and precuneus (t(97) = 4.32; FDR-corrected P = .02). Conclusions and Relevance These results add to the mounting literature that racial discrimination is associated with neural correlates of vigilance and hyperarousal. The study findings extend this theory by showing that this association is apparent even when accounting for socioeconomic position, lifetime trauma, and symptoms of psychological distress related to an acute trauma.
Collapse
Affiliation(s)
- E. Kate Webb
- Department of Psychology, University of Wisconsin–Milwaukee
| | - Claire M. Bird
- Department of Psychology, Marquette University, Milwaukee, Wisconsin
| | - Terri A. deRoon-Cassini
- Division of Trauma & Acute Care Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee
| | - Carissa N. Weis
- Institute for Health and Equity, Department of Epidemiology, Medical College of Wisconsin, Milwaukee
| | - Ashley A. Huggins
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina
| | | | | | | | - Jessica Krukowski
- Department of Psychology, Marquette University, Milwaukee, Wisconsin
| | - Lucas Torres
- Department of Psychology, Marquette University, Milwaukee, Wisconsin
| | | |
Collapse
|
6
|
Webb EK, Weis CN, Huggins AA, Fitzgerald JM, Bennett K, Bird CM, Parisi EA, Kallenbach M, Miskovich T, Krukowski J, deRoon-Cassini TA, Larson CL. Neural impact of neighborhood socioeconomic disadvantage in traumatically injured adults. Neurobiol Stress 2021; 15:100385. [PMID: 34471656 PMCID: PMC8390770 DOI: 10.1016/j.ynstr.2021.100385] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 11/30/2022] Open
Abstract
Nearly 14 percent of Americans live in a socioeconomically disadvantaged neighborhood. Lower individual socioeconomic position (iSEP) has been linked to increased exposure to trauma and stress, as well as to alterations in brain structure and function; however, the neural effects of neighborhood SEP (nSEP) factors, such as neighborhood disadvantage, are unclear. Using a multi-modal approach with participants who recently experienced a traumatic injury (N = 185), we investigated the impact of neighborhood disadvantage, acute post-traumatic stress symptoms, and iSEP on brain structure and functional connectivity at rest. After controlling for iSEP, demographic variables, and acute PTSD symptoms, nSEP was associated with decreased volume and alterations of resting-state functional connectivity in structures implicated in affective processing, including the insula, ventromedial prefrontal cortex, amygdala, and hippocampus. Even in individuals who have recently experienced a traumatic injury, and after accounting for iSEP, the impact of living in a disadvantaged neighborhood is apparent, particularly in brain regions critical for experiencing and regulating emotion. These results should inform future research investigating how various levels of socioeconomic circumstances may impact recovery after a traumatic injury as well as policies and community-developed interventions aimed at reducing the impact of socioeconomic stressors.
Collapse
Affiliation(s)
- E. Kate Webb
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| | - Carissa N. Weis
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| | - Ashley A. Huggins
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| | | | | | - Claire M. Bird
- Marquette University, Department of Psychology, Milwaukee, WI, USA
| | - Elizabeth A. Parisi
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| | - Maddy Kallenbach
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| | - Tara Miskovich
- VA Northern California Healthcare System, Martinez, CA, USA
| | | | - Terri A. deRoon-Cassini
- Medical College of Wisconsin, Department of Surgery, Division of Trauma & Acute Care Surgery, Milwaukee, WI, USA
| | - Christine L. Larson
- University of Wisconsin-Milwaukee, Department of Psychology, Milwaukee, WI, USA
| |
Collapse
|
7
|
Torres L, Pachicano JB, Bird CM, Edwards LM. Ethnic discrimination, social cohesion, and mental health among Latinx adults. Am J Orthopsychiatry 2021; 92:51-57. [PMID: 34726464 DOI: 10.1037/ort0000586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The negative effects of ethnic discrimination on depression symptoms have led researchers to identify potential risk and protective variables of this relationship. While some studies have focused on individual level factors, little research has explored the role of community-level variables, or the combination of both. The present study of Latinx adults (N = 304) tested a moderated mediation model to examine if alcohol use was a mediator of ethnic discrimination and depression under certain levels of social cohesion. Results found that alcohol use was a mediator between ethnic discrimination and depression symptoms and social cohesion moderated this relationship, such that alcohol use was not significant at higher levels of social cohesion. Implications and future directions are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Collapse
Affiliation(s)
| | | | | | - Lisa M Edwards
- Department of Counselor Education and Counseling Psychology
| |
Collapse
|
8
|
Bird CM, Webb EK, Schramm AT, Torres L, Larson C, deRoon-Cassini TA. Racial Discrimination is Associated with Acute Posttraumatic Stress Symptoms and Predicts Future Posttraumatic Stress Disorder Symptom Severity in Trauma-Exposed Black Adults in the United States. J Trauma Stress 2021; 34:995-1004. [PMID: 33715212 PMCID: PMC9123835 DOI: 10.1002/jts.22670] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/16/2021] [Accepted: 02/19/2021] [Indexed: 12/20/2022]
Abstract
In the United States, Black residents exposed to a traumatic event are at an increased risk of developing posttraumatic stress disorder (PTSD) and experiencing more severe symptoms compared to their non-Hispanic White counterparts. Although previous work has suggested a link between racial discrimination and PTSD symptoms, no studies have assessed this association in a sample of traumatic injury survivors. The current study investigated whether (a) past racial discrimination was associated with acute posttraumatic stress symptoms (PTSS) and (b) discrimination prospectively contributed to the prediction of future PTSD symptoms. African American and/or Black patients (N = 113) were recruited from an emergency department in southeastern Wisconsin. Patients in the acute postinjury phase (i.e., 2 weeks posttrauma) completed self-report measures, with PTSD symptoms assessed using the Clinician-Administered PTSD Scale at 6-month follow-up. Bivariate associations indicated past racial discrimination was significantly related to acute PTSS. A multiple regression analysis revealed that pretrauma exposure to racial discrimination significantly predicted PTSD symptoms at follow-up, even after controlling for age, gender, previous psychiatric diagnosis, social support, and lifetime trauma history. Our results suggest that experiences of racial discrimination add significant additional risk for PTSD symptom development following traumatic injury, R2 = .16, F(6, 106) = 3.25, p = .006. Broadly, these findings add to the body of empirical evidence and personal testimonies of Black individuals in White-centric societies asserting that racial discrimination affects mental health and overall well-being and further highlight the recent call for racism to be classified as a public health crisis.
Collapse
Affiliation(s)
- Claire M. Bird
- Department of Psychology, Marquette University, Milwaukee, Wisconsin, USA
| | - E. Kate Webb
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Andrew T. Schramm
- Division of Trauma and Acute Care Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Lucas Torres
- Department of Psychology, Marquette University, Milwaukee, Wisconsin, USA
| | - Christine Larson
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Terri A. deRoon-Cassini
- Division of Trauma and Acute Care Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| |
Collapse
|
9
|
Cipolotti L, Husain M, Crinion J, Bird CM, Khan SS, Losseff N, Howard RS, Leff AP. The role of the thalamus in amnesia: a tractography, high-resolution MRI and neuropsychological study. Neuropsychologia 2008; 46:2745-58. [PMID: 18597798 DOI: 10.1016/j.neuropsychologia.2008.05.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/06/2008] [Accepted: 05/11/2008] [Indexed: 11/18/2022]
Abstract
Although it is well established that thalamic lesions may lead to profound amnesia, the precise contribution of thalamic sub-regions to memory remains unclear. In an influential article Aggleton and Brown proposed that recognition memory depends on two processes supported by distinct thalamic and cortical structures. Familiarity is mediated by the mediodorsal (MD) thalamic nucleus and the entorhinal/perirhinal cortex. Recollection is mediated by the anterior thalamic nucleus (AN), the mamillothalamic tract (MTT) and the hippocampus. The authors also suggested that the lateral dorsal nucleus (LD) may contribute to the thalamic/hippocampus system, thereby implying that the LD may play a role in recollection. Given the finding that material specific amnesia can occur following thalamic lesions, we tested an extension of the Aggleton and Brown model. We predicted that patients with bilateral lesions with a bias to the left or right MD or AN/MTT/LD may exhibit impaired familiarity or recollection on verbal or non-verbal memoranda. We report two patients with highly focal thalamic lesions and profound memory impairments affecting verbal and non-verbal memoranda. For the first time, diffusion-weighted imaging was employed to perform tractography of the MTT along with high-resolution anatomical MRI and detailed assessments of verbal and non-verbal memory. Our data support only some aspects of the Aggleton and Brown model. Both patients had left MD nucleus and AN/MTT lesions and performed poorly on familiarity and recall for verbal memoranda, just as predicted by the model. However, both patients' performance for non-verbal memoranda (human faces and topography) is more difficult to reconcile with the model. Patient 1 had damage to the right AN/MTT/LD with sparing of the MD: familiarity should therefore have been preserved but was not. Patient 2 had damage to the right MD with sparing of AN/MTT: recollection should have been preserved but was not. This finding raises the possibility that fractionation of familiarity and recollection to separate thalamic nuclei may not fully capture the role of thalamic sub-regions in memory function.
Collapse
Affiliation(s)
- L Cipolotti
- Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
OBJECTIVES To investigate the characteristics and neuroanatomical correlates of visual neglect after right-sided posterior cerebral artery (PCA) infarction. METHODS 15 patients with acute PCA strokes were screened for the presence of neglect on a comprehensive battery of cognitive tests. Extra tests of visual perception were also carried out on six patients. To establish which areas were critically associated with neglect, the lesions of patients with and without neglect were compared. RESULTS Neglect of varying severity was documented in 8 patients. In addition, higher-order visual perception was impaired in 5 of the 6 patients. Neglect was critically associated with damage to an area of white matter in the occipital lobe corresponding to a white matter tract connecting the parahippocampal gyrus with the angular gyrus of the parietal lobe. Lesions of the thalamus or splenium of the corpus callosum did not appear necessary or sufficient to cause neglect, but may mediate its severity in these patients. CONCLUSIONS PCA stroke can result in visual neglect. Interruption of the white matter fibres connecting the parahippocampal gyrus to the angular gyrus may be important in determining whether a patient will manifest neglect.
Collapse
Affiliation(s)
- C M Bird
- Institute of Cognitive Neuroscience, University College London, 17, Queen Square, London WC1N 3AR, UK.
| | | | | | | | | | | |
Collapse
|
11
|
Abstract
This article describes an investigation into the residual writing skills of a severely dysgraphic patient (DA). We found that they were powerfully influenced by a number of lexical variables (lexicality, frequency, imageability, length and geminates). His error pattern was characterized by semantic, lexical, substitution, deletion errors and fragment responses that preserved the first letter. Thus, DA's written spelling was characterized by both deep dysgraphic and graphemic output buffer effects. It is proposed that this pattern of performance represents a new"putative functional syndrome."
Collapse
Affiliation(s)
- L Cipolotti
- Department of Neuropsychology, National Hospital for Neurology & Neurosurgery, London, UK.
| | | | | | | |
Collapse
|
12
|
Abstract
Detection performance was measured with sinusoidal and pulse-train gratings. Although the 2.09-cycles-per-degree pulse-train, or line, grating contained at least eight harmonics all at equal contrast, it was no more detectable than its most detectable component. The addition of broadband pink noise designed to equalize the detectability of the components of the pulse train made the pulse train approximately a factor of 4 more detectable than any of its components. However, in contrast-discrimination experiments, with a pedestal or masking grating of the same form and phase as the signal and with 15% contrast, the noise did not affect the discrimination performance of the pulse train relative to that obtained with its sinusoidal components. We discuss the implications of these observations for models of early vision, in particular the implications for possible sources of internal noise.
Collapse
Affiliation(s)
- G B Henning
- The Department of Experimental Psychology, University of Oxford, UK
| | | | | |
Collapse
|
13
|
Bird CM, Henning GB, Wichmann FA. Contrast discrimination with sinusoidal gratings of different spatial frequency. J Opt Soc Am A Opt Image Sci Vis 2002; 19:1267-1273. [PMID: 12095194 DOI: 10.1364/josaa.19.001267] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The detectability of contrast increments was measured as a function of the contrast of a masking or "pedestal" grating at a number of different spatial frequencies ranging from 2 to 16 cycles per degree of visual angle. The pedestal grating always had the same orientation, spatial frequency, and phase as the signal. The shape of the contrast-increment threshold versus pedestal contrast (TvC) functions depends on the performance level used to define the "threshold," but when both axes are normalized by the contrast corresponding to 75% correct detection at each frequency, the TvC functions at a given performance level are identical. Confidence intervals on the slope of the rising part of the TvC functions are so wide that it is not possible with our data to reject Weber's law.
Collapse
Affiliation(s)
- C M Bird
- Department of Neuropsychology, The National Hospital, London, UK
| | | | | |
Collapse
|
14
|
Abstract
Patients using domiciliary nasal ventilation, or long-term oxygen, require regular assessment which could be carried out in the home. Blood gas analysis may be regarded as an essential part of the assessment. The present study investigated the effect of a 1-h time delay on the measurement of capillary blood gases. Four samples of arterialized earlobe blood were collected from 15 outpatients. One sample was analysed immediately, the other three were stored on crushed ice and analysed at intervals of 30, 45, and 60 min post-collection. In order to examine any range effect, a wide range of PaO2 values were examined. The delay, at all levels, resulted in minor changes in the measurement of PaO2, which would be unlikely to alter clinical management. The technique might be used for the reliable assessment of patients in the home.
Collapse
Affiliation(s)
- C M Bird
- Department of Respiratory Physiology, Glenfield Hospital, Leicester, U.K
| | | | | | | |
Collapse
|