Sarah Asmussen - Academia.edu (original) (raw)
Papers by Sarah Asmussen
The Journal of head trauma rehabilitation
To explore the taxonomy of combat-related mild traumatic brain injury (mTBI) based on symptom pat... more To explore the taxonomy of combat-related mild traumatic brain injury (mTBI) based on symptom patterns. Up to 1341 military personnel who experienced a combat-related mTBI within 2 years of evaluation. Neurobehavioral Symptom Inventory and PTSD Checklist-Civilian Version (PCL-C). Cluster analysis revealed the following 4 subtypes: primarily psychiatric (posttraumatic stress disorder) group, a cognitive group, a mixed symptom group, and a good recovery group. The posttraumatic stress disorder cluster (21.9% of the sample) reported symptoms related to hyperarousal and dissociation/depression with few complaints related to cognition or headaches. The cognitive group (21.5% of the sample) had primarily cognitive and headache complaints with few mood symptoms. The mixed profile cluster included 18.6% of the sample and was characterized by a combination of mood complaints (hyperarousal and dissociation/depression), cognitive complaints, and headaches. The largest cluster (37.8% of the sam...
Archives of Clinical Neuropsychology
Objective: Presentation of an unusual case of amnesic syndrome following a suspected AVM. The sub... more Objective: Presentation of an unusual case of amnesic syndrome following a suspected AVM. The subject was a 14-year-old female (N) who suffered a large right temporo-parietal intra-parenchymal hemorrhage with extension into the ventricular system requiring surgical evacuation. She presented with a significant anterograde amnesic disorder that was generalized and not circumscribed to the visual domain. A neuropsychological assessment was recommended to investigate the nature and extent of her amnesic symptoms. Two aspects were found to be fundamental in this case, firstly, the inconsistency between the image findings of acute cerebral injury and her general amnesic disorder, and secondly, her capacity to keep up with academic demands despite persisting memory impairment. Method: N was assessed on four occasions over a period of 4 years to monitor her recovery. The initial assessment was comprehensive and covered intellectual functions, attention, processing speed, general memory, and...
Military Medicine, 2014
The study investigated the clinical validity of the cognitive screening component of the Military... more The study investigated the clinical validity of the cognitive screening component of the Military Acute Concussion Evaluation (MACE) for the evaluation of acute mild traumatic brain injury (mTBI) in a military operational setting. This was a retrospective data study involving analysis of MACE data on Operation Enduring Freedom/Operation Iraqi Freedom deployed service members with mTBI. In total, 179 cases were included in analyses based on ICD-9 diagnostic codes and characteristics of mTBI, and availability of MACE data on day of injury. MACE data from the mTBI group was compared to a military sample without mTBI administered the MACE as part of a normative data project. On day of injury, the mTBI group performed worse than controls on the MACE cognitive test (d = 0.90), with significant impairments in all cognitive domains assessed. MACE cognitive score was strongly associated with established indicators of acute injury severity. Lower MACE cognitive performance on day of injury was predictive of lengthier postinjury recovery time and time until return to duty after mTBI. Findings from the current study support the use of the MACE as a valid screening tool to assess for cognitive dysfunction in military service members during the acute phase after mTBI.
Journal of neurotrauma, 2014
Traumatic brain injuries (TBI) sustained in combat frequently co-occur with significant bodily in... more Traumatic brain injuries (TBI) sustained in combat frequently co-occur with significant bodily injuries. Intuitively, more extensive bodily injuries might be associated with increased symptom reporting. In 2012, however, French et al. demonstrated an inverse relation between bodily injury severity and symptom reporting. This study expands on that work by examining the influence of location and severity of bodily injuries on symptom reporting after mild TBI. Participants were 579 US military service members who sustained an uncomplicated mild TBI with concurrent bodily injuries and who were evaluated at two military medical centers. Bodily injury severity was quantified using a modified Injury Severity Score (ISSmod). Participants completed the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist (PCL-C), on average, 2.5 months post-injury. There was a significant negative association between ISSmod scores and NSI (r=-0.267, p<0.001) and PCL-C (r...
Journal of neurotrauma, 2014
Explosive devices have been the most frequent cause of traumatic brain injury (TBI) among deploye... more Explosive devices have been the most frequent cause of traumatic brain injury (TBI) among deployed contemporary U.S. service members. The purpose of this study was to examine the influence of previous cumulative blast exposures (that did or did not result in TBI) on later post-concussion and post-traumatic symptom reporting after sustaining a mild TBI (MTBI). Participants were 573 service members who sustained MTBI divided into four groups by number of blast exposures (1, 2, 3, and 4-10) and a nonblast control group. Post-concussion symptoms were measured using the Neurobehavioral Symptom Inventory (NSI) and post-traumatic stress disorder (PTSD) symptoms using the Post-traumatic Checklist-Civilian version (PCL-C). Results show groups significantly differed on total NSI scores (p<0.001), where symptom endorsement increased as number of reported blast exposures increased. Total NSI scores were significantly higher for the 3- and 4-10 blast groups compared with the 1- and 2-blast gr...
Archives of Clinical Neuropsychology, 2014
The purpose of this study was to identify factors that are predictive of, or associated with, hig... more The purpose of this study was to identify factors that are predictive of, or associated with, high endorsement of postconcussion and posttraumatic stress symptoms following military-related traumatic brain injury (TBI). Participants were 1,600 U.S. service members (age: M ¼ 27.1, SD ¼ 7.1; 95.4% male) who had sustained a mild-to-moderate TBI and who had been evaluated by the Defense and Veterans Brain Injury Center at one of six military medical centers. Twenty-two factors were examined that included demographic, injury circumstances/severity, treatment/evaluation, and psychological/physical variables. Four factors were statistically and meaningfully associated with clinically elevated postconcussion symptoms: (i) low bodily injury severity, (ii) posttraumatic stress, (iii) depression, and (iv) military operation where wounded (p , .001, 43.2% variance). The combination of depression and posttraumatic stress symptoms accounted for the vast majority of unique variance (41.5%) and were strongly associated with, and predictive of, clinically elevated postconcussion symptoms [range: odds ratios (OR) ¼ 4.24-7.75; relative risk (RR) ¼ 2.28-2.51]. Five factors were statistically and meaningfully associated with clinically elevated posttraumatic stress symptoms: (i) low bodily injury severity, (ii) depression, (iii) a longer time from injury to evaluation, (iv) military operation where wounded, and (v) current auditory deficits (p , .001; 65.6% variance accounted for). Depression alone accounted for the vast majority of unique variance (60.0%) and was strongly associated with, and predictive of, clinically elevated posttraumatic stress symptoms (OR ¼ 38.78; RR ¼ 4.63). There was a very clear, strong, and clinically meaningful association between depression, posttraumatic stress, and postconcussion symptoms in this sample. Brain injury severity, however, was not associated with symptom reporting following TBI.
NeuroImage, 2012
Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian ... more Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose because the injuries are often not detectable on conventional MRI or CT. Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (ALFMA, peaked at 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We developed a new automated MEG low-frequency source imaging method and applied this method in 45 mild TBI (23 from combat-related blasts, and 22 from non-blast causes) and 10 moderate TBI patients (non-blast causes). Seventeen of the patients with mild TBI from blasts had tertiary injuries resulting from the blast. The results show our method detected abnormalities at the rates of 87% for the mild TBI group (blast-induced plus non-blast causes) and 100% for the moderate group. Among the mild TBI patients, the rates of abnormalities were 96% and 77% for the blast and non-blast TBI groups, respectively. The spatial characteristics of abnormal slow-wave generation measured by Z scores in the mild blast TBI group significantly correlated with those in non-blast mild TBI group. Among 96 cortical regions, the likelihood of abnormal slow-wave generation was less in the mild TBI patients with blast than in the mild non-blast TBI patients, suggesting possible protective effects due to the military helmet and armor. Finally, the number of cortical regions that generated abnormal slow-waves correlated significantly with the total post-concussive symptom scores in TBI patients. This study provides a foundation for using MEG low-frequency source imaging to support the clinical diagnosis of TBI.
The Journal of head trauma rehabilitation
To explore the taxonomy of combat-related mild traumatic brain injury (mTBI) based on symptom pat... more To explore the taxonomy of combat-related mild traumatic brain injury (mTBI) based on symptom patterns. Up to 1341 military personnel who experienced a combat-related mTBI within 2 years of evaluation. Neurobehavioral Symptom Inventory and PTSD Checklist-Civilian Version (PCL-C). Cluster analysis revealed the following 4 subtypes: primarily psychiatric (posttraumatic stress disorder) group, a cognitive group, a mixed symptom group, and a good recovery group. The posttraumatic stress disorder cluster (21.9% of the sample) reported symptoms related to hyperarousal and dissociation/depression with few complaints related to cognition or headaches. The cognitive group (21.5% of the sample) had primarily cognitive and headache complaints with few mood symptoms. The mixed profile cluster included 18.6% of the sample and was characterized by a combination of mood complaints (hyperarousal and dissociation/depression), cognitive complaints, and headaches. The largest cluster (37.8% of the sam...
Archives of Clinical Neuropsychology
Objective: Presentation of an unusual case of amnesic syndrome following a suspected AVM. The sub... more Objective: Presentation of an unusual case of amnesic syndrome following a suspected AVM. The subject was a 14-year-old female (N) who suffered a large right temporo-parietal intra-parenchymal hemorrhage with extension into the ventricular system requiring surgical evacuation. She presented with a significant anterograde amnesic disorder that was generalized and not circumscribed to the visual domain. A neuropsychological assessment was recommended to investigate the nature and extent of her amnesic symptoms. Two aspects were found to be fundamental in this case, firstly, the inconsistency between the image findings of acute cerebral injury and her general amnesic disorder, and secondly, her capacity to keep up with academic demands despite persisting memory impairment. Method: N was assessed on four occasions over a period of 4 years to monitor her recovery. The initial assessment was comprehensive and covered intellectual functions, attention, processing speed, general memory, and...
Military Medicine, 2014
The study investigated the clinical validity of the cognitive screening component of the Military... more The study investigated the clinical validity of the cognitive screening component of the Military Acute Concussion Evaluation (MACE) for the evaluation of acute mild traumatic brain injury (mTBI) in a military operational setting. This was a retrospective data study involving analysis of MACE data on Operation Enduring Freedom/Operation Iraqi Freedom deployed service members with mTBI. In total, 179 cases were included in analyses based on ICD-9 diagnostic codes and characteristics of mTBI, and availability of MACE data on day of injury. MACE data from the mTBI group was compared to a military sample without mTBI administered the MACE as part of a normative data project. On day of injury, the mTBI group performed worse than controls on the MACE cognitive test (d = 0.90), with significant impairments in all cognitive domains assessed. MACE cognitive score was strongly associated with established indicators of acute injury severity. Lower MACE cognitive performance on day of injury was predictive of lengthier postinjury recovery time and time until return to duty after mTBI. Findings from the current study support the use of the MACE as a valid screening tool to assess for cognitive dysfunction in military service members during the acute phase after mTBI.
Journal of neurotrauma, 2014
Traumatic brain injuries (TBI) sustained in combat frequently co-occur with significant bodily in... more Traumatic brain injuries (TBI) sustained in combat frequently co-occur with significant bodily injuries. Intuitively, more extensive bodily injuries might be associated with increased symptom reporting. In 2012, however, French et al. demonstrated an inverse relation between bodily injury severity and symptom reporting. This study expands on that work by examining the influence of location and severity of bodily injuries on symptom reporting after mild TBI. Participants were 579 US military service members who sustained an uncomplicated mild TBI with concurrent bodily injuries and who were evaluated at two military medical centers. Bodily injury severity was quantified using a modified Injury Severity Score (ISSmod). Participants completed the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist (PCL-C), on average, 2.5 months post-injury. There was a significant negative association between ISSmod scores and NSI (r=-0.267, p<0.001) and PCL-C (r...
Journal of neurotrauma, 2014
Explosive devices have been the most frequent cause of traumatic brain injury (TBI) among deploye... more Explosive devices have been the most frequent cause of traumatic brain injury (TBI) among deployed contemporary U.S. service members. The purpose of this study was to examine the influence of previous cumulative blast exposures (that did or did not result in TBI) on later post-concussion and post-traumatic symptom reporting after sustaining a mild TBI (MTBI). Participants were 573 service members who sustained MTBI divided into four groups by number of blast exposures (1, 2, 3, and 4-10) and a nonblast control group. Post-concussion symptoms were measured using the Neurobehavioral Symptom Inventory (NSI) and post-traumatic stress disorder (PTSD) symptoms using the Post-traumatic Checklist-Civilian version (PCL-C). Results show groups significantly differed on total NSI scores (p<0.001), where symptom endorsement increased as number of reported blast exposures increased. Total NSI scores were significantly higher for the 3- and 4-10 blast groups compared with the 1- and 2-blast gr...
Archives of Clinical Neuropsychology, 2014
The purpose of this study was to identify factors that are predictive of, or associated with, hig... more The purpose of this study was to identify factors that are predictive of, or associated with, high endorsement of postconcussion and posttraumatic stress symptoms following military-related traumatic brain injury (TBI). Participants were 1,600 U.S. service members (age: M ¼ 27.1, SD ¼ 7.1; 95.4% male) who had sustained a mild-to-moderate TBI and who had been evaluated by the Defense and Veterans Brain Injury Center at one of six military medical centers. Twenty-two factors were examined that included demographic, injury circumstances/severity, treatment/evaluation, and psychological/physical variables. Four factors were statistically and meaningfully associated with clinically elevated postconcussion symptoms: (i) low bodily injury severity, (ii) posttraumatic stress, (iii) depression, and (iv) military operation where wounded (p , .001, 43.2% variance). The combination of depression and posttraumatic stress symptoms accounted for the vast majority of unique variance (41.5%) and were strongly associated with, and predictive of, clinically elevated postconcussion symptoms [range: odds ratios (OR) ¼ 4.24-7.75; relative risk (RR) ¼ 2.28-2.51]. Five factors were statistically and meaningfully associated with clinically elevated posttraumatic stress symptoms: (i) low bodily injury severity, (ii) depression, (iii) a longer time from injury to evaluation, (iv) military operation where wounded, and (v) current auditory deficits (p , .001; 65.6% variance accounted for). Depression alone accounted for the vast majority of unique variance (60.0%) and was strongly associated with, and predictive of, clinically elevated posttraumatic stress symptoms (OR ¼ 38.78; RR ¼ 4.63). There was a very clear, strong, and clinically meaningful association between depression, posttraumatic stress, and postconcussion symptoms in this sample. Brain injury severity, however, was not associated with symptom reporting following TBI.
NeuroImage, 2012
Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian ... more Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose because the injuries are often not detectable on conventional MRI or CT. Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (ALFMA, peaked at 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We developed a new automated MEG low-frequency source imaging method and applied this method in 45 mild TBI (23 from combat-related blasts, and 22 from non-blast causes) and 10 moderate TBI patients (non-blast causes). Seventeen of the patients with mild TBI from blasts had tertiary injuries resulting from the blast. The results show our method detected abnormalities at the rates of 87% for the mild TBI group (blast-induced plus non-blast causes) and 100% for the moderate group. Among the mild TBI patients, the rates of abnormalities were 96% and 77% for the blast and non-blast TBI groups, respectively. The spatial characteristics of abnormal slow-wave generation measured by Z scores in the mild blast TBI group significantly correlated with those in non-blast mild TBI group. Among 96 cortical regions, the likelihood of abnormal slow-wave generation was less in the mild TBI patients with blast than in the mild non-blast TBI patients, suggesting possible protective effects due to the military helmet and armor. Finally, the number of cortical regions that generated abnormal slow-waves correlated significantly with the total post-concussive symptom scores in TBI patients. This study provides a foundation for using MEG low-frequency source imaging to support the clinical diagnosis of TBI.