Incidence of surgically treated chronic subdural hematoma after head injury with normal initial computed tomography.

PURPOSE: The objective was to determine the incidence of surgically treated chronic subdural hematoma (cSDH) within six months after head trauma in a consecutive series of head injury patients with a normal initial computed tomography (CT). METHODS: A total of 1941 adult patients with head injuries who underwent head CT within 48 h after injury and were treated at the Tampere University Hospital's emergency department were retrospectively evaluated from medical records (median age = 59 years, IQR = 39-79 years, males = 58%, patients using antithrombotic medication = 26%). Patients with no signs of acute traumatic intracranial pathology or any type of subdural collection on initial head CT were regarded as CT negative (n = 1573, 81%). RESULTS: Two (n = 2) of the 1573 CT negative patients received surgical treatment for cSDH. Consequently, the incidence of surgically treated cSDH after a normal initial head CT during a six-month follow-up was 0.13%. Both patients sustained mild traumatic brain injuries initially. One of the two patients was on antithrombotic medication (warfarin) at the time of trauma, hence incidence of surgically treated cSDH among patients with antithrombotic medication in CT negative patients (n = 376, 23.9%) was 0.27%. Additionally, within CT negative patients, one subdural hygroma was operated shortly after trauma. CONCLUSION: The extremely low incidence of surgically treated cSDH after a normal initial head CT, even in patients on antithrombotic medication, supports the notion that routine follow-up imaging after an initial normal head CT is not indicated to exclude the development of cSDH. Additionally, our findings support the concept of cSDH not being a purely head trauma-related disease.

Incidence of surgically treated post-traumatic hydrocephalus 6 months following head injury in patients undergoing acute head computed tomography.

BACKGROUND: Post-traumatic hydrocephalus (PTH) is a well-known complication of head injury. The percentage of patients experiencing PTH in trauma cohorts (0.7-51.4%) varies greatly in the prior literature depending on the study population and applied diagnostic criteria. The objective was to determine the incidence of surgically treated PTH in a consecutive series of patients undergoing acute head computed tomography (CT) following injury. METHODS: All patients (N = 2908) with head injuries who underwent head CT and were treated at the Tampere University Hospital's Emergency Department (August 2010-July 2012) were retrospectively evaluated from patient medical records. This study focused on adults (18 years or older) who were residents of the Pirkanmaa region at the time of injury and were clinically evaluated and scanned with head CT at the Tampere University Hospital's emergency department within 48 h after injury (n = 1941). A thorough review of records for neurological signs and symptoms of hydrocephalus was conducted for all patients having a radiological suspicion of hydrocephalus. The diagnosis of PTH was based on clinical and radiological signs of the condition within 6 months following injury. The main outcome was surgical treatment for PTH. Clinical evidence of shunt responsiveness was required to confirm the diagnosis of PTH. RESULTS: The incidence of surgically treated PTH was 0.15% (n = 3). Incidence was 0.08% among patients with mild traumatic brain injury (TBI) and 1.1% among those with moderate to severe TBI. All the patients who developed PTH underwent neurosurgery during the initial hospitalization due to the head injury. The incidence of PTH among patients who underwent neurosurgery for acute traumatic intracranial lesions was 2.7%. CONCLUSION: The overall incidence of surgically treated PTH was extremely low (0.15%) in our cohort. Analyses of risk factors and the evaluation of temporal profiles could not be undertaken due to the extremely small number of cases.

Reliability of the freehand region-of-interest method in quantitative cerebral diffusion tensor imaging.

BACKGROUND: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique used for evaluating changes in the white matter in brain parenchyma. The reliability of quantitative DTI analysis is influenced by several factors, such as the imaging protocol, pre-processing and post-processing methods, and selected diffusion parameters. The region-of-interest (ROI) method is most widely used of the post-processing methods because it is found in commercial software. The focus of our research was to study the reliability of the freehand ROI method using various intra- and inter-observer analyses. METHODS: This study included 40 neurologically healthy participants who underwent diffusion MRI of the brain with a 3 T scanner. The measurements were performed at nine different anatomical locations using a freehand ROI method. The data extracted from the ROIs included the regional mean values, intra- and inter-observer variability and reliability. The used DTI parameters were fractional anisotropy (FA), the apparent diffusion coefficient (ADC), and axial (AD) and radial (RD) diffusivity. RESULTS: The average intra-class correlation coefficient (ICC) of the intra-observer was found to be 0.9 (excellent). The single ICC results were excellent (> 0.8) or adequate (> 0.69) in eight out of the nine regions in terms of FA and ADC. The most reliable results were found in the frontobasal regions. Significant differences between age groups were also found in the frontobasal regions. Specifically, the FA and AD values were significantly higher and the RD values lower in the youngest age group (18-30 years) compared to the other age groups. CONCLUSIONS: The quantitative freehand ROI method can be considered highly reliable for the average ICC and mostly adequate for the single ICC. The freehand method is suitable for research work with a well-experienced observer. Measurements should be performed at least twice in the same region to ensure that the results are sufficiently reliable. In our study, reliability was slightly undermined by artifacts in some regions such as the cerebral peduncle and centrum semiovale. From a clinical point of view, the results are most reliable in adults under the age of 30, when age-related changes in brain white matter have not yet occurred.

Preexisting conditions in older adults with mild traumatic brain injuries.

OBJECTIVE: This study examined the prevalence of preexisting conditions that could affect premorbid brain health, cognition, and functional independence among older adults with mild traumatic brain injury (MTBI), and the relationship between preexisting conditions, injury characteristics, and emergency department (ED) discharge location (home versus continued care). METHODS: Older adults (N = 1,427; 55-104 years-old; 47.4% men) who underwent head computed tomography (CT) after acute head trauma were recruited from the ED. Researchers documented preexisting medical conditions retrospectively from hospital records. RESULTS: Multiple preexisting conditions increased in frequency with greater age, including circulatory and nervous system diseases and preexisting abnormalities on head CT. Psychiatric and substance use disorders (SUDs) decreased in frequency with greater age. Among participants with uncomplicated MTBI and GCS = 15, preexisting nervous system diseases and preexisting CT abnormalities were associated with higher odds of continued care for all participants, whereas psychiatric disorders and SUDs were only associated with higher odds of continued care among participants <70 years-old. Preexisting circulatory diseases, loss of consciousness, and amnesia were unassociated with discharge location. CONCLUSIONS: Preexisting medical conditions that could affect brain and cognitive health occur commonly among older adults who sustain MTBIs. These conditions can confound research examining post-injury outcomes within this age group.

Long-term excess mortality after chronic subdural hematoma.

OBJECTIVE: To assess possible long-term excess mortality and causes of death of patients with chronic subdural hematoma (CSDH). METHODS: A retrospective study (1990-2015) of adult patients (n = 1133, median age = 76 years old, men = 65%) with CSDH identified by ICD-codes and verified by medical records. All patients were followed until death or the end of 2017. Cumulative relative survival ratios and relative excess risks of death (RER) were estimated by comparing patients' mortality with that in the entire regional matched population. The causes of death were compared with a separate reference group formed by randomly choosing sex, age, and calendar time matched controls (4 controls per each CSDH patient). RESULTS: The median follow-up time was 4.8 years (range = 0-27 years), and 710 (63%) of the patients died (median age at death = 84 years old). The cumulative excess mortality was 1 year = 9%, 5 years = 18%, 10 years = 27%, 15 years = 37%, and 20 years = 48%. A subgroup of CSDH patients (n = 206) with no comorbidity had no excess mortality. Excess mortality was related to poor modified Rankin score at admission (RER = 4.93) and at discharge (RER = 8.31), alcohol abuse (RER = 4.47), warfarin (RER = 2.94), age ≥ 80 years old (RER = 1.83), non-operative treatment (RER = 1.56), and non-traumatic etiology (RER = 1.69). Hematoma characteristics or recurrence were unrelated to excess mortality. Dementia was the most common cause of death among the CSDH patients (21%) and the third most common cause in the reference group (15%, p < 0.001). CONCLUSIONS: Patients with CSDH have continuous excess mortality up to 20 years after diagnosis. Patient-related characteristics have a strong association with excess mortality, whereas specific CSDH-related findings do not. CSDH patients have an increased risk for dementia-related mortality.

Chronic subdural hematoma-incidence, complications, and financial impact.

OBJECTIVE: To examine the population-based incidence, complications, and total, direct hospital costs of chronic subdural hematoma (CSDH) treatment in a neurosurgical clinic during a 26-year period. The aim was also to estimate the necessity of planned postoperative follow-up computed tomography (CT). METHODS: A retrospective cohort (1990-2015) of adult patients living in Pirkanmaa, Finland, with a CSDH was identified using ICD codes and verified by medical records (n = 1148, median age = 76 years, men = 65%). Data collection was performed from medical records. To estimate the total, direct hospital costs, all costs from hospital admission until the last neurosurgical follow-up visit were calculated. All patients were followed until death or the end of 2017. The annual number of inhabitants in the Pirkanmaa Region was obtained from the Statistics Finland (Helsinki, Finland). RESULTS: The incidence of CSDH among the population 80 years or older has increased among both operatively (from 36.6 to 91/100,000/year) and non-operatively (from 4.7 to 36.9/100,000/year) treated cases. Eighty-five percent (n = 978) underwent surgery. Routine 4-6 weeks' postoperative follow-up CT increased the number of re-operations by 18% (n = 49). Most of the re-operations (92%) took place within 2 months from the primary operation. Patients undergoing re-operations suffered more often from seizures (10%, n = 28 vs 3.9%, n = 27; p < 0.001), empyema (4.3%, n = 12 vs 1.1%, n = 8; p = 0.002), and pneumonia (4.7%, n = 13 vs 1.4%, n = 12; p = 0.008) compared with patients with no recurrence. The treatment cost for recurrent CSDHs was 132% higher than the treatment cost of non-recurrent CSDHs, most likely because of longer hospital stay for re-admissions and more frequent outpatient follow-up with CT. The oldest group of patients, 80 years or older, was not more expensive than the others, nor did this group have more frequent complications, besides pneumonia. CONCLUSIONS: Based on our population-based study, the number of CSDH patients has increased markedly during the study period (1990-2015). Reducing recurrences is crucial for reducing both complications and costs. Greater age was not associated with greater hospital costs related to CSDH. A 2-month follow-up period after CSDH seems sufficient for most, and CT controls are advocated only for symptomatic patients.

Reliability of serum S100B measurement following mild traumatic brain injury: a comparison of assay measurements from two laboratories.

OBJECTIVE: There is enormous research and clinical interest in blood-based biomarkers of mild traumatic brain injury (MTBI) sustained in sports, daily life, or military service. We examined the reliability of a commercially available assay for S100B used on the same samples by two different laboratories separated by 2 years in time. METHODS AND PROCEDURES: A cohort of 163 adult patients (head CT-scanned, n = 110) with mild head injury were enrolled from the emergency department (ED). All had Glasgow Coma Scale scores of 14 or 15 in the ED (94.4% = 15). The mean time between injury and venous blood sampling was 2.9 h (SD = 1.4; Range = 0.5-6.0 h). Serum S100B was measured at two independent centers using the same high throughput clinical assay (Elecsys S100B®; Roche Diagnostics). RESULTS: The Spearman correlation between the two assays in the total sample (N = 163) was r = 0.93. A Wilcoxson Signed Ranks test indicated that the median scores for the values differed (Z = 2,082, p < .001, Cohen's d = 0.151, small effect size). The values obtained from the two laboratories were very similar for identifying traumatic intracranial abnormalities (sensitivity = 80.1% versus 85.7%). CONCLUSIONS: The serum S100B results measured using the same assay in different laboratories yielded highly correlated and clinically similar, but clearly not identical, results.

Violence-related traumatic brain injury.

Objectives: The purpose of this study was to determine the unique characteristics of violence-related traumatic brain injuries (TBI). Methods: All consecutive patients who underwent head CT due to an acute head injury (n = 3023) at the Emergency Department of Tampere University Hospital (Aug 2010-Jul 2012) were included. A detailed retrospective data collection was conducted in relation to demographics, injury-related data, premorbid health, clinical characteristics, and neuroimaging findings. Results: Patients with violence-related TBIs (n = 222) were compared to patients who sustained a TBI by other mechanisms (n = 2801). Statistically significant differences were found on age, gender, prior circulatory system disease, prior mental or behavioral disorders, chronic alcohol abuse, regular substance abuse, regular medication, alcohol intoxication at the time of injury, narcotics intoxication at the time of injury, and acute traumatic lesion on head CT. The groups did not differ on clinical signs of TBI severity. Conclusions: Young adult males with premorbid mental health history and chronic alcohol abuse are most prone to sustain a TBI due to a violence-related incident. Incidents are often related to alcohol intoxication. However, violence was not consistently associated with more severe TBIs than other mechanisms of injury.

Successful management of super-refractory status epilepticus with thalamic deep brain stimulation.

Super-refractory status epilepticus is a condition characterized by recurrence of status epilepticus despite use of deep general anesthesia, and it has high morbidity and mortality rates. We report a case of a 17-year-old boy with a prolonged super-refractory status epilepticus that eventually resolved after commencing deep brain stimulation of the centromedian nucleus of the thalamus. Later attempt to reduce stimulation parameters resulted in immediate relapse of status epilepticus, suggesting a pivotal role of deep brain stimulation in the treatment response. Deep brain stimulation may be a treatment option in super-refractory status epilepticus when other treatment options have failed. ANN NEUROL 2017;81:142-146.

Procedural complications of endovascular treatment in patients with aneurysmal subarachnoid haemorrhage treated at a single centre.

BACKGROUND: We present a single-centre experience of procedural complications suffered by patients undergoing endovascular treatment for a ruptured saccular intracranial aneurysm at Tampere University Hospital, Finland, between 2000 and 2014. METHOD: From 2000 to 2014, we treated 1,253 patients with aneurysmal subarachnoid haemorrhage, 491 of whom received endovascular treatment. Clinical data were collected retrospectively from the hospital's aneurysm database. A procedural complication was defined as having occurred whenever there was a documented new event in the patient's medical records or a note of a technical complication written by an interventionist after endovascular treatment. Procedural complications could be with or without clinical symptoms. RESULTS: Nearly 40% (491/1253) of the patients were treated with the endovascular method. Procedural complications occurred in 11.4% (56/491) of cases. The morbidity rate was 4.5% (22/491) and the mortality rate was 0.2% (1/491). Of the 56 complications, ischaemic complications occurred in 52% (29/56), haemorrhagic complications occurred in 27% (15/56) and technical complications occurred in 21% (12/56) of cases. In 61% (34/56) of the cases, the procedural complication did not cause any clinical symptoms. CONCLUSIONS: The total risk for procedural complications leading to postoperative disability or death at our institute was 4.7%. The complication frequency is in accordance with previous reports. Endovascular treatment of ruptured intracranial aneurysms is a safe treatment method when patient selection is carefully performed.

Causal Evidence from Humans for the Role of Mediodorsal Nucleus of the Thalamus in Working Memory.

The mediodorsal nucleus of the thalamus (MD), with its extensive connections to the lateral pFC, has been implicated in human working memory and executive functions. However, this understanding is based solely on indirect evidence from human lesion and imaging studies and animal studies. Direct, causal evidence from humans is missing. To obtain direct evidence for MD's role in humans, we studied patients treated with deep brain stimulation (DBS) for refractory epilepsy. This treatment is thought to prevent the generalization of a seizure by disrupting the functioning of the patient's anterior nuclei of the thalamus (ANT) with high-frequency electric stimulation. This structure is located superior and anterior to MD, and when the DBS lead is implanted in ANT, tip contacts of the lead typically penetrate through ANT into the adjoining MD. To study the role of MD in human executive functions and working memory, we periodically disrupted and recovered MD's function with high-frequency electric stimulation using DBS contacts reaching MD while participants performed a cognitive task engaging several aspects of executive functions. We hypothesized that the efficacy of executive functions, specifically working memory, is impaired when the functioning of MD is perturbed by high-frequency stimulation. Eight participants treated with ANT-DBS for refractory epilepsy performed a computer-based test of executive functions while DBS was repeatedly switched ON and OFF at MD and at the control location (ANT). In comparison to stimulation of the control location, when MD was stimulated, participants committed 2.26 times more errors in general (total errors; OR = 2.26, 95% CI [1.69, 3.01]) and 2.86 times more working memory-related errors specifically (incorrect button presses; OR = 2.88, CI [1.95, 4.24]). Similarly, participants committed 1.81 more errors in general ( OR = 1.81, CI [1.45, 2.24]) and 2.08 times more working memory-related errors ( OR = 2.08, CI [1.57, 2.75]) in comparison to no stimulation condition. "Total errors" is a composite score consisting of basic error types and was mostly driven by working memory-related errors. The facts that MD and a control location, ANT, are only few millimeters away from each other and that their stimulation produces very different results highlight the location-specific effect of DBS rather than regionally unspecific general effect. In conclusion, disrupting and recovering MD's function with high-frequency electric stimulation modulated participants' online working memory performance providing causal, in vivo evidence from humans for the role of MD in human working memory.

Spinal cord injury induces widespread chronic changes in cerebral white matter.

Traumatic spinal cord injuries (SCIs) lead to axonal damage at the trauma site, as well as disconnections within the central nervous system. While the exact mechanisms of the long-term pathophysiological consequences of SCIs are not fully understood, it is known that neuronal damage and degeneration are not limited to the direct proximity of the trauma. Instead, the effects can be detected even in the cerebrum. We examined SCI-induced chronic brain changes with a case-control design using 32 patients and 70 control subjects. Whole-brain white matter (WM) tracts were assessed with diffusion tensor imaging (DTI). In addition, we analysed associations between DTI metrics and several clinical SCI variables. Whole-brain analyses were executed by tract-based spatial statistics (TBSS), with an additional complementary atlas-based analysis (ABA). We observed widespread, statistically significant (P ≤ 0.01) changes similar to neural degeneration in SCI patients, both in the corticospinal tract (CST) and beyond. In addition, associations between DTI metrics and time since injury were found with TBSS and ABA, implying possible long-term post-injury neural regeneration. Using the ABA approach, we observed a correlation between SCI severity and DTI metrics, indicating a decrease in WM integrity along with patient sensory or motor scores. Our results suggest a widespread neurodegenerative effect of SCI within the cerebrum that is not limited to the motor pathways. Furthermore, DTI-measured WM integrity of chronic SCI patients seemed to improve as time elapsed since injury. Hum Brain Mapp 38:3637-3647, 2017. © 2017 Wiley Periodicals, Inc.

Head injuries and the risk of concurrent cervical spine fractures.

BACKGROUND: Cervical spine injuries of variable severity are common among patients with an acute traumatic brain injury (TBI). We hypothesised that TBI patients with positive head computed tomography (CT) scans would have a significantly higher risk of having an associated cervical spine fracture compared to patients with negative head CT scans. METHOD: This widely generalisable retrospective sample was derived from 3,023 consecutive patients, who, due to an acute head injury (HI), underwent head CT at the Emergency Department of Tampere University Hospital (August 2010-July 2012). Medical records were reviewed to identify the individuals whose cervical spine was CT-imaged within 1 week after primary head CT due to a clinical suspicion of a cervical spine injury (CSI) (n = 1,091). RESULTS: Of the whole cranio-cervically CT-imaged sample (n = 1,091), 24.7% (n = 269) had an acute CT-positive TBI. Car accidents 22.4% (n = 244) and falls 47.8% (n = 521) were the most frequent injury mechanisms. On cervical CT, any type of fracture was found in 6.6% (n = 72) and dislocation and/or subluxation in 2.8% (n = 31) of the patients. The patients with acute traumatic intracranial lesions had significantly (p = 0.04; OR = 1.689) more cervical spine fractures (9.3%, n = 25) compared to head CT-negative patients (5.7%, n = 47). On an individual cervical column level, head CT positivity was especially related to C6 fractures (p = 0.031, OR = 2.769). Patients with cervical spine fractures (n = 72) had altogether 101 fractured vertebrae, which were most often C2 (22.8, n = 23), C7 (19.8%, n = 20) and C6 (16.8%, n = 17). CONCLUSIONS: Head trauma patients with acute intracranial lesions on CT have a higher risk for cervical spine fractures in comparison to patients with a CT-negative head injury. Although statistically significant, the difference in fracture rate was small. However, based on these results, we suggest that cervical spine fractures should be acknowledged when treating CT-positive TBIs.

Regional differences in the incidence of aneurysmal subarachnoid haemorrhage in Finland.

BACKGROUND: Over the years, the consensus has generally been that Finland is a country with a significantly high incidence of aneurysmal subarachnoid haemorrhage (SAH) when compared to the rest of the world, excluding Japan. Most of the traditionally cited Finnish incidence studies are several decades old and have clear differences in their methodology and study design. The objective of this study was to determine the hospital-admitted incidence of aneurysmal SAH at Tampere University Hospital between 1990 and 2014. We also compared the incidence to other geographical regions in Finland. METHODS: The material for this study consists of patients admitted to Tampere University Hospital between 1990 and 2014 with the presentation of aneurysmal SAH. There was a total of 1965 patients with aneurysmal SAH in our data. RESULTS: The mean hospital-admitted aneurysmal SAH incidence over the period was 7.41 per 100,000 person-years. The hospital-admitted aneurysmal SAH incidence in the Eastern Finland region was two-thirds greater than in the Tampere University Hospital region. CONCLUSIONS: We observed a relatively steady hospital-admitted incidence of aneurysmal SAH (7.41 per 100,000 person-years) in the Tampere University Hospital region. This result is parallel to a recent study looking into the incidence of aneurysmal SAH for the whole of Finland. Compared to the Tampere University Hospital region, the incidence was 64% greater in the Eastern Finland region.

The Correlation between Intraoperative Microelectrode Recording and 3-Tesla MRI in Patients Undergoing ANT-DBS for Refractory Epilepsy.

BACKGROUND: Deep brain stimulation (DBS) of the anterior nucleus of the thalamus) (ANT) has been suggested as a treatment option in refractory epilepsy. The targeting of ANT is especially challenging due to its poor visualization in commonly used MRI sequences, lack of easily observable symptom relief during surgery and high degree of anatomical variation between individuals. OBJECTIVES: To study whether intraoperative microelectrode recording (MER), a method widely used in movement disorder surgery, provides clinically relevant information during the ANT-DBS implantation procedure. METHODS: A total of 186 MER samples from 5 patients and 10 thalami obtained from ANT-DBS surgery for refractory epilepsy were analyzed with respect to the signal characteristics and location in 3-tesla (3T) MRI STIR (short T1 inversion recovery) images. The location of each MER sample was calculated relative to visible borders of the ANT after correction of the sample locations according to the position of the final DBS electrode in postoperative CT-MRI fusion images. RESULTS: We found that the lateral aspect of the ANT lacked spiking activity consistent with the presence of white matter. The spike frequency in samples correlating with location at the ANT showed significantly lower spike frequency compared to samples correlating with location at the ventral anterior nucleus (median 3.0 and 7.0 spikes/2 s; p < 0.05), but spike bursts were morphologically similar in appearance. Trajectories entering the dorsomedial nucleus according to 3T MRI STIR images showed a yet different firing pattern with more low-amplitude regular activity. CONCLUSIONS: Our data suggest that MER provides clinically relevant information during implantation surgery by demonstrating both nucleus-specific neuronal firing patterns and white matter laminae between different nuclear groups.

Imaging of Anterior Nucleus of Thalamus Using 1.5T MRI for Deep Brain Stimulation Targeting in Refractory Epilepsy.

BACKGROUND: Deep brain stimulation (DBS) of the anterior nucleus of thalamus (ANT) is an evolving treatment option in refractory focal epilepsy. Due to poor visualization of ANT in traditional MRI sequences used for movement disorder surgery, targeting of ANT is mainly based on stereotactic atlas information. Sophisticated 3T MRI methods enable visualization of ANT, but 1.5T MRI is still preferred or more readily available in a large number of centers performing DBS. OBJECTIVE: In the present study, we sought to determine whether ANT could be adequately visualized at 1.5T MRI pre- and postoperatively using imaging techniques similar to the ones visualizing ANT in 3T MRI. A total of 15 MRI examinations with short tau inversion recovery (STIR) and T1-weighted magnetization prepared gradient echo (MPRAGE) images were performed to visualize ANT in nonepileptic subjects (n = 2), patients with vagus nerve stimulator (VNS) (n = 3), stereotactic MRI (n = 3), patients with ANT-DBS (n = 7). RESULTS: ANT was distinctly visualized in STIR and T1-weighted MPRAGE images in patients without implanted stimulators, with Leksell stereotactic frame and with fully implanted VNS. Postoperative 1.5T MRI was able to demonstrate some of the anatomical landmarks around ANT enabling assessment of electrode contact locations. CONCLUSIONS: The visualization of ANT is possible in preoperative 1.5T MRI enabling direct targeting of ANT all examined situations. The use of indirect targeting and its inherent potential for lead misplacement due to anatomical variation may be avoided using these MRI methods. Furthermore, postoperative MRI with STIR and T1-weighted MPRAGE images enable detailed postoperative assessment of contact locations.

Bacterial DNA findings in ruptured and unruptured intracranial aneurysms.

OBJECTIVE: Chronic inflammation has earlier been detected in ruptured intracranial aneurysms. A previous study detected both dental bacterial DNA and bacterial-driven inflammation in ruptured intracranial aneurysm walls. The aim of this study was to compare the presence of oral and pharyngeal bacterial DNA in ruptured and unruptured intracranial aneurysms. The hypothesis was that oral bacterial DNA findings would be more common and the amount of bacterial DNA would be higher in ruptured aneurysm walls than in unruptured aneurysm walls. MATERIALS AND METHODS: A total of 70 ruptured (n = 42) and unruptured (n = 28) intracranial aneurysm specimens were obtained perioperatively in aneurysm clipping operations. Aneurysmal sac tissue was analysed using a real-time quantitative polymerase chain reaction to detect bacterial DNA from several oral species. Both histologically non-atherosclerotic healthy vessel wall obtained from cardiac by-pass operations (LITA) and arterial blood samples obtained from each aneurysm patient were used as control samples. RESULTS: Bacterial DNA was detected in 49/70 (70%) of the specimens. A total of 29/42 (69%) of the ruptured and 20/28 (71%) of the unruptured aneurysm samples contained bacterial DNA of oral origin. Both ruptured and unruptured aneurysm tissue samples contained significantly more bacterial DNA than the LITA control samples (p-values 0.003 and 0.001, respectively). There was no significant difference in the amount of bacterial DNA between the ruptured and unruptured samples. CONCLUSION: Dental bacterial DNA can be found using a quantitative polymerase chain reaction in both ruptured and unruptured aneurysm walls, suggesting that bacterial DNA plays a role in the pathogenesis of cerebral aneurysms in general, rather than only in ruptured aneurysms.

Acute mild traumatic brain injury is not associated with white matter change on diffusion tensor imaging.

This study was designed to (i) evaluate the influence of age on diffusion tensor imaging measures of white matter assessed using tract-based spatial statistics; (ii) determine if mild traumatic brain injury is associated with microstructural changes in white matter, in the acute phase following injury, in a large homogenous sample that was carefully screened for pre-injury medical, psychiatric, or neurological problems; and (iii) examine if injury severity is related to white matter changes. Participants were 75 patients with acute mild traumatic brain injury (age = 37.2 ± 12.0 years, 45 males and 30 females) and 40 controls (age = 40.6 ± 12.2 yrs, 20 males and 20 females). Age effects were analysed by comparing control subgroups aged 31-40, 41-50, and 51-60 years against a group of 18-30-year-old control subjects. Widespread statistically significant areas of abnormal diffusion tensor measures were observed in older groups. Patients and controls were compared using age and gender as covariates and in age- and gender-matched subgroups. Subgroups of patients with more severe injuries were compared to age-and gender-matched controls. No significant differences were detected in patient-control or severity analyses (all P-value > 0.01). In this large, carefully screened sample, acute mild traumatic brain injury was not associated with diffusion tensor imaging abnormalities detectable with tract-based spatial statistics.

Resilience is associated with fatigue after mild traumatic brain injury.

OBJECTIVE: To examine resilience as a predictor of change in self-reported fatigue after mild traumatic brain injury (MTBI). PARTICIPANTS: A consecutive series of 67 patients with MTBI and 34 orthopedic controls. DESIGN: Prospective longitudinal study. MAIN MEASURES: Resilience Scale, Beck Depression Inventory-Second Edition, and Pain subscale from Ruff Neurobehavioral Inventory 1 month after injury and Barrow Neurological Institute Fatigue Scale 1 and 6 months after injury. RESULTS: Insomnia, pain, and depressive symptoms were significantly correlated with fatigue, but even when these variables were controlled for, resilience significantly predicted the change in fatigue from 1 to 6 months after MTBI. In patients with MTBI, the correlation between resilience and fatigue strengthened during follow-up. In controls, significant associations between resilience and fatigue were not found. CONCLUSION: Resilience is a significant predictor of decrease in self-reported fatigue following MTBI. Resilience seems to be a relevant factor to consider in the management of fatigue after MTBI along with the previously established associated factors (insomnia, pain, and depressive symptoms).

Clinical correlates of retrograde amnesia in mild traumatic brain injury.

PRIMARY OBJECTIVE: The purpose of this study was to examine the clinical significance of retrograde amnesia (RA) in patients with acute mild traumatic brain injuries (MTBI). METHODS AND PROCEDURES: An emergency department sample of patients (n = 75), aged 18-60 years, with no pre-morbid medical or psychiatric conditions, who met the WHO criteria for MTBI were enrolled in this prospective, descriptive, follow-up study. This study examined the presence and duration of RA in relation to socio-demographics, MTBI severity markers including neuroimaging (CT, MRI) and clinical outcomes (Rivermead post-concussion symptoms questionnaire, post-concussion syndrome (PCS) diagnosis and return to work (RTW) status) at 2 weeks, 1 month and 6 months post-injury. MAIN OUTCOMES AND RESULTS: GCS scores and duration of post-traumatic amnesia (PTA) were related to RA. Those with GCS scores of 14 vs. 15 were more likely to have RA (χ(2)(1) = 13.70, p < 0.0001) and a longer duration (Mann-Whitney U = 56.0, p < 0.0001, d = 1.15) of RA. The duration of RA and PTA correlated positively (Spearman ρ(75) = 0.42, p < 0.0001) and those with RA had longer durations of PTA (Mann-Whitney U = 228.5, p = 0.001, d = 1.21). During the follow-up, the presence and duration of RA were not significantly associated with PCS diagnosis or time to RTW. CONCLUSIONS: In this study, the presence and duration of RA was not associated with outcome.