Group Of Traumatic Brain Injury Patients Research Articles

Dysfunctional Timing in Traumatic Brain Injury Patients: Co-occurrence of Cognitive, Motor, and Perceptual Deficits.

Timing is an essential part of human cognition and of everyday life activities, such as walking or holding a conversation. Previous studies showed that traumatic brain injury (TBI) often affects cognitive functions such as processing speed and time-sensitive abilities, causing long-term sequelae as well as daily impairments. However, the existing evidence on timing capacities in TBI is mostly limited to perception and the processing of isolated intervals. It is therefore open whether the observed deficits extend to motor timing and to continuous dynamic tasks that more closely match daily life activities. The current study set out to answer these questions by assessing audio motor timing abilities and their relationship with cognitive functioning in a group of TBI patients (n = 15) and healthy matched controls. We employed a comprehensive set of tasks aiming at testing timing abilities across perception and production and from single intervals to continuous auditory sequences. In line with previous research, we report functional impairments in TBI patients concerning cognitive processing speed and perceptual timing. Critically, these deficits extended to motor timing: The ability to adjust to tempo changes in an auditory pacing sequence was impaired in TBI patients, and this motor timing deficit covaried with measures of processing speed. These findings confirm previous evidence on perceptual and cognitive timing deficits resulting from TBI and provide first evidence for comparable deficits in motor behavior. This suggests basic co-occurring perceptual and motor timing impairments that may factor into a wide range of daily activities. Our results thus place TBI into the wider range of pathologies with well-documented timing deficits (such as Parkinson’s disease) and encourage the search for novel timing-based therapeutic interventions (e.g., employing dynamic and/or musical stimuli) with high transfer potential to everyday life activities.

Particular features of humoral immunity in patients with acute brain concussion

Traumatic brain injury (TBI) is one of the most common neurological disorders in the world. Meanwhile, usage of neuroimaging methods does not allow precise assessment of its severity and clinical prognosis. This predetermines for searching new techniques of differential diagnosis of the TBI severity and predicting the risk of consequences. Currently, many authors have shown an association between disorders of the immune system manifesting as a decrease in general immune status, and development of cellular/humoral neurosensitization with progredient outcome of the brain injury. At the same time, the role of humoral mechanisms in pathogenesis of TBI, in particular, brain commotion, is less studied in comparison with cell-mediated mechanisms, thus suggesting a need to studying the role of activation or, vice versa, anergy of the humoral immunity in mild traumatic brain injury. The aim of this work was to study characteristics of B-lymphocyte subpopulations in peripheral blood of the patients with brain concussion (n = 22). Peripheral blood samples obtained from 52 apparently healthy volunteers served as controls. The diagnosis was made in accordance with established international criteria. In this case, the exclusion criterion were as follows: severe concomitant organ damage or somatic pathologies, as well as presence of intoxication. General examination included the collection of complaints, medical history, assessment of the somatic and neurological status. B-lymphocytes were determined using multicolor flow cytometry based on two approaches: IgD/CD38 expression (“Bm1-Bm5” classification), and IgD/CD27. We have found that the relative number of naïve Bm1 (IgD+CD38-) was significantly higher in patients with brain concussion than in conventionally healthy individuals (p 0.001). The relative content of activated naive Bm2-cells (IgD+CD38+) was significantly lower in the group of TBI patients than in controls (p 0.05). The number of naive cells (IgD+CD27-) was also significantly reduced in the brain concussion group compared to the control group. The data obtained indicate a possible significant role of B-cell immune response in pathogenesis of clinical course following the brain concussion, thus enabling assessment of possible features of humoral immune response.

Impact of timing of ventriculoperitoneal shunt placement on outcome in posttraumatic hydrocephalus.

Posttraumatic hydrocephalus (PTH) is a frequent sequela of traumatic brain injury (TBI) and complication of related cranial surgery. The roles of PTH and the timing of cerebrospinal fluid (CSF) shunt placement in TBI outcome have not been well described. The goal of this study was to assess the impact of hydrocephalus and timing of ventriculoperitoneal (VP) shunt placement on outcome during inpatient rehabilitation after TBI. In this cohort study, all TBI patients admitted to Craig Hospital between 2009 and 2013 were evaluated for PTH, defined as ventriculomegaly, and hydrocephalus symptoms, delayed or deteriorating recovery, or elevated opening pressure on lumbar puncture. Extent of ventriculomegaly was quantified by the Evans index from CT scans. Outcome measures were emergence from and duration of posttraumatic amnesia (PTA) and functional status as assessed by means of the Functional Independence Measure (FIM). Findings in this group were compared to findings in a group of TBI patients without PTH (controls) who were admitted for inpatient rehabilitation during the same study period and met specific criteria for inclusion. A total of 701 patients were admitted with TBI during the study period. Of these patients, 59 (8%) were diagnosed with PTH and were included in this study as the PTH group, and 204 who were admitted for rehabilitation and met the criteria for inclusion as controls constituted the comparison group (no-PTH group). PTH was associated with initial postinjury failure to follow commands, midline shift or cistern compression, subcortical contusion, and craniotomy or craniectomy. In multivariable analyses, independent predictors of longer PTA duration and lower FIM score at rehabilitation discharge were PTH, emergency department Glasgow Coma Scale motor score < 6, and longer time from injury to rehabilitation admission. PTH accounted for a 51-day increase in PTA duration and a 29-point reduction in discharge FIM score. In 40% of PTH patients with preshunt CT brain imaging analyzed, ventriculomegaly (Evans index > 0.3) was observed 3 or more days before VP shunt placement (median 10 days, range 3-102 days). Among PTH patients who received a VP shunt, earlier placement was associated with better outcome by all measures assessed and independently predicted better FIM total score and shorter PTA duration. Posttraumatic hydrocephalus predicts worse outcome during inpatient rehabilitation, with poorer functional outcomes and longer duration of PTA. In shunt-treated PTH patients, earlier CSF shunting predicted improved recovery. These results suggest that clinical vigilance for PTH onset and additional studies on timing of CSF diversion are warranted.

Anything goes? Regulation of the neural processes underlying response inhibition in TBI patients

Despite evidence for beneficial use of methylphenidate in response inhibition, no studies so far have investigated the effects of this drug in the neurobiology of inhibitory control in traumatic brain injury (TBI), even though impulsive behaviours are frequently reported in this patient group. We investigated the neural basis of response inhibition in a group of TBI patients using functional magnetic resonance imaging and a stop-signal paradigm. In a randomised double-blinded crossover study, the patients received either a single 30mg dose of methylphenidate or placebo and performed the stop-signal task. Activation in the right inferior frontal gyrus (RIFG), an area associated with response inhibition, was significantly lower in patients compared to healthy controls. Poor response inhibition in this group was associated with greater connectivity between the RIFG and a set of regions considered to be part of the default mode network (DMN), a finding that suggests the interplay between DMN and frontal executive networks maybe compromised. A single dose of methylphenidate rendered activity and connectivity profiles of the patients RIFG near normal. The results of this study indicate that the neural circuitry involved in response inhibition in TBI patients may be partially restored with methylphenidate. Given the known mechanisms of action of methylphenidate, the effect we observed may be due to increased dopamine and noradrenaline levels.

Disturbances of selective attention in traumatic brain injury and schizophrenia: What is common and what is different?

There are hypotheses that traumatic brain injury (TBI) and schizophrenia might exhibit similar patterns of cognitive disorders in attention, executive function and memory. Yet, empirical studies comparing directly the two populations are extremely rare. The aim of this exploratory study was to compare performance of patients with TBI and schizophrenia in a task of selective attention. A group of TBI patients (n=18), a group of patients with schizophrenia (n=21), and a control group with no history of neurologic or psychiatric illness (n=31) participated in this study. A paced paper-and-pencil cancellation task was completed by each participant, allowing for discrimination between intact and impaired attention subcomponents. Compared to the controls, both patient groups had (a) slower processing speed, (b) reduced target processing efficiency, (c) instant attentional overload, and (d) difficulties in discriminating targets from distractors. However, these deficits were of different degrees between the groups. Furthermore, (e) a marked selective impairment of processing of distractors was observed in patients with schizophrenia only, as well as (f) a failure to regulate attentional resources over time. Finally, (g) none of the groups showed any shifts in response strategies. These results suggest that there are large similarities in disturbances in selective attention between these two pathologies. Yet, whenever similar, these disturbances are of different degrees. Furthermore, there are some qualitative differences between the two pathologies.

Damage to the Salience Network and interactions with the Default Mode Network.

Interactions between the Salience Network (SN) and the Default Mode Network (DMN) are thought to be important for cognitive control. However, evidence for a causal relationship between the networks is limited. Previously, we have reported that traumatic damage to white matter tracts within the SN predicts abnormal DMN function. Here we investigate the effect of this damage on network interactions that accompany changing motor control. We initially used fMRI of the Stop Signal Task to study response inhibition in humans. In healthy subjects, functional connectivity (FC) between the right anterior insula (rAI), a key node of the SN, and the DMN transiently increased during stopping. This change in FC was not seen in a group of traumatic brain injury (TBI) patients with impaired cognitive control. Furthermore, the amount of SN tract damage negatively correlated with FC between the networks. We confirmed these findings in a second group of TBI patients. Here, switching rather than inhibiting a motor response: (1) was accompanied by a similar increase in network FC in healthy controls; (2) was not seen in TBI patients; and (3) tract damage after TBI again correlated with FC breakdown. This shows that coupling between the rAI and DMN increases with cognitive control and that damage within the SN impairs this dynamic network interaction. This work provides compelling evidence for a model of cognitive control where the SN is involved in the attentional capture of salient external stimuli and signals the DMN to reduce its activity when attention is externally focused.

A robust method for investigating thalamic white matter tracts after traumatic brain injury

Damage to the structural connections of the thalamus is a frequent feature of traumatic brain injury (TBI) and can be a key factor in determining clinical outcome. Until recently it has been difficult to quantify the extent of this damage in vivo. Diffusion tensor imaging (DTI) provides a validated method to investigate traumatic axonal injury, and can be applied to quantify damage to thalamic connections. DTI can also be used to assess white matter tract structure using tractography, and this technique has been used to study thalamo-cortical connections in the healthy brain. However, the presence of white matter injury can cause failure of tractography algorithms. Here, we report a method for investigating thalamo-cortical connectivity that bypasses the need for individual tractography. We first created a template for a number of thalamo-cortical connections using probabilistic tractography performed in ten healthy subjects. This template for investigating white matter structure was validated by comparison with individual tractography in the same group, as well as in an independent control group (N = 11). We also evaluated two methods of masking tract location using the tract skeleton generated by tract based spatial statistics, and a cerebrospinal fluid mask. Voxel-wise estimates of fractional anisotropy derived from the template were more strongly correlated with individual tractography when both types of masking were used. The tract templates were then used to sample DTI measures from a group of TBI patients (N = 22), with direct comparison performed against probabilistic tractography in individual patients. Probabilistic tractography often failed to produce anatomically plausible tracts in TBI patients. Importantly, we show that this problem increases as tracts become more damaged, and leads to underestimation of the amount of traumatic axonal injury. In contrast, the tract template can be used in these cases, allowing a more accurate assessment of white matter damage. In summary, we propose a method suitable for assessing specific thalamo-cortical white matter connections after TBI that is robust to the presence of varying amounts of traumatic axonal injury, as well as highlighting the potential problems of applying tractography algorithms in patient populations.

Identification of Binocular Vision Dysfunction (Vertical Heterophoria) in Traumatic Brain Injury Patients and Effects of Individualized Prismatic Spectacle Lenses in the Treatment of Postconcussive Symptoms: A Retrospective Analysis

To identify a form of binocular vision dysfunction (vertical heterophoria) in a traumatic brain injury (TBI) population and to assess the effect of individualized prismatic spectacle lenses on postconcussive symptoms. Retrospective study. Private physical medicine and rehabilitation practice and private optometric practice. A subset of TBI patients who were initially evaluated by a single physiatrist and who received standard treatments and medications yet had persistent postconcussive symptoms. These patients were then assessed by a single optometrist, and those found to have vertical heterophoria were treated with individualized prismatic spectacle lenses. A total of 83 patients were referred for testing; 77 were positive for vertical heterophoria on screening, of which 43 had complete data sets and were included for analysis. All patients were treated with individualized prismatic spectacle lenses to correct for vertical heterophoria. Outcomes were measured by the difference in score before and after intervention of an objective, self-administered vertical heterophoria symptom burden instrument (Vertical Heterophoria Symptom Questionnaire [VHS-Q], presently undergoing validation) and by subjective improvement in symptoms as expressed by the patient at the end of intervention. There was a 71.8% decrease in subjective symptom burden when compared with preintervention baseline. There was a mean 16.7 point absolute reduction in the VHS-Q score on a 75-point scale, which represents a relative reduction in VHS-Q score of 48.1%. Vertical heterophoria was identified in a group of TBI patients with postconcussive symptoms and treatment of the vertical heterophoria with individualized prismatic spectacle lenses resulted in a 71.8% decrease in subjective symptom burden and a relative reduction in VHS-Q score of 48.1%. It appears that vertical heterophoria can be acquired from TBI.

Six-month recovery from mild to moderate Traumatic Brain Injury: the role of APOE- 4 allele

The possession of at least one APOE-epsilon4 allele may be linked to poor outcome in patients with predominantly severe traumatic brain injury (TBI). In mild TBI, which accounts for approximately 85% of all cases, the role of the APOE-epsilon4 allele is less clear. Studies completed to date have relied on brief cognitive assessments or coarse measures of global functioning, thereby limiting their conclusions. Our study investigated the influence of the APOE-epsilon4 allele in a prospective sample of 90 adults with mild to moderate TBI in whom neuropsychiatric outcome 6 months after injury was assessed as follows: (i) a detailed neuropsychological battery; (ii) an index of emotional distress (General Health Questionnaire); (iii) a diagnosis of major depression (Structured Clinical Interview for DSM-IV); (iv) a measure of global functioning (Glasgow Outcome Scale); (v) an index of psychosocial outcome (Rivermead Head Injury Follow-up Questionnaire); and (vi) symptoms of persistent post-concussion disorder (Rivermead Post-Concussion Symptoms Questionnaire). No association was found between the presence of the APOE-epsilon4 allele and poor outcome across all measures. Given the homogeneous nature of our sample (mild to moderate injury severity), the uniform follow-up period (6 months) and the comprehensive markers of recovery used, our data suggest that the APOE-epsilon4 allele does not adversely impact outcome in this group of TBI patients.

Contribution of functional ratings to prediction of longterm employment outcome after traumatic brain injury

The present study investigated the contribution of functional ratings to prediction of employment outcome after traumatic brain injury (TBI). Previous studies have suggested that functional ratings obtained at a significant time post-injury can supplement neurologic, pre-injury, neuropsychologic, and other post-injury variables in predicting long-term employment outcome. Functional ratings studied were patients' needs for physical, cognitive, and behavioural supervision. This investigation also addressed the issue of predicting long-term outcome for the select group of TBI patients who receive post-acute brain injury rehabilitation. Subjects were 76 patients with TBI. The mean age (25th, 50th, and 75th percentiles) was 32 (22, 28, 39) years and mean premorbid education level was 13 (12, 12, 14) years. Predictors studied were severity of injury, premorbid education level, pre-injury substance use, and needs for physical, cognitive and behavioural supervision at discharge from postacute rehabilitation. Supervision needs ratings were obtained an average of 9.6 (4.2, 5.9, 11.2) months post-injury. Productivity status was assessed an average of 22.5 (12.6, 20.7, 30.5) months post-injury and 12.9 (4.9, 12.4, 16.6) months post-discharge from treatment. Spearman correlation coefficients revealed that premorbid educational level, pre-injury substance use, and needs for physical and behavioural supervision were related to long-term functional outcome (p < 0:05). However, multiple logistic regression analysis revealed that only level of pre-injury substance use was predictive of long-term productivity outcome once adjusted for the effects of the other predictors. Patients with no history of pre-injury substance use were more than eight times as likely to be employed at followup as those with a history of pre-injury substance abuse (p < 0:01).

Eye care practitioners in blood pressure related health care: Jack E. Terry, Veterans Administration Hospital, Huntington, WV

To identify a form of binocular vision dysfunction (vertical heterophoria) in a traumatic brain injury (TBI) population and to assess the effect of individualized prismatic spectacle lenses on postconcussive symptoms.Retrospective study.Private physical medicine and rehabilitation practice and private optometric practice.A subset of TBI patients who were initially evaluated by a single physiatrist and who received standard treatments and medications yet had persistent postconcussive symptoms. These patients were then assessed by a single optometrist, and those found to have vertical heterophoria were treated with individualized prismatic spectacle lenses. A total of 83 patients were referred for testing; 77 were positive for vertical heterophoria on screening, of which 43 had complete data sets and were included for analysis.All patients were treated with individualized prismatic spectacle lenses to correct for vertical heterophoria.Outcomes were measured by the difference in score before and after intervention of an objective, self-administered vertical heterophoria symptom burden instrument (Vertical Heterophoria Symptom Questionnaire [VHS-Q], presently undergoing validation) and by subjective improvement in symptoms as expressed by the patient at the end of intervention.There was a 71.8% decrease in subjective symptom burden when compared with preintervention baseline. There was a mean 16.7 point absolute reduction in the VHS-Q score on a 75-point scale, which represents a relative reduction in VHS-Q score of 48.1%.Vertical heterophoria was identified in a group of TBI patients with postconcussive symptoms and treatment of the vertical heterophoria with individualized prismatic spectacle lenses resulted in a 71.8% decrease in subjective symptom burden and a relative reduction in VHS-Q score of 48.1%. It appears that vertical heterophoria can be acquired from TBI.