The effect of repeated concussions on clinical and neurocognitive symptom severity in different contact sports

INTRODUCTION

The potential consequences of repeated concussions in sport are well documented. However, it remains unclear whether the cumulative impact of sports-related concussions differs between different contact sports. Therefore, the aim of the current study was to investigate the cumulative effects of sports-related concussions on clinical and neurocognitive health in different contact sports.

MATERIALS AND METHODS

In a prospective multicenter study, we examined 507 (74 females) active professional athletes between 18 and 40 years of age from five different contact sports (soccer, handball, American football, basketball, and ice hockey). Data collection involved concussion history, clinical symptom evaluation, neurocognitive assessment, and the collection of other sports-related information. Composite scores were built for clinical symptoms (such as neck pain and balance disturbances) and for neurocognitive symptoms (such as memory and attention impairments).

RESULTS

Athletes having suffered 3+ concussions in the past showed disproportionally higher clinical symptom severity than athletes with less than three concussions across all sports. The level of clinical symptom burden in athletes with 3+ concussions indicated mild impairment. The number of past concussions did not affect neurocognitive performance.

DISCUSSION

Repeated sports-related concussions appear to have a cumulative impact on clinical-but not cognitive-symptom severity. Although clinical symptom burden in athletes with 3+ concussions in the past was not alarmingly high yet in our sample, increased caution should be advised at this point. Despite few exceptions, results are similar for different contact sports, suggesting a similar multidisciplinary concussion management across all types of sport.

Do depressed patients really over-report cognitive impairment?

BACKGROUND

Depressed patients report more severe cognitive impairment than is detectable by neuropsychological tests because they may underestimate their cognitive performance. Alternatively, it is possible that cognitive impairment primarily occurs under everyday life conditions as referred to in most questionnaires. The aim of the present study is to investigate the validity of self-reports in patients with major depression in order to better understand the pronounced impairment in self-reports.

METHODS

We investigated 58 patients with major depression and 28 heathy control participants. We administered the "Screen for Cognitive Impairment in Psychiatry" (SCIP) to assess cognitive performance, the "Questionnaire for Cognitive Complaints" (FLei), and the newly developed scale for "Self-Perception of Cognitive Performance in everyday life and test settings" to ask for the self-assessed cognitive performance in everyday life and in a test situation more specifically.

RESULTS

Depressed patients showed an inferior test performance and reported much more general everyday life related cognitive problems compared to healthy participants. When asked more specifically for their cognitive performance in the test-situation compared to others and compared to everyday life, they did not report more test-related and everyday life related impairment than healthy participants did.

LIMITATIONS

Results might be influenced by comorbidity.

CONCLUSIONS

These results have implications for the assessment of subjective cognitive performance of depressed patients and shed light on the negative effects of general versus more specific recall of autobiographical information.

Overestimation of on-road driving performance is associated with reduced driving safety in older drivers

OBJECTIVES

Older drivers often show less precise self-ratings with a tendency to overestimate themselves. It is unclear, however, how overestimators differ from underestimators or drivers with adequate self-ratings.

METHODS

59 healthy older drivers participated in this on-road study. Besides standardized on-road driving assessment, the study protocol included the collection of neuropsychological and driving-related data as well as different self-ratings. Statistical analyses involved correlations between different subjective and objective ratings as well as statistical comparisons between drivers who overestimated and drivers who adequately rated their on-road driving performance (no drivers underestimated their performance).

RESULTS

Despite positive correlations between different self- and expert ratings, our results revealed that 25 % of the participants overestimated their on-road driving skills. Among other things, overestimators showed poorer on-road driving performances, more prospective near and minor at-fault accidents, poorer cognitive performances in specific driving-related domains and reduced annual mileage.

DISCUSSION

Our results suggest that older drivers who overestimate their driving skills show poorer performances within a broad range of skills that directly reflect or are closely related to driving safety. Against the background that an adequate self-assessment is required by German traffic regulations, our findings suggest that overestimators represent a risk group among the population of older drivers.

Give me a sign: Concrete symbols facilitate orientation in Alzheimer's disease dementia

OBJECTIVES

Persons with Alzheimer's disease dementia (ADD) often show impaired orientation particularly in unknown environments. Signs may offer an opportunity to compensate for these deficits and thus improve participation.

METHOD

We assessed 30 persons with ADD and 36 healthy controls by using a Sign Comprehension Paradigm (SCP) in a real-life like environment. Nonparametric mixed model analyses of variance were used to analyze the effect of different symbols and additional scripture (coding condition) on SCP performance speed and accuracy.

RESULTS

Analyses revealed a significant main effect of symbol design on SCP speed as well as an interaction effect of group*symbol, indicating a benefit of concrete, optimized signs for persons with ADD. Furthermore, analyses of SCP error rates revealed main effects of group and coding condition as well as an interaction effect of group*coding. Persons with ADD made more errors than healthy controls, but SCP error rates decreased significantly in ADD in the double-coding condition.

DISCUSSION

Our findings revealed an advantage of concrete double-coded symbols over conventional symbols and therefore strongly suggest the implementation of concrete double-coded signs to support older people living with ADD.

A retrospective multicentre cohort study of the performances on attention tests in outpatients with cognitive dysfunctions without delirium

OBJECTIVE

Attention is the cardinal feature of delirium, but attentional domains may also be affected by dementia and its severity. It is, therefore, of interest to study the correlation between the severity of cognitive impairment in non-delirious patients and different measurements of attentional performance, to identify attention subdomains less affected by severity of cognitive impairment.

METHODS

Neuropsychological data from non-delirious outpatients (age ≥ 65 years), presenting at two memory clinics were analysed retrospectively. Scores for selective, divided, and sustained attention were correlated with cognitive impairment as defined by the score of the Mini-Mental State Examination.

RESULTS

A total of 1658 outpatients were included. The mean age was 77.15 (± 8.17) years, with a mean MMSE score of 22.67 (± 4.91). Compared to the type of attention, the tests that are less influenced by the severity of cognitive impairment are those of selective attention, in particular the Digit Span Forward (DSF).

CONCLUSIONS

This is the first study to correlate deficits in attention subdomains with the degree of cognitive impairment in non-delirious patients. The results suggest that measurements of selective attention (i.e. DSF) might be better suited to discriminate delirium from dementia. Indeed, a lower score on these tests might be indicative of an acute change and worsening of the baseline inattention and a longitudinal monitoring of these changes might be used to determine the delirium resolution.

Impaired Color Discrimination in Alzheimer Disease Dementia

OBJECTIVE

Patients with Alzheimer disease dementia (ADD) often show impaired orientation and navigation. Signage offers an opportunity to compensate for these deficits, communicate information efficiently and facilitate wayfinding. Certain properties of signs such as colors and contrasts may beneficially affect the uptake and processing of information particularly in ADD patients.

METHODS

Thirty-six healthy older adults and 30 ADD patients performed a computerized color perception task that required discriminating different color combinations. The effects of different contrast features on performance accuracy and speed in the 2 experimental groups were examined by nonparametric mixed analysis of variances.

RESULTS

Analyses revealed a significant effect of contrast polarity on reaction times, significant effects of group on reaction times and errors as well as a marginally significant interaction of group×color on errors. All participants benefitted from positive contrast polarity (ie, dark target on lighter background) as indicated by increased performance speed. Furthermore, ADD patients reacted slower and less accurate than healthy controls, but showed higher accuracy at black-white and red-yellow than at blue-green color combinations.

CONCLUSIONS

Our findings suggest the implementation of signs with positive contrast polarity to ensure faster reactions. In addition, certain color combinations may enhance accuracy, particularly in patients with ADD.

Neural correlates of emotion acceptance and suppression in borderline personality disorder

BACKGROUND

Emotion dysregulation is a central feature of borderline personality disorder (BPD). Since impaired emotion regulation contributes to disturbed emotion functioning in BPD, it is crucial to study underlying neural activity. The current study aimed at investigating the neural correlates of two emotion regulation strategies, namely emotion acceptance and suppression, which are both important treatment targets in BPD.

METHODS

Twenty-one women with BPD and 23 female healthy control participants performed an emotion regulation task during functional magnetic resonance imaging (fMRI). While watching fearful movie clips, participants were instructed to either accept or to suppress upcoming emotions compared to passive viewing.

RESULTS

Results revealed acceptance-related insular underactivation and suppression-related caudate overactivation in subjects with BPD during the emotion regulation task.

CONCLUSION

This is a first study on the neural correlates of emotion acceptance and suppression in BPD. Altered insula functioning during emotion acceptance may reflect impairments in emotional awareness in BPD. Increased caudate activity is linked to habitual motor and cognitive processes and therefore may accord to the well-established routine in BPD patients to suppress emotional experiences.

Predicting On-Road Driving Skills, Fitness to Drive, and Prospective Accident Risk in Older Drivers and Drivers with Mild Cognitive Impairment: The Importance of Non-Cognitive Risk Factors

BACKGROUND

On-road driving behavior can be impaired in older drivers and particularly in drivers with mild cognitive impairment (MCI).

OBJECTIVE

To determine whether cognitive and non-cognitive risk factors for driving safety may allow an accurate and economic prediction of on-road driving skills, fitness to drive, and prospective accident risk in healthy older drivers and drivers with MCI, we examined a representative combined sample of older drivers with and without MCI (N = 74) in an observational on-road study. In particular, we examined whether non-cognitive risk factors improve predictive accuracy provided by cognitive factors alone.

METHODS

Multiple and logistic hierarchical regression analyses were utilized to predict different driving outcomes. In all regression models, we included cognitive predictors alone in a first step and added non-cognitive predictors in a second step.

RESULTS

Results revealed that the combination of cognitive and non-cognitive risk factors significantly predicted driving skills (R2adjusted = 0.30) and fitness to drive (81.2% accuracy) as well as the number (R2adjusted = 0.21) and occurrence (88.3% accuracy) of prospective minor at-fault accidents within the next 12 months. In all analyses, the inclusion of non-cognitive risk factors led to a significant increase of explained variance in the different outcome variables.

CONCLUSION

Our findings suggest that a combination of the most robust cognitive and non-cognitive risk factors may allow an economic and accurate prediction of on-road driving performance and prospective accident risk in healthy older drivers and drivers with MCI. Therefore, non-cognitive risk factors appear to play an important role.

Assessing fitness to drive in older adults: Validation and extension of an economical screening tool

OBJECTIVES

Due to demographic change, the number of older drivers with impaired driving skills will increase in the next decades. The current study aimed at the validation and extension of the screening tool Safety Advice For Elderly drivers (SAFE) that allows a cost-efficient assessment of driving-related risk factors in older drivers.

METHOD

Seventy-four older drivers aged ≥65 years (M = 77 years) recruited from the general population were included in this prospective observational study. Receiver operating characteristic curve (ROC) and hierarchical logistic regression analyses were utilized to examine whether the SAFE and further evidence-based driving-related factors may allow the differentiation between fit and unfit older drivers assessed in standardized on-road driving assessments.

RESULTS

ROC analyses revealed significant diagnostic accuracy of the number of SAFE risk factors in differentiating between fit and unfit older drivers (AUC = 0.71). A stepwise logistic regression model revealed that adding further evidence-based risk factors into the SAFE clearly improved diagnostic accuracy (AUC = 0.85).

DISCUSSION

The current study shows that the risk assessed by the SAFE predicts on-road driving fitness in older adults. However, the results also suggest a need for a modification of the SAFE by the inclusion of additional evidence-based risk factors. With sensitivity and specificity scores of about 90 % and 75 %, this modified version may be more suitable for clinical use.

Avoidance Behavior Is an Independent Indicator of Poorer On-road Driving Skills in Older Adults

OBJECTIVES

The aim of the current work was to investigate the relationship between avoidance of specific driving situations and on-road driving skills in older drivers considering factors found to be related to both avoidance behavior and driving skills.

METHOD

Seventy-two older drivers (M = 76 years) from the general population were included in this study. Self-reported avoidance behavior, driving practice, perceived driving difficulties, driving-related cognitive functions, as well as medical conditions were assessed within two sessions. Standardized on-road assessments served for assessing on-road driving skills in a third session.

RESULTS

Self-reported avoidance behavior was associated with reduced driving skills (r = -.41), and this relationship remained significant beyond the influence of cognitive skills, self-reported health, driving practice, and perceived driving difficulties. Specifically, avoidance of driving in bad weather, poor visibility and complicated parking was found to be associated with reduced driving skills.

DISCUSSION

This study suggest that avoidance behavior is an independent indicator of impaired driving skills in older drivers. Our results argue against the assumption that avoidance behavior may be a reasonable strategy for safe traffic participation. Longitudinal studies are urgently needed to get more evidence on safety aspects of avoidance behavior.

Nonacceptance of negative emotions in women with borderline personality disorder: association with neuroactivity of the dorsal striatum

BACKGROUND

Emotion dysfunction is a key symptom in patients with borderline personality disorder (BPD) and is considered a consequence of dysfunctional emotion regulation (e.g., reduced emotion acceptance). In the present functional MRI (fMRI) study, we investigated the neural correlates of habitual emotion acceptance in individuals with BPD.

METHODS

Female patients with BPD and female healthy controls passively viewed negative and neutral movie clips of faces during fMRI. We assessed emotion acceptance using the Emotion Acceptance Questionnaire (EAQ). To examine brain activation associated with habitual emotional acceptance of negative stimuli, the EAQ score was included as a regressor of interest in brain data analyses of activation intensity during negative compared with neutral movies.

RESULTS

We included 20 women with BPD and 20 heatlhy controls in our analysis. Compared with healthy controls, patients with BPD showed significantly more activation in frontostriatal brain regions (i.e., left superior frontal gyrus, right caudate) as well as in the left precuneus, left precentral gyrus, left posterior cingulate cortex and left hippocampus when confronted with negative (v. neutral) stimuli. Patients with BPD reported decreased emotion acceptance compared with healthy controls, and habitual emotion acceptance was inversely associated with activation of striatal areas (i.e., left putamen, left caudate) in patients with BPD.

LIMITATIONS

Causal conclusions are not possible. Comorbid diagnoses were not excluded, and only female participants were investigated. Stimuli were not rated immediately and may not be generalizable to all negative emotions. We cannot make any statements about other emotion-regulation strategies that may have been applied here.

CONCLUSION

Data indicate that striatal hyperactivation during the processing of negative stimuli in women with BPD is related to their decreased disposition to accept unpleasant emotional states. Thus, individuals with BPD may benefit from therapy approaches that focus on emotion acceptance in order to normalize emotional reactions.

Driving Fitness in Different Forms of Dementia: An Update

BACKGROUND/OBJECTIVES

Most forms of dementia are associated with progressive cognitive and noncognitive impairments that can severely affect fitness to drive. Whether safe driving is still possible in the single case, however, is often difficult to decide and may be dependent on both severity and type of the respective dementia syndrome. Particularly in early disease stages, Alzheimer disease dementia (ADD) and different types of non-Alzheimer dementias, such as vascular dementia (VaD), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), and Parkinson disease dementia (PDD), might differentially affect fitness to drive.

DESIGN

To examine the effects of severity and type of dementia on driving fitness, we conducted a systematic review with qualitative narrative synthesis, involving different driving outcomes in different forms and stages of dementia.

SETTING

Literature research included MEDLINE and PsycINFO databases with a focus on the most relevant and recent publications on the topic.

PARTICIPANTS

The population of interest included older drivers in different stages of ADD and different forms of non-Alzheimer dementias (VaD, FTD, DLB, and PDD).

MEASUREMENTS

Narrative description of driving outcomes in the population of interest.

RESULTS

Overall, previous studies suggest that driving fitness is severely impaired in moderate and severe dementia, irrespective of the type of dementia. In milder disease stages, fitness to drive appears to be more severely impaired in non-Alzheimer dementias than in ADD, since the non-Alzheimer syndromes are not only associated with driving-relevant cognitive but noncognitive risk factors, such as behavioral or motor symptoms.

CONCLUSIONS

Based on these findings, practical recommendations are presented, including a risk evaluation for driving safety, depending on severity and type of different dementia syndromes. J Am Geriatr Soc 67:2186-2192, 2019.

Performance Level and Cortical Atrophy Modulate the Neural Response to Increasing Working Memory Load in Younger and Older Adults

There is evidence that the neural response to increasing working memory (WM) load is modulated by age and performance level. For a valid interpretation of these effects, however, it is important to understand, whether and how they are related to gray matter atrophy. In the current work, we therefore used functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM) to examine the association between age, performance level, spatial WM load-related brain activation and gray matter volume in 18 younger high-performers (YHP), 17 younger low-performers (YLP), 17 older high-performers (OHP), and 18 older low-performers (OLP). In multiple sub regions of the prefrontal cortex (PFC), load-related activation followed a linear trend with increasing activation at increasing load in all experimental groups. Results did not reveal differences between the sub groups. Older adults additionally showed a pattern of increasing activation from low to medium load but stable or even decreasing activation from medium to high load in other sub regions of the PFC (quadratic trend). Quadratic trend related brain activation was higher in older than in younger adults and in OLP compared to OHP. In OLP, quadratic trend related brain activation was negatively correlated with both performance accuracy and prefrontal gray matter volume. The results suggest an efficient upregulation of multiple PFC areas as response to increasing WM load in younger and older adults. Older adults and particularly OLP additionally show dysfunctional response patterns (i.e., enhanced quadratic trend related brain activation compared to younger adults and OHP, respectively) in other PFC clusters being associated with gray matter atrophy.

Dissociating Normal Aging from Alzheimer's Disease: A View from Cognitive Neuroscience

Both normal aging and Alzheimer's disease (AD) are associated with changes in cognition, grey and white matter volume, white matter integrity, neural activation, functional connectivity, and neurotransmission. Obviously, all of these changes are more pronounced in AD and proceed faster providing the basis for an AD diagnosis. Since these differences are quantitative, however, it was hypothesized that AD might simply reflect an accelerated aging process. The present article highlights the different neurocognitive changes associated with normal aging and AD and shows that, next to quantitative differences, there are multiple qualitative differences as well. These differences comprise different neurocognitive dissociations as different cognitive deficit profiles, different weights of grey and white matter atrophy, and different gradients of structural decline. These qualitative differences clearly indicate that AD cannot be simply described as accelerated aging process but on the contrary represents a solid entity.

Advice for Elderly Drivers in a German Memory Clinic: A Case Report on Medical, Ethical and Legal Consequences

We report on a 75-year-old female who consulted our Memory Clinic because of subjective memory complaints that she first recognized three months previously. Next to the standard detailed patient history, neuropsychological assessment, psychopathological status, the patient's driving history played an important role in the diagnostic process. In this case report, we illustrate the diagnostic process starting with the first consultation, including a short neuropsychological examination and communicating its results, reporting on further work-up (detailed neuropsychological assessment, MRI scan and cerebrospinal fluid (CSF) analysis) up to the final consultation, including advice for the patient. We will focus on several medical, ethical and legal difficulties that may occur when consulting elderly drivers with initial cognitive decline.

Linking CSF and cognition in Alzheimer's disease: Reanalysis of clinical data

OBJECTIVES

Memory and executive deficits are important cognitive markers of Alzheimer's disease (AD). Moreover, in the past decade, cerebrospinal fluid (CSF) biomarkers have been increasingly utilized in clinical practice. Both cognitive and CSF markers can be used to differentiate between AD patients and healthy seniors with high diagnostic accuracy. However, the extent to which performance on specific mnemonic or executive tasks enables reliable estimations of the concentrations of different CSF markers and their ratios remains unclear.

METHODS

To address the above issues, we examined the association between neuropsychological data and CSF biomarkers in 51 AD patients using hierarchical multiple regression analyses. In the first step of these analyses, age, education and sex were entered as predictors to control for possible confounding effects. In the second step, data from a neuropsychological test battery assessing episodic memory, semantic memory and executive functioning were included to determine whether these variables significantly increased (compared to step 1) the explained variance in Aβ42 concentration, p-tau concentration, t-tau concentration, Aβ42/t-tau ratio, and Aβ42/Aβ40 ratio.

RESULTS

The different models explained 52% of the variance in Aβ42/t-tau ratio, 27% of the variance in Aβ42 concentration, and 28% of the variance in t-tau concentration. In particular, Aβ42/t-tau ratio was associated with verbal recognition and code shifting, with Aβ42 being related to verbal recognition and t-tau being related to code shifting. By contrast, the inclusion of neuropsychological data did not allow reliable estimations of Aβ42/Aβ40 ratio or p-tau concentration.

CONCLUSION

Our results showed that strong associations exist between the cognitive key symptoms of AD and the concentrations and ratios of specific CSF markers. In addition, we revealed a specific combination of neuropsychological tests that may facilitate reliable estimations of CSF concentrations, thereby providing important diagnostic information for non-invasive early AD detection.

The significance of caudate volume for age-related associative memory decline

Aging comes along with reduced gray matter (GM) volume in several cerebral areas and with cognitive performance decline in different cognitive domains. Moreover, regional GM volume is linked to specific cognitive sub processes in older adults. However, it remains unclear which regional changes in older individuals are directly associated with decreased cognitive performance. Moreover, most of the studies on this topic focused on hippocampal and prefrontal brain regions and their relation to memory and executive functioning. Interestingly, there are only a few studies that reported an association between striatal brain volume and cognitive performance. This is insofar surprising that striatal structures are (1) highly affected by age and (2) involved in different neural circuits that serve intact cognition. To address these issues, voxel-based morphometry (VBM) was used to analyze GM volume in 18 younger and 18 older adults. Moreover, several neuropsychological tests from different neuropsychological test batteries were applied to assess a broad range of cognitive domains. Older adults showed less GM volume than younger adults within frontal, striatal, and cerebellar brain regions. In the group of older adults, significant correlations were found between striatal GM volume and memory performance and between prefrontal/temporal GM volume and executive functioning. The only direct overlap between brain regions associated with regional atrophy and cognitive performance in older adults was found for the right caudate: older adults showed reduced caudate volume relative to younger adults. Moreover, caudate volume was positively correlated with associative memory accuracy in older adults and older adults showed poorer performances than younger adults in the respective associative memory task. Taken together, the current findings indicate the relevance of the caudate for associative memory decline in the aging brain.

The impact of age on load-related dorsolateral prefrontal cortex activation

Healthy aging is accompanied by working memory-related functional cerebral changes. Depending on performance accuracy and the level of working memory demands, older adults show task-related patterns of either increased or decreased activation compared to younger adults. Controversies remain concerning the interpretation of these changes and whether they already manifest in earlier decades of life. To address these issues, functional magnetic resonance imaging (fMRI) was used to examine brain activation during spatial working memory retrieval in 45 healthy individuals between 20 and 68 years of age. Participants performed a modified version of the Corsi Block-Tapping test (CBT). The CBT requires the storage and subsequent reproduction of spatial target sequences and allows modulating working memory load by a variation of sequence length. Results revealed that activation intensity at the lowest CBT load level increased with increasing age and positively correlated with the number of errors. At higher CBT load levels, activation intensity decreased with increasing age together with a disproportional accuracy decline on the behavioral level. Moreover, results suggests that younger individuals showed higher activation intensity at high CBT load than at low CBT load switching to the opposite pattern at an age of about 40 years. Consistent with the assumptions of the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), the present results reveal specific age-related alterations in left dorsolateral prefrontal cortex activation in response to increasing task load. Specifically, the results point toward increasing neural inefficiency with age at low task load and a progressive limitation of resources with age at higher task load. The present findings argue for an increasing functional cerebral dysfunction over a time span of 50 years that may partly be compensated on the behavioral level until a resource ceiling is approached.

Integrated wireless neural interface based on the Utah electrode array

This report presents results from research towards a fully integrated, wireless neural interface consisting of a 100-channel microelectrode array, a custom-designed signal processing and telemetry IC, an inductive power receiving coil, and SMD capacitors. An integration concept for such a device was developed, and the materials and methods used to implement this concept were investigated. We developed a multi-level hybrid assembly process that used the Utah Electrode Array (UEA) as a circuit board. The signal processing IC was flip-chip bonded to the UEA using Au/Sn reflow soldering, and included amplifiers for up to 100 channels, signal processing units, an RF transmitter, and a power receiving and clock recovery module. An under bump metallization (UBM) using potentially biocompatible materials was developed and optimized, which consisted of a sputter deposited Ti/Pt/Au thin film stack with layer thicknesses of 50/150/150 nm, respectively. After flip-chip bonding, an underfiller was applied between the IC and the UEA to improve mechanical stability and prevent fluid ingress in in vivo conditions. A planar power receiving coil fabricated by patterning electroplated gold films on polyimide substrates was connected to the IC by using a custom metallized ceramic spacer and SnCu reflow soldering. The SnCu soldering was also used to assemble SMD capacitors on the UEA. The mechanical properties and stability of the optimized interconnections between the UEA and the IC and SMD components were measured. Measurements included the tape tests to evaluate UBM adhesion, shear testing between the Au/Sn solder bumps and the substrate, and accelerated lifetime testing of the long-term stability for the underfiller material coated with a a-SiC(x):H by PECVD, which was intended as a device encapsulation layer. The materials and processes used to generate the integrated neural interface device were found to yield a robust and reliable integrated package.

Neural correlates of the individual emotional Stroop in borderline personality disorder

OBJECTIVE

Emotional dysregulation is a key feature of borderline personality disorder (BPD) with altered inhibitory functions having suggested as being crucial. The anterior cingulate cortex and further prefrontal brain regions are crucial for response inhibition. The regulation of emotions is ensured via inhibitory control over the amygdala. The present study aimed to investigate neural correlates of response inhibition in BPD by using an emotional Stroop paradigm extending the task to word stimuli which were related to stressful life events.

METHODS

Twenty BPD patients and 20 healthy controls underwent functional magnetic resonance imaging (fMRI) while performing the individual emotional Stroop task. A block design was used with the following word type conditions: neutral words, general negative words, and individual negative words. The individual negative words were recruited from a prior interview conducted with each participant.

RESULTS

While BPD patients had overall slower reaction times in the Stroop task compared to healthy controls, there was no increased slowing with emotional interference. Controls exhibited significant fMRI blood oxygenation level-dependent signal increases in the anterior cingulate cortex as well as in frontal cortex contrasting generally negative vs. neutral and individual negative vs. neutral conditions, respectively. BPD patients did not show equivalent signal changes.

CONCLUSIONS

These results provide further evidence for a dysfunctional network of brain areas in BPD, including the ACC and frontal brain regions. These areas are crucial for the regulation of stress and emotions, the core problems of BPD patients.

Early detection of Alzheimer's disease: a new working memory paradigm

OBJECTIVES

Early detection of Alzheimer's disease (AD) offers the chance to decelerate the patients' cognitive decline and to prolong a self-determined, independent life. Neuropsychological testing is one key approach to establish an early diagnosis. Whereas more global cognitive abilities can be preserved until further progression of the disease, specific executive abilities such as dual-task or active inhibition processes decline very early. Our recently developed working memory paradigm, the Block Suppression Test (BST), requires an active inhibition of irrelevant stimuli and thus should differentiate between Alzheimer patients and controls in early disease stages more accurately than classical screening instruments.

METHODS

In a pilot study we applied the BST, the MMSE, the clock drawing test, a digit-word transformation task as well as verbal and spatial memory span tasks to a group of 13 patients with Alzheimer's disease and 13 elderly controls and compared the instruments' capability to differentiate between patients and controls.

RESULTS

The BST showed the highest sensitivity among all applied tests with a perfect differentiation of healthy subjects and patients. The patients' backward spans were significantly reduced, in the inhibition condition they showed disproportionally worse performances.

CONCLUSIONS

Our results reveal a specific inhibition deficit in mild AD rather than a global working memory breakdown. The BST thus was superior for early diagnosis. However, these findings must be replicated in a larger sample to prove the BST's applicability for the early diagnostic assessment of AD and other dementias.

Switchable Polymer Based Thin Film Coils as a Power Module for Wireless Neural Interfaces

Reliable chronic operation of implantable medical devices such as the Utah Electrode Array (UEA) for neural interface requires elimination of transcutaneous wire connections for signal processing, powering and communication of the device. A wireless power source that allows integration with the UEA is therefore necessary. While (rechargeable) micro batteries as well as biological micro fuel cells are yet far from meeting the power density and lifetime requirements of an implantable neural interface device, inductive coupling between two coils is a promising approach to power such a device with highly restricted dimensions. The power receiving coils presented in this paper were designed to maximize the inductance and quality factor of the coils and microfabricated using polymer based thin film technologies. A flexible configuration of stacked thin film coils allows parallel and serial switching, thereby allowing to tune the coil's resonance frequency. The electrical properties of the fabricated coils were characterized and their power transmission performance was investigated in laboratory condition.