Visual p300 effects beyond symptoms in concussed college athletes

In order to assess whether cerebral anomalies may be observed in the absence of clinical symptoms, the current study compared the effects of concussions on attentional capacities (reaction times, accuracy) and Event-Related Potentials (ERPs) in concussed athletes with (n = 10) or without (n = 10) symptoms as well as in athletes who never had a concussion (n = 10). The P300 response was recorded from 28 electrodes during a modified visual oddball paradigm. Participants were instructed to press a key upon the appearance of the frequent stimuli as well as when a rare nontarget stimulus followed the frequent one. The other key was to be pressed when the subsequent rare stimuli (rare target) appeared until a frequent one reappeared. The symptomatic athletes displayed longer reaction times than the other two groups of athletes. The P300 amplitude to the rare target stimuli was significantly more attenuated in the symptomatic athletes than in the other two groups. Moreover, the P300 amplitude varied inversely with the severity of post-concussion symptoms but was not influenced by time elapsed since injury. Although the clinical significance of the P300 differences shown by the symptomatic athletes is still uncertain, the results do indicate that symptom severity may be a crucial indicator of functional impairments following mild traumatic brain injury.     

Reduced brain glutamine in female varsity rugby athletes after concussion and in non‐concussed athletes after a season of play

The purpose of this study was to use non‐invasive proton magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) to monitor changes in prefrontal white matter metabolite levels and tissue microstructure in female rugby players with and without concussion (ages 18–23, n = 64). Evaluations including clinical tests and 3 T MRI were performed at the beginning of a season (in‐season) and followed up at the end of the season (off‐season). Concussed athletes were additionally evaluated 24–72 hr (n = 14), three months (n = 11), and six months (n = 8) post‐concussion. Reduced glutamine at 24–72 hr and three months post‐concussion, and reduced glutamine/creatine at three months post‐concussion were observed. In non‐concussed athletes (n = 46) both glutamine and glutamine/creatine were lower in the off‐season compared to in‐season. Within the MRS voxel, an increase in fractional anisotropy (FA) and decrease in radial diffusivity (RD) were also observed in the non‐concussed athletes, and correlated with changes in glutamine and glutamine/creatine. Decreases in glutamine and glutamine/creatine suggest reduced oxidative metabolism. Changes in FA and RD may indicate neuroinflammation or re‐myelination. The observed changes did not correlate with clinical test scores suggesting these imaging metrics may be more sensitive to brain injury and could aid in assessing recovery of brain injury from concussion.     

The relation between neurocognitive dysfunction and impaired insight in patients with schizophrenia

ObjectivesThe present study aimed to (i) evaluate the association between insight and measures of executive functions and working memory in a sample of 132 patients with schizophrenia and (ii) to explore to what proportion neurocognitive dysfunction contributed to the variance in insight after controlling for symptomatology.MethodsSubjects were evaluated with a standardized neurocognitive test battery and a semi-structured interview, the Psychosis Evaluation tool for Common use by Caregivers (PECC). PECC, apart from evaluating symptoms and side-effects, measures insight on a 4-point scale by two of its dimensions: awareness of having a mental illness (AMI) and awareness of having symptoms attributed to a mental illness (ASAMI). Executive functioning was measured by the Wisconsin Card Sort Test (WCST) and the Trail Making B (TMB). Working memory was measured by the Letter Number Sequencing (LNS) test from the Wechsler Adult Intelligence Scale (WAIS).ResultsOnly one significant association was found after correction for multiple testing, between WCST categories completed and AMI (r = ?0.29, p = 0.0006). WCST categories completed explained only 7.9% of the variance in AMI, while symptomatology explained 20% of variance in AMI and 16.5% of variance in ASAMI.ConclusionsThe current results show a significant but subtle association with the WCST, which is in agreement with earlier literature. No other associations between cognitive functioning and insight were found. In general, these findings seem to suggest that factors other than cognition have a greater impact on insight in patients with schizophrenia.     

Cumulative concussion exposure in rugby players: neurocognitive and symptomatic outcomes

A total of 111 rugby players underwent comprehensive testing to determine the impact of self-reported concussion exposure. Reliable estimates of concussion exposure were associated with an increase in postconcussion symptoms (PCS), but not diminished neurocognitive functioning. Importantly, the effects of concussion exposure on PCS varied as a function of player status. More specifically, extent of concussion exposure was associated with increased memory complaints and overall PCS endorsements in a dose-dependent manner for retired and older recreational players, but not for those who were younger and playing at more competitive levels. Future work should systematically evaluate the constituent participant factors that may influence differential concussion outcomes.     

Dimensionality and neurocognitive symptoms in OCD

Obsessive-compulsive disorder (OCD) is composed of heterogenous phenomenological symptoms. The genetic background is proved but not described in detail; thus it seems to advantageous clustering the symptoms into groups, also called dimensions. The 71 items of the Y-BOCS symptom list have been subdivided in several ways. A subdivision system of 5 different factors in OCD has been proposed recently for the DSM-V instead of the 3 factor model of the DSM-IV used today (I. predominantly obsessive/ II. predominantly compulsive/ III. mixed subgroup). These factors as endophenotypes are supposed to be transmitted by common genetical pathways. Subdivision of the OCD by factors helps us to reveal the relation between subgroups of gender, age of onset of the disease, comorbid illnesses, and the responsivity to treatment. This approach of dimensionality is also useful in understanding the neurocognitive differences experienced in OCD. This is why we summarised up-to-date findings of the neurocognitive deficits connected to the affected brain areas in OCD: OFC, DLPFC, ACC, striatum, amygdala, thalamus. Finally the cognitive domains affected in OCD are summarised, such as: memory, planning, decision making, response inhibition, set-shifting, and attention deficits.     

Cerebrospinal fluid kynurenines in multiple sclerosis; relation to disease course and neurocognitive symptoms

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system, with a high rate of neurocognitive symptoms for which the molecular background is still uncertain. There is accumulating evidence for dysregulation of the kynurenine pathway (KP) in different psychiatric and neurodegenerative conditions. We here report the first comprehensive analysis of cerebrospinal fluid (CSF) kynurenine metabolites in MS patients of different disease stages and in relation to neurocognitive symptoms.Levels of tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QUIN) were determined with liquid chromatography mass spectrometry in cell-free CSF. At the group level MS patients (cohort 1; n = 71) did not differ in absolute levels of TRP, KYN, KYNA or QUIN as compared to non-inflammatory neurological disease controls (n = 20). Stratification of patients into different disease courses revealed that both absolute QUIN levels and the QUIN/KYN ratio were increased in relapsing-remitting MS (RRMS) patients in relapse. Interestingly, secondary progressive MS (SPMS) displayed a trend for lower TRP and KYNA, while primary progressive (PPMS) patients displayed increased levels of all metabolites, similar to a group of inflammatory neurological disease controls (n = 13). In the second cohort (n = 48), MS patients with active disease and short disease duration were prospectively evaluated for neuropsychiatric symptoms. In a supervised multivariate analysis using orthogonal projection to latent structures (OPLS-DA) depressed patients displayed higher KYNA/TRP and KYN/TRP ratios, mainly due to low TRP levels. Still, this model had low predictive value and could not completely separate the clinically depressed patients from the non-depressed MS patients. No correlation was evident for other neurocognitive measures. Taken together these results demonstrate that clinical disease activity and differences in disease courses are reflected by changes in KP metabolites. Increased QUIN levels of RRMS patients in relapse and generally decreased levels of TRP in SPMS may relate to neurotoxicity and failure of remyelination, respectively. In contrast, PPMS patients displayed a more divergent pattern more resembling inflammatory conditions such as systemic lupus erythematosus. The pattern of KP metabolites in RRMS patients could not predict neurocognitive symptoms.     

Self-reported attention and mood symptoms in cocaine abusers: Relationship to neurocognitive performance

Objective: This study examined the relationship between subjective measures of inattention/hyperactivity−impulsivity and mood and objective measures of neurocognitive function in cocaine users. Design: Ninety-four active cocaine users not seeking treatment (73 male, 21 female) were administered two self-report psychiatric measures (the ADHD Rating Scale – Fourth Edition; ARS-IV), and the Beck Depression Inventory – Second Edition; (BDI-II), and a battery of tests measuring attention, executive, psychomotor, visual and verbal learning, visuospatial, and language functions. Correlations between scores on the psychiatric measures (total and subscale) and the neurocognitive measures were examined. Results: While scores on the BDI-II and ARS-IV were correlated with each other (p<0.01), scores on both self-report measures were largely uncorrelated with neurocognitive test scores (p>0.05). Conclusion: There was a minimal relationship between psychiatric measures that incorporate subjective assessment of cognitive function, and objective neurocognitive measures in nontreatment-seeking cocaine users, consistent with previous findings in other samples of substance users. This suggests that self-report measures may have limited utility as proxies for neurocognitive performance.     

Association of clinical symptoms and neurocognitive performance in bipolar disorder: a longitudinal study

Chaves OC, Lombardo LE, Bearden CE, Woolsey MD, Martinez DM, Barrett JA, Miller AL, Velligan DI, Glahn DC. Association of clinical symptoms and neurocognitive performance in bipolar disorder: a longitudinal study.
Bipolar Disord 2011: 13: 118–123. © 2011 The Authors. Journal compilation © 2011 John Wiley & Sons A/S. Objective: Despite evidence that individuals with bipolar disorder have neurocognitive impairment that persists during euthymia, the impact of changes in affective symptoms on cognitive function has not been well established. Here, we sought to determine whether specific neurocognitive functions are sensitive to mood changes in individuals with bipolar disorder assessed three months apart without changes in treatment regimen. Methods: A total of 29 individuals with DSM‐IV bipolar disorder and 30 healthy controls participated in the study. All participants received a comprehensive neuropsychological assessment and ratings of depressive [Hamilton Depression Rating Scale (HAMD)] and manic [Young Mania Rating Scale (YMRS)] symptoms at baseline and follow‐up. Changes in symptoms over time were calculated and were examined in relation to changes in neurocognitive performance. Results: At baseline, clinically stable but symptomatic patients were impaired on measures of speed of processing and attention. Over the three‐month follow‐up period, HAMD scores changed by 6 points on average [range: ?10 to +18] and YMRS scores changed by 5.31 points on average [range ?11 to +15]. Changes in depressive symptoms were correlated with poorer verbal fluency, while no relationship between manic symptoms and neuropsychological performance was detected. Conclusions: Individuals with bipolar disorder showed consistent impairment on speed of processing and attention over time, despite significant changes in mood.     

Combining MRI and cognitive evaluation to classify concussion in university athletes

Brain Imaging and Behavior - Current methods of concussion assessment lack the objectivity and reliability to detect neurological injury. This multi-site study uses combinations of neuroimaging...     

Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion.

Neuropsychology, with its emphasis on standardized and empirically based methods, has made a number of scientific contributions to address growing concerns about concussions resulting from sports injuries. This study employs a test-retest paradigm to determine the immediate effects of concussion in high-school and college athletes. The Standardized Assessment of Concussion (SAC) was administered to 1,313 male athletes prior to the beginning of the competitive season. Reliable change indices and multiple regression models were computed on retest scores obtained from 68 noninjured athletes who were readministered the SAC at either 60 or 120 days following baseline testing. Receiver operating characteristic (ROC) curve analyses were used to test these models with data obtained on 50 athletes tested immediately following concussion. The results indicate that a decline of I point on the SAC at retesting classified injured and noninjured participants with a level of 94% sensitivity and 76% specificity. The RCI and multiple regression models provided comparable levels of group classification, but provided cut-offs that are conservative for use with this population. The results support and extend previous research findings indicating that the SAC is a valid instrument for detecting the immediate effects of mild traumatic brain injury.     

Association between Dementia Rating Scale performance and neurocognitive domains in Alzheimer''s disease

The Dementia Rating Scale (DRS; Mattis, 1976, 1988) is commonly used in the assessment of dementia, although little is known about the relationship of performance on this test to specific cognitive deficits in Alzheimer's disease (AD). Additionally, cognitive profiles have not been investigated across different levels of dementia as determined by the DRS. A sample of 133 individuals diagnosed with possible or probable AD was administered the DRS as part of a comprehensive neuropsychological evaluation. Composite scores for the cognitive domains of attention, executive functioning, visuospatial skills, language abilities, immediate recall, and delayed memory were derived by averaging demographically corrected T scores of key measures. Individual domain scores were also averaged to develop a global index score. Pearson correlations between composite and total DRS scores were highly significant (p<.001) for all domains and the global index score, with the exception of delayed memory, which showed a floor effect. When the sample was divided into mild and moderate-to-severe groups to examine the effects of disease severity on the relationship between the DRS and standard neurocognitive domain scores, the resulting mean neuropsychological profile scores were significantly different while maintaining a parallel pattern of impairment across domains. Results demonstrate the relationship between the DRS and standard cognitive domain functions, which appears to underscore the validity and robustness of the DRS in characterizing patterns of cognitive impairment across the AD spectrum.     

卒中后抑郁与急性期神经功能缺损程度的相关研究

目的 探讨脑卒中后抑郁（post stroke depression,PSD）发生率以及与急性期神经功能缺损程度的关系。方法 对289例住院诊断为脑卒中的患者,用改良的爱丁堡斯堪的那维亚神经功能缺损评分表（SSS）对卒中急性期进行评分,根据急性期神经功能缺损情况分为三组。用汉密尔顿抑郁量表进行随访调查抑郁评分。结果 PSD的发病率在随访1年期间中随着时间的延长逐渐增加;PSD的发病率和重度PSD的发病率随神经功能缺损程度的加重而增加;PSD的程度随着神经功能缺损程度增加而加重。结论 PSD是脑卒中后的常见并发症,卒中后1年中发病率逐渐增加,其严重程度与卒中急性期的神经功能缺损程度一致。     

Last night's sleep in relation to academic achievement and neurocognitive testing performance in adolescents with and without ADHD

Objectives/backgroundObjectives were to (1) examine previous night's sleep in relation to next day performance on standardized academic achievement and neurocognitive assessments in adolescents, and (2) explore whether previous night's sleep is differentially associated with testing performance for adolescents with and without attention-deficit/hyperactivity disorder (ADHD).Participants/methodsParticipants were 300 adolescents (ages 12–14 years; 55% male). Approximately half (53.6%) were diagnosed with ADHD. Adolescents provided ratings of their previous night's sleep quality, sleep duration, and number of night wakings and were administered standardized tests of processing speed and working memory, as well as word reading, numerical operations, and math fluency academic achievement.ResultsIn analyses controlling for sex, race, medication use, time of testing, and ADHD group status, more night wakings the previous night were associated with significantly lower numerical operations and math fluency achievement scores and marginally lower working memory scores. Previous night's sleep was not associated with processing speed or reading achievement. ADHD status did not moderate sleep in relation to academic/neurocognitive performance. Participants reporting ≥2 night wakings the previous night had slightly over half a standard deviation lower scores on average compared to participants reporting 0 night wakings.ConclusionsThis preliminary study suggests that previous night's wakings are associated with poorer mathematics performance the next day, regardless of ADHD status. This may be due to the detrimental effect of interrupted and fragmented sleep on attention and executive control. These findings have implications for clinicians and educators when considering contextual factors that may impact academic and neurocognitive testing performance.     

A validation of the post concussion symptom scale in the assessment of complex concussion using cognitive testing and functional MRI

Background

Clinical assessment of cerebral concussion relies on the presence and duration of post concussive symptoms (PCS). Given that these PCS are subjective reports and not always specific to concussion, their usefulness remains to be validated.

Objective

To evaluate the usefulness of self‐reported PCS by means of cognitive tests and functional MRI (fMRI).

Method

28 male athletes with and without concussion were grouped according to their PCS score. They were then administered a computerised cognitive test battery and submitted to an fMRI session where cerebral activations associated with verbal and non‐verbal working memory tasks were analysed.

Results

Behaviourally, response accuracy and speed on the cognitive test battery were comparable for the control and low PCS group. The moderate PCS group showed significantly slower response times than the control group on the matching (p<0.05) and one‐back tasks (p<0.05). The functional MRI study showed reduced task related activation patterns in the dorsolateral prefrontal cortex for both low and moderate PCS groups. Activation peaks outside the regions of interest, not seen in the control group, were also noted for both PCS groups. Regression analyses indicated an inverse relationship between PCS scores and performances on several CogSport subtests. Severity of PCS also predicted fMRI blood oxygen level dependent signal changes in cerebral prefrontal regions.

Conclusion

Self‐reported PCS is associated with an ongoing cerebral haemodynamic abnormality as well as with mild cognitive impairment. These results support the use of the PCS scale in the assessment of cerebral concussion and in monitoring recovery.Cerebral concussion is a common injury seen in contact and collision sport. The frequency of self‐reported concussion is particularly high in ice hockey, American football and soccer, where up to 50% of players report a history of at least one concussion.^1,2,3 It is likely that these values represent an underestimate of the actual incidence of concussion as many players either fail to recognise that they experienced such an injury or are reluctant to report the injury because of fear of exclusion from match play.^4,5,6,7Physicians involved in the care of concussed athletes frequently face the dilemma of when to allow a player to return to play. The challenge in making such a decision stems from the fact that sport related concussion does not produce a detectable structural lesion and few scientifically validated diagnostic instruments exist to help identify concussive brain injury and to determine concussion recovery.⁸ In the past, post concussion management has centred on the application of return to play guidelines which utilise an arbitrary period of mandatory exclusion following injury. As none of the published guidelines have been prospectively validated, it was recommended by the Vienna Conference on Concussion in Sport that they be abandoned in favour of an individualised assessment of recovery.⁹ A key element in determining clinical recovery from concussion is the presence of post concussive symptoms (PCS). Consequently, concussion symptom checklists have been added to several management guidelines.The usefulness of PCS in the assessment of cerebral concussion remains unclear given that such symptoms are non‐specific in nature and a large percentage of the normal population report identical symptoms in the absence of a history of concussive injury.^10,11,12,13 This is especially problematic in athletes with persisting symptoms, as little is known about the nature of PCS in this particular population. Validation of self‐rated PCS scales in cases of chronic PCS can be achieved by correlating its measure with other objective assessments, such as those provided by neuropsychological tests. In addition to cognitive measures, novel functional imaging techniques such as functional MRI (fMRI) may provide an objective evaluation of concussive injury. Although the use of fMRI in concussion research is still in its infancy, initial studies have suggested promising results.^14,15The present study was designed to define the relationship between self‐reported PCS, neuropsychological performance and fMRI activation studies in a group of concussed athletes with persisting PCS who had suffered a complex concussion, as defined by the Prague Conference on Concussion in Sport.¹⁶ A concussion is considered “complex” when one or more of the following criteria are met: (1) specific sequelae, such as concussive convulsions; (2) loss of consciousness of more than 1 min; (3) persistent symptoms or prolonged cognitive impairment after the injury; and (4) history of multiple concussions over time. Our primary objective was to evaluate the use of a PCS score as a diagnostic indicator in complex concussion, and to investigate whether the severity of self‐rated symptoms reflects the degree of ongoing behavioural and functional changes after a cerebral concussion.