Gluten-induced cognitive impairment ("brain fog") in coeliac disease.

Much is known about the serious neurological effects of gluten ingestion in coeliac disease patients, such as sporadic ataxia and peripheral neuropathy, although the causal links to gluten are still under debate. However, such disorders are observed in only a small percentage of coeliac patients. Much less is known about the transient cognitive impairments to memory, attention, executive function, and the speed of cognitive processing reported by the majority of patients with coeliac disease. These mild degradations of cognitive functions, referred to as "brain fog," are yet to be formally recognized as a medical or psychological condition. However, subtle tests of cognitive function are measurable in untreated patients with coeliac disease and improve over the first 12 months' therapy with a gluten-free diet. Such deficits also occur in patients with Crohn's disease, particularly in association with systemic inflammatory activity. Thus, cognitive impairments associated with brain fog are psychologically and neurologically real and improve with adherence to a gluten-free diet. There is not yet sufficient evidence to provide a definitive account of the mechanism by which gluten ingestion causes the impairments to cognitive function associated with brain fog, but current evidence suggests that it is more likely that the causal factor is not directly related to exposure to gluten.

Characterising receptive language processing in schizophrenia using word and sentence tasks.

INTRODUCTION: Language dysfunction is proposed to relate to the speech disturbances in schizophrenia, which are more commonly referred to as formal thought disorder (FTD). Presently, language production deficits in schizophrenia are better characterised than language comprehension difficulties. This study thus aimed to examine three aspects of language comprehension in schizophrenia: (1) the role of lexical processing, (2) meaning attribution for words and sentences, and (3) the relationship between comprehension and production. METHODS: Fifty-seven schizophrenia/schizoaffective disorder patients and 48 healthy controls completed a clinical assessment and three language tasks assessing word recognition, synonym identification, and sentence comprehension. Poorer patient performance was expected on the latter two tasks. RESULTS: Recognition of word form was not impaired in schizophrenia, indicating intact lexical processing. Whereas single-word synonym identification was not significantly impaired, there was a tendency to attribute word meanings based on phonological similarity with increasing FTD severity. Importantly, there was a significant sentence comprehension deficit for processing deep structure, which correlated with FTD severity. CONCLUSIONS: These findings established a receptive language deficit in schizophrenia at the syntactic level. There was also evidence for a relationship between some aspects of language comprehension and speech production/FTD. Apart from indicating language as another mechanism in FTD aetiology, the data also suggest that remediating language comprehension problems may be an avenue to pursue in alleviating FTD symptomatology.

Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows' milk.

BACKGROUND: Cows' milk generally contains two types of ß-casein, A1 and A2 types. Digestion of A1 type can yield the peptide ß-casomorphin-7, which is implicated in adverse gastrointestinal effects of milk consumption, some of which resemble those in lactose intolerance. This study aimed to compare the effects of milk containing A1 ß-casein with those of milk containing only A2 ß-casein on inflammation, symptoms of post-dairy digestive discomfort (PD3), and cognitive processing in subjects with self-reported lactose intolerance. METHODS: Forty-five Han Chinese subjects participated in this double-blind, randomized, 2 × 2 crossover trial and consumed milk containing both ß-casein types or milk containing only A2 ß-casein. Each treatment period was 14 days with a 14-day washout period at baseline and between treatment periods. Outcomes included PD3, gastrointestinal function (measured by smart pill), Subtle Cognitive Impairment Test (SCIT), serum/fecal laboratory biomarkers, and adverse events. RESULTS: Compared with milk containing only A2 ß-casein, the consumption of milk containing both ß-casein types was associated with significantly greater PD3 symptoms; higher concentrations of inflammation-related biomarkers and ß-casomorphin-7; longer gastrointestinal transit times and lower levels of short-chain fatty acids; and increased response time and error rate on the SCIT. Consumption of milk containing both ß-casein types was associated with worsening of PD3 symptoms relative to baseline in lactose tolerant and lactose intolerant subjects. Consumption of milk containing only A2 ß-casein did not aggravate PD3 symptoms relative to baseline (i.e., after washout of dairy products) in lactose tolerant and intolerant subjects. CONCLUSIONS: Consumption of milk containing A1 ß-casein was associated with increased gastrointestinal inflammation, worsening of PD3 symptoms, delayed transit, and decreased cognitive processing speed and accuracy. Because elimination of A1 ß-casein attenuated these effects, some symptoms of lactose intolerance may stem from inflammation it triggers, and can be avoided by consuming milk containing only the A2 type of beta casein. TRIAL REGISTRATION: ClinicalTrials.gov/NCT02406469.

Validity of a screening tool for detecting subtle cognitive impairment in the middle-aged and elderly.

The present study tested 121 middle-aged and elderly community-dwelling individuals on the computer-based Subtle Cognitive Impairment Test (SCIT) and compared their performance with that on several neuropsychological tests. The SCIT had excellent internal consistency, as demonstrated by a high split-half reliability measure (0.88-0.93). Performance on the SCIT was unaffected by the confounding factors of sex, education level, and mood state. Many participants demonstrated impaired performance on one or more of the neuropsychological tests (Controlled Oral Word Association Task, Rey Auditory and Verbal Learning Task, Grooved Pegboard [GP], Complex Figures). Performance on SCIT subtests correlated significantly with performance on many of the neuropsychological subtests, and the best and worst performing quartiles on the SCIT subtest discriminated between good and poor performers on other subtests, collectively indicating concurrent validity of the SCIT. Principal components analysis indicated that SCIT performance does not cluster with performance on most of the other cognitive tests, and instead is associated with decision-making efficacy, and processing speed and efficiency. Thus, the SCIT is responsive to the processes that underpin multiple cognitive domains, rather than being specific for a single domain. Since the SCIT is quick and easy to administer, and is well tolerated by the elderly, it may have utility as a screening tool for detecting cognitive impairment in middle-aged and elderly populations.

Efficacy of cognitive processes in young people with high-functioning autism spectrum disorder using a novel visual information-processing task.

Autism spectrum disorders (ASD) are characterised by a unique pattern of preserved abilities and deficits within and across cognitive domains. The Complex Information Processing Theory proposes this pattern reflects an altered capacity to respond to cognitive demands. This study compared how complexity induced by time constraints on processing affect cognitive function in individuals with ASD and typically-developing individuals. On a visual information-processing task, the Subtle Cognitive Impairment Test, both groups exhibited sensitivity to time-constraints. Further, 65 % of individuals with ASD demonstrated deficits in processing efficiency, possibly attributable to the effects of age and clinical comorbidities, like attention deficit hyperactivity disorder. These findings suggest that for some ASD individuals there are significant impairments in processing efficiency, which may have implications for education and interventions.

Effects on cognition of conventional and robotically assisted cardiac valve operation.

BACKGROUND: The effect of valve surgical procedures on cognition was investigated in patients undergoing conventional or robotically assisted techniques. The confounding factors of surgical procedure, mood state, preexisting cognitive impairment, and repeated experience with cognitive tests were controlled for. METHODS: Patients undergoing conventional valve procedures (n = 15), robotically assisted valve procedures (n = 15), and thoracic surgical procedures (n = 15), along with a nonsurgical control group (n = 15) were tested preoperatively, 1 week after operation, and 8 weeks after operation by use of a battery of cognitive tests and a mood state assessment. Surgical group data were normalized against data from the nonsurgical control group before statistical analysis. RESULTS: Patients undergoing conventional valve procedures performed worse than those undergoing robotically assisted valve procedures on every subtest before operation, and this disadvantage persisted after operation. Age and premorbid intelligence quotient were significantly associated with performance on several cognitive subtests. Anxiety, depression, and stress were not associated with impaired cognitive performance in the surgical groups after operation. A week after operation, patients undergoing conventional valve procedures performed worse on the cognitive tests that had a motor component, which may reflect discomfort caused by the sternotomy. Patients undergoing robotically assisted valve procedures were significantly less impaired on information processing tasks 1 week after operation when compared with those undergoing conventional valve procedures. The majority of patients who were impaired 1 week after operation recovered to preoperation levels within 8 weeks. CONCLUSIONS: The robotically assisted valve surgical procedure results in more rapid recovery of performance on cognitive tests. However, regardless of the type of surgical intervention, the prospect of a recovery of cognitive performance to preoperative levels is high.

Recovery of cognitive function after coronary artery bypass graft operations.

BACKGROUND: The effect of coronary artery bypass grafting (CABG) operations on cognition was examined after controlling for the operation, emotional state, preexisting cognitive impairment, and repeated experience with cognitive tests. METHODS: On-pump CABG patients (n=16), thoracic surgical patients (n=15), and a nonsurgical control group (n=15) were tested preoperatively, and at 1 and 8 weeks postoperatively, using a battery of cognitive tests and an emotional state assessment. Patient groups were similar in age, sex, level of education, and premorbid intelligence quotient score. Surgical group data were normalized against data from the nonsurgical control group before statistical analysis. RESULTS: CABG patients performed worse on every subtest before the operation, and this disadvantage persisted after the operation. Anxiety, depression, and stress were associated with impaired cognitive performance in the surgical groups 1 week after the operation: 44% of CABG patients and 33% of surgical control patients were significantly impaired; yet, by 8 weeks, nearly all patients had recovered to preoperative levels, with 25% of CABG and 13% of surgical control patients improving beyond their preoperative performance. CONCLUSIONS: Stress, anxiety, and depression impair cognitive performance in association with CABG and thoracic operations. Most patients recover to, or exceed, preoperative levels of cognition within 8 weeks. Thus, after controlling for nonsurgical factors, the prospects of a tangible improvement in cognition after CABG are high.

Brief report: The relationship between language skills, adaptive behavior, and emotional and behavior problems in pre-schoolers with autism.

This study investigated the relationship between structural language skills, and communication skills, adaptive behavior, and emotional and behavior problems in pre-school children with autism. Participants were aged 3-5 years with autism (n = 27), and two comparison groups of children with developmental delay without autism (n = 12) and typically developing children (n = 20). The participants were administered standardised tests of structural language skills, and parents completed the Vineland Adaptive Behavior Scales and the Developmental Behaviour Checklist. Results indicated that for children with autism, communication skills, and in particular receptive communication skills, were associated with social and daily living skills, and behavior problems. Receptive structural language skills were associated with expressive communication skills. There were no associations found between structural language skills and social or daily living skills, nor behavior problems. The results of this study suggest that communication skills are more closely linked to functional and behavioral outcomes in autism than structural language skills.

Morphological and syntactic skills in language samples of pre school aged children with autism: atypical development?

This study investigated whether children with autism have atypical development of morphological and syntactic skills, including whether they use rote learning to compensate for impaired morphological processing and acquire grammatical morphemes in an atypical order. Participants were children aged from 3-6 years who had autism (n = 17), developmental delay without autism (n = 7), and typically-developing children (n = 19). Language samples were taken from participants during the administration of the Autism Diagnostic Observation Schedule, and transcripts were coded using the Index of Productive Syntax, and for usage of Brown's grammatical morphemes. Participants were also administered an elicitation task requiring the application of inflections to non-words; the Wugs Task. The main finding of this study was that children with autism have unevenly developed morphological and syntactic sub-skills; they have skills which are a combination of intact, delayed, and atypical. It was also found that children with autism and children with developmental delays can acquire and use morphological rules. The implications of these findings are that, in order to maximize language acquisition for these children, clinicians need to utilize comprehensive language assessment tools and design interventions that are tailored to the child's strengths and weaknesses.

Subtle cognitive impairment in elders with Mini-Mental State Examination scores within the 'normal' range.

OBJECTIVE: The Mini-Mental State Examination (MMSE) is commonly used as a screening test for dementia, yet MMSE scores above the cut-off for dementia (24-30) are widely thought to have limited utility, particularly in older persons. The study investigates whether scores within this range can be indicative of pre-symptomatic levels of cognitive impairment. METHODS: Ninety-six community-dwelling older persons aged 62-89 years (mean = 75.2 years), who had obtained MMSE scores between 25 and 30, were tested on the computer-based Subtle Cognitive Impairment Test (SCIT). RESULTS: Compared with individuals who obtained a perfect score of 30 on the MMSE, individuals with scores of 28-29 made more errors on the SCIT, whereas those with scores of 25-27 on the MMSE made the most errors on the SCIT (F(2,94) = 9.84, p < 0.01). Individuals who made errors in the language (r(94) = -0.47, p < 0.01), attention (r(94) = 0.24, p < 0.05) and visual construction (r(94) = -0.27, p < 0.01) subtests of the MMSE were more likely to display impaired SCIT performance. CONCLUSIONS: The pattern of performance on the SCIT varied in a systematic way, depending on the MMSE subtest in which the errors were made, raising the possibility that there may be different subtypes of subtle cognitive impairment within the ostensibly normal population of older persons.

Impaired perceptual judgment at low blood alcohol concentrations.

Males and females show different patterns of cognitive impairment when blood alcohol concentrations (BACs) are high. To investigate whether gender differences persist at low BACs, cognitive impairment was tested in 21 participants (11 female, 10 male) using a brief computerized perceptual judgment task that provides error rate and response time data. Participants consumed a measured dose of alcohol (average peak BAC: females: 0.052 g/100 mL, males: 0.055 g/100 mL), and were tested at four time points spanning both the rising and falling limbs of the BAC curve, in addition to a prealcohol time point. Comparisons were made against performance of these same participants at equivalent time points in an alcohol-free control condition. Males and females displayed a trend toward slower responses and more errors, even when mildly intoxicated. These data indicate that cognitive function can be impaired at BACs that are below the legal limit for driving in most countries.