The time is "right:" Electrophysiology reveals right parietal electrode dominance in time perception.

In the present study, healthy undergraduates were asked to identify if a visual stimulus appeared on screen for the same duration as a memorized target (2 s) while event-related potentials (ERP) were recorded. Trials consisted of very short (1.25 s), short (1.6 s), target (2 s), long (2.5 s) or very long (3.125 s) durations, and a yes or no response was required on each trial. We examined behavioral response as signal detection (d') and response bias via a Generalized Accuracy Coefficient (GAC). We examined the mean amplitude as well as the change in amplitude of the initial Contingent Negative Variation (iCNV) and overall CNV (oCNV) and P350 (a P300-like component that follows stimulus extinction) potentials in paired, lateralized posterior electrodes. Results showed a bias to identifying shorter trials as the target more than longer trials via negative GAC scores. The slope and amplitudes of the iCNV and oCNV were consistently greater in right parietal electrodes. Also in right parietal electrodes, the iCNV correlated to d' scores while greater P350 amplitudes in the short condition correlated with more negative GAC scores. The results indicate dominance in the right hemisphere in temporal processing for durations exceeding 1 s. The P350 should also be studied further.

Research consent capacity varies with executive function and memory in Parkinson's disease.

BACKGROUND: We examined the association between cognitive domains and research consent capacity in PD. Our hypothesis was that research consent capacity is best predicted by executive function. METHODS: A cohort of 90 PD patients and 30 healthy older adults were administered the MacArthur Competence Assessment Tool for Clinical Research, Dementia Rating Scale-2, and the MoCA. Experts classified patients as either "capable" or "not capable" of providing informed consent to participate in two clinical trials. RESULTS: MacArthur Competence Assessment Tool for Clinical Research Reasoning scores for both clinical trial types were most associated with executive functions and delayed recall. As scores on these domains improved, the odds of an expert rating of "capable of consent" increased. CONCLUSIONS: These results extend our previous findings by demonstrating that memory and executive abilities appear closely associated with capacity when evaluated using either a structured interview or expert judgment of that interview.

Comparative accuracies of two common screening instruments for classification of Alzheimer's disease, mild cognitive impairment, and healthy aging.

BACKGROUND: The aim of this study was to compare the utility and diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) in the diagnosis of Alzheimer's disease (AD) and mild cognitive impairment (MCI) in a clinical cohort. METHODS: Three hundred twenty-one AD, 126 MCI, and 140 older adults with healthy cognition (HC) were evaluated using the MMSE, the MoCA, a standardized neuropsychologic battery according to the Consortium to Establish a Registry of Alzheimer's Disease (CERAD-NB), and an informant-based measure of functional impairment, the Dementia Severity Rating Scale (DSRS). Diagnostic accuracy and optimal cut-off scores were calculated for each measure, and a method for converting MoCA to MMSE scores is presented. RESULTS: The MMSE and MoCA offer reasonably good diagnostic and classification accuracy as compared with the more detailed CERAD-NB; however, as a brief cognitive screening measure, the MoCA was more sensitive and had higher classification accuracy for differentiating MCI from HC. Complementing the MMSE or the MoCA with the DSRS significantly improved diagnostic accuracy. CONCLUSION: The findings support recent data indicating that the MoCA is superior to the MMSE as a global assessment tool, particularly in discerning earlier stages of cognitive decline. In addition, we found that overall diagnostic accuracy improves when the MMSE or MoCA is combined with an informant-based functional measure. Finally, we provide a reliable and easy conversion of MoCA to MMSE scores. However, the need for MCI-specific measures is still needed to increase the diagnostic specificity between AD and MCI.

Predictors of Adherence to Continuous Positive Airway Pressure in Older Adults With Apnea and Amnestic Mild Cognitive Impairment.

BACKGROUND: Almost 60% of adults with amnestic mild cognitive impairment (aMCI) have obstructive sleep apnea (OSA). Treatment with continuous positive airway pressure (CPAP) may delay cognitive decline, but CPAP adherence is often suboptimal. In this study, we report predictors of CPAP adherence in older adults with aMCI who have increased odds of progressing to dementia, particularly due to Alzheimer's disease. METHODS: The data are from Memories 2, "Changing the Trajectory of Mild Cognitive Impairment with CPAP Treatment of Obstructive Sleep Apnea." Participants had moderate to severe OSA, were CPAP naïve, and received a telehealth CPAP adherence intervention. Linear and logistic regression models examined predictors. RESULTS: The 174 participants (mean age 67.08 years, 80 female, 38 Black persons) had a mean apnea-hypopnea index of 34.78, and 73.6% were adherent, defined as an average of ≥4 hours of CPAP use per night. Only 18 (47.4%) Black persons were CPAP adherent. In linear models, White race, moderate OSA, and participation in the tailored CPAP adherence intervention were significantly associated with higher CPAP use at 3 months. In logistic models, White persons had 9.94 times the odds of adhering to CPAP compared to Black persons. Age, sex, ethnicity, education, body mass index, nighttime sleep duration, daytime sleepiness, and cognitive status were not significant predictors. CONCLUSIONS: Older patients with aMCI have high CPAP adherence, suggesting that age and cognitive impairment should not be a barrier to prescribing CPAP. Research is needed to improve adherence in Black patients, perhaps through culturally tailored interventions.

Excessive daytime sleepiness is associated with poor medication adherence in adults with heart failure.

BACKGROUND: A relationship between excessive daytime sleepiness (EDS) and poor treatment adherence has been suspected but not confirmed. We hypothesized that medication adherence would be poorer in adults with heart failure (HF) and EDS and that cognitive status would be the mechanism of effect. METHODS AND RESULTS: A sample of 280 adults with chronic HF were enrolled into a prospective cohort comparison study. We identified a cohort with EDS and a control group without EDS and further divided both groups into those with and without mild cognitive decline. Data on medication adherence were obtained at baseline and 3 and 6 months by using the Basel Assessment of Adherence Scale. Regression analysis was used to clarify the contribution of EDS and cognition to medication adherence and to assess relationships over 6 months after adjusting for age, enrollment site, gender, race, functional class, depression, and premorbid intellect. At baseline, 62% of subjects were nonadherent to their medication regime. Nonadherence was significantly more common in those with EDS, regardless of cognitive status (P = .035). The odds of nonadherence increased by 11% for each unit increase in EDS (adjusted odds ratio 1.11; 95% confidence interval 1.05-1.19; P = .001). In longitudinal models, there was a 10% increase in the odds of nonadherence for each unit increase in EDS (P = .008). The only cognition measure significantly associated with medication adherence was attention (P = .047). CONCLUSIONS: Adults with HF and EDS are more likely to have problems adhering to their medication regimen than those without EDS, regardless of their cognitive status. Identifying and correcting factors that interfere with sleep may improve medication adherence.

A mixed methods study of symptom perception in patients with chronic heart failure.

BACKGROUND: Early heart failure (HF) symptoms are frequently unrecognized for reasons that are unclear. We explored symptom perception in patients with chronic HF. METHODS: We enrolled 36 HF out-patients into a longitudinal sequential explanatory mixed methods study. We used objectively measured thoracic fluid accumulation and daily reports of signs and symptoms to evaluate accuracy of detected changes in fluid retention. Patterns of symptom interpretation and response were explored in telephone interviews conducted every 2 weeks for 3-months. RESULTS: In this sample, 44% had a mismatch between objective and subjective fluid retention; younger persons were more likely to have mismatch. In interviews, two patterns were identified: those able to interpret and respond appropriately to symptoms were higher in decision-making skill and the quality of social support received. CONCLUSION: Many HF patients were poor at interpreting and managing their symptoms. These results suggest a subgroup of patients to target for intervention.

The content of lexical stimuli and self-reported physiological state modulate error-related negativity amplitude.

The Error-Related Negativity (ERN) and Correct-Response Negativity (CRN) are brief event-related potential (ERP) components-elicited after the commission of a response-associated with motivation, emotion, and affect. The Error Positivity (Pe) typically appears after the ERN, and corresponds to awareness of having committed an error. Although motivation has long been established as an important factor in the expression and morphology of the ERN, physiological state has rarely been explored as a variable in these investigations. In the present study, we investigated whether self-reported physiological state (SRPS; wakefulness, hunger, or thirst) corresponds with ERN amplitude and type of lexical stimuli. Participants completed a SRPS questionnaire and then completed a speeded Lexical Decision Task with words and pseudowords that were either food-related or neutral. Though similar in frequency and length, food-related stimuli elicited increased accuracy, faster errors, and generated a larger ERN and smaller CRN than neutral words. Self-reported thirst correlated with improved accuracy and smaller ERN and CRN amplitudes. The Pe and Pc (correct positivity) were not impacted by physiological state or by stimulus content. The results indicate that physiological state and manipulations of lexical content may serve as important avenues for future research. Future studies that apply more sensitive measures of physiological and motivational state (e.g., biomarkers for satiety) or direct manipulations of satiety may be a useful technique for future research into response monitoring.

Levels-of-processing effect on frontotemporal function in schizophrenia during word encoding and recognition.

OBJECTIVE: Patients with schizophrenia improve episodic memory accuracy when given organizational strategies through levels-of-processing paradigms. This study tested if improvement is accompanied by normalized frontotemporal function. METHOD: Event-related blood-oxygen-level-dependent functional magnetic resonance imaging (fMRI) was used to measure activation during shallow (perceptual) and deep (semantic) word encoding and recognition in 14 patients with schizophrenia and 14 healthy comparison subjects. RESULTS: Despite slower and less accurate overall word classification, the patients showed normal levels-of-processing effects, with faster and more accurate recognition of deeply processed words. These effects were accompanied by left ventrolateral prefrontal activation during encoding in both groups, although the thalamus, hippocampus, and lingual gyrus were overactivated in the patients. During word recognition, the patients showed overactivation in the left frontal pole and had a less robust right prefrontal response. CONCLUSIONS: Evidence of normal levels-of-processing effects and left prefrontal activation suggests that patients with schizophrenia can form and maintain semantic representations when they are provided with organizational cues and can improve their word encoding and retrieval. Areas of overactivation suggest residual inefficiencies. Nevertheless, the effect of teaching organizational strategies on episodic memory and brain function is a worthwhile topic for future interventional studies.

Organization of semantic category exemplars in schizophrenia.

Semantic memory was investigated in 27 individuals with schizophrenia and 30 healthy controls using an animal similarity judgment and organization test with reduced retrieval demands. Participants arranged 12 common animal names according to similarity on a computer screen and provided verbal descriptions of organizational strategies. Distance between each animal pair was compared to the number of shared semantic attributes between the pairs (e.g., size, diet, habitat). The three primary organizational strategies included single animals not related to other exemplars, isolated clusters of animals that shared a single strategic relationship (e.g., pets), and overlapping clusters that combined more than one strategic relationship (e.g., cats and mammals). A strong negative correlation was observed between distance ratings and number of shared semantic attributes, confirming that semantic features related to visual distances in both groups. Animal pairs that shared few semantic attributes were placed in closer proximity in the schizophrenia group, whereas the groups placed animal pairs sharing more features equidistantly. Analyses of clustering strategies revealed a double dissociation, with patients relying on isolated, non-overlapping clusters and controls producing more overlapping semantic clusters. Results suggest that performance differences on semantic tasks with limited retrieval demands in schizophrenia relate to difficulties utilizing higher-order categorization strategies.

Levels-of-processing effect on word recognition in schizophrenia.

BACKGROUND: Individuals with schizophrenia have difficulty organizing words semantically to facilitate encoding. This is commonly attributed to organizational rather than semantic processing limitations. By requiring participants to classify and encode words on either a shallow (e.g., uppercase/lowercase) or deep level (e.g., concrete/abstract), the levels-of-processing paradigm eliminates the need to generate organizational strategies. METHODS: This paradigm was administered to 30 patients with schizophrenia and 30 healthy comparison subjects to test whether providing a strategy would improve patient performance. RESULTS: Word classification during shallow and deep encoding was slower and less accurate in patients. Patients also responded slowly during recognition testing and maintained a more conservative response bias following deep encoding; however, both groups showed a robust levels-of-processing effect on recognition accuracy, with unimpaired patient performance following both shallow and deep encoding. CONCLUSIONS: This normal levels-of-processing effect in the patient sample suggests that semantic processing is sufficiently intact for patients to benefit from organizational cues. Memory remediation efforts may therefore be most successful if they focus on teaching patients to form organizational strategies during initial encoding.

Memory-delineated subtypes of schizophrenia: relationship to clinical, neuroanatomical, and neurophysiological measures.

Memory performance was examined in patients with schizophrenia to determine whether subgroups conforming to cortical and subcortical dementias could be identified and, if so, whether subgroups differed on clinical, neuroanatomical, and neurophysiological measures. A cluster analysis of California Verbal Learning Test performance classified patients into 3 subgroups. Two groups exhibited memory deficits consistent with the cortical-subcortical distinction, whereas 1 group was unimpaired. Cortical patients tended to be male, and they had earlier illness onset, reduced temporal lobe gray matter, and hypometabolism. Subcortical patients had ventricular enlargement and more negative symptoms. Unimpaired patients had fewer negative symptoms and dorsal medial prefrontal hypermetabolism. The authors conclude that categorizing patients on the basis of memory deficits may yield neurobiologically meaningful disease subtypes.

Cognitive impairment and PD patients' capacity to consent to research.

OBJECTIVE: To examine how cognitive impairment affects Parkinson disease (PD) patients' research consent capacity. METHODS: A cross-sectional study of 90 patients with PD, divided using Mattis Dementia Rating Scale-2 scores into 3 groups of 30 (normal, borderline, and impaired), and 30 neurologically normal older adults completed 2 capacity interviews (an early-phase randomized and controlled drug trial and a sham-controlled surgical implantation of genetic tissue) using the MacArthur Competence Assessment Tool for Clinical Research. Expert clinicians used the interviews to classify the patients as either capable or not capable of providing their own informed consent. These judgments were compared with performance on the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE). RESULTS: Cognitively normal PD patients typically scored well on the capacity measures. In contrast, patients with impaired cognition were not capable of providing their own informed consent: 17% (5/30) on the drug trial and 3% (1/30) on the surgery trial were judged capable. Patients with borderline impairment showed adequate performance on measures of appreciation and reasoning, but impaired performance on understanding the drug trial compared with normal controls and normal PD patients, and on understanding the surgery trial compared with normal controls. Sixty-seven percent (20/30) on the drug trial and 57% (17/30) on the surgery trial were judged capable of consent. Receiver operating characteristic analyses showed that the MMSE and MoCA could detect the likelihood of impaired capacity, with the MoCA demonstrating greater sensitivity. CONCLUSIONS: PD patients with borderline cognitive impairment have impairments in their decisional capacity. The MoCA may be useful to identify the patients at risk of impaired capacity.

Patterns of Change in Cognitive Function over Six Months in Adults with Chronic Heart Failure.

Few investigators have studied cognition over time in adults with heart failure (HF). A battery of neuropsychological tests was administered to 279 adults with chronic systolic or diastolic HF at baseline, three and six months. Growth mixture modeling (GMM) was used to model the measure anticipated to be most sensitive, the digit symbol substitution task (DSST). We describe how and why the DSST patterns change over time. Other measures of cognition were examined to identify consistency with the DSST patterns. The sample was predominantly male (63.2%), Caucasian (62.7%), mean age 62 years. The best fit GMM revealed two trajectories of DSST scores: Average processing speed group (40.5%) and Below Average processing speed (59.9%). Neither group changed significantly over the six month study. Other measures of cognition were consistent with the DSST patterns. Factors significantly associated with increased odds of being in the Below Average processing speed group included older age, male gender, Non-Caucasian race, less education, higher ejection fraction, high comorbid burden, excessive daytime sleepiness, and higher BMI. As some of the factors related to cognitive impairment are modifiable, research is needed to identify interventions to preserve and improve cognition in these patients.

Temporal order memory differences in Alzheimer's disease and vascular dementia.

Determining the order of events is essential for accurate memory recollection: an ability previously linked to both frontal and medial temporal functioning. Frontal-subcortical and medial temporal dysfunction typify vascular dementia (VaD) and Alzheimer's disease (AD), respectively. Therefore, we assessed patients' ordering abilities using a novel sequencing task that progressively increased memory load. VaD patients made more errors and selected more previously encountered stimuli than did AD. Curve analysis revealed a general decline in ordering for VaD whereas error production in AD is more dependent on memory load. These findings generally support the role of frontal-subcortical functioning in temporal order memory.

Physician utilization by insurance type among youth with type 2 diabetes.

OBJECTIVE: To evaluate the relationship between insurance type (Medicaid vs private insurance) and access to physician care for youth with type 2 diabetes mellitus by quantifying whether these youth saw a physician during the year before their first diabetes documentation. STUDY DESIGN: Retrospective cohort study. METHODS: Youth with Medicaid or private insurance aged 5 to 19 years with type 2 diabetes were identified by an electronic medical record review. The first indication of type 2 diabetes defined the index date. Youth with type 1 diabetes and female patients with polycystic ovaries were excluded. Descriptive statistics evaluated differences in office visits before the index date between patients with the 2 insurance types. Multivariate logistic regression analysis evaluated the likelihood of having an office visit during the year before the index date among youth with Medicaid versus private insurance, controlling for youth characteristics. RESULTS: Of 2496 included youth, 400 (16.0%) had Medicaid coverage. More than 60% were female, the mean age was 14.5 years, and 68.8% were obese. On average, youth had 1.9 office visits during the year before the index date. Medicaid-covered youth were not significantly less likely to have had an office visit (odds ratio, 0.77; P = .09) or fewer total office visits (incident rate ratio, 1.13; P = .16) during the year before the index date. CONCLUSIONS: The likelihood of youth with type 2 diabetes and a source of physician care having a physician office visit during the year before the index date did not differ between patients with Medicaid versus private insurance. This suggests that the amount of physician care before diagnosis of type 2 diabetes does not differ for Medicaid-covered youth if they can establish a source of care. Additional research is investigating whether physician access before diagnosis is associated with access to diabetes-related care after diagnosis.

Retrospective assessment of rehabilitation outcome after traumatic brain injury: development and utility of the functional independence level.

OBJECTIVE: To develop a measure suitable for retrospective analysis of qualitative brain injury outcome data, the Functional Independence Level (FIL), and document its reliability, validity, and utility. DESIGN: Retrospective analysis of existing records, with inclusion based on availability of records, and quantitative or qualitative documentation of functional status at a minimum of 1.5 years after injury. SETTING: Statewide acute and postacute rehabilitation facilities, as part of a State Head Injury Program. PARTICIPANTS: A total of 338 individuals, with documented moderate to severe traumatic brain injury; primarily males ages 16 to 45. MAIN OUTCOME MEASURES: Disability Rating Scale (DRS) at discharge from primary rehabilitation, Living Situation and Functional Independence Level coded from information in postacute rehabilitation reports, at an average of approximately 6 years after injury. RESULTS: Inter-rater reliability coefficients for FIL ratings extracted from rehabilitation records, and between retrospective and in vivo assessments were highly significant. DRS scores at discharge from primary rehabilitation predicted a significant amount of variance in FIL scores at an average of 5 years after injury, and DRS scores remained a stable and significant predictor of FIL scores as the time period between discharge from rehabilitation and outcome ratings increased to 10 years after injury. FIL ratings were significantly lower for individuals living in residential facilities than those living with their families, as compared to living alone. CONCLUSIONS: The FIL is a reliable and useful tool for retrospective and prospective assessments of rehabilitation outcome. Gains made during primary rehabilitation by people with severe traumatic brain injury are generally maintained at long-term follow up. Retrospective ratings using the DRS and FIL can help guide postacute rehabilitation planning within state or regional head injury programs.

Motor vehicle collision factors influence severity and type of TBI.

PRIMARY OBJECTIVE: To analyse the relationship between motor vehicle collision factors and TBI. RESEARCH DESIGN: Retrospective design analysed the difference between the types of brain injuries sustained in distinct collision configurations. METHODS AND PROCEDURES: Medical charts and police accident reports were reviewed for individuals sustaining TBI in 168 motor vehicle collisions between 1985-1998. MAIN OUTCOMES AND RESULTS: Lateral collisions and collisions involving contact with a fixed object were associated with the most severe brain injuries. Analysis of safety restraints revealed that seatbelts not only reduce the probability of injury, but they also mediate the severity of brain injury when it is sustained. CONCLUSIONS: Future research should focus the prevention of injury by better defining the minimum physical thresholds at which brain injury might be sustained and the mechanisms by which these thresholds are achieved during natural collisions.