Colette M. Smart

Implementation of subjective cognitive decline criteria in research studies

Subjective cognitive decline (SCD) manifesting before clinical impairment could serve as a target population for early intervention trials in Alzheimers disease (AD). A working group, the Subjective Cognitive Decline Initiative (SCD‐I), published SCD research criteria in the context of preclinical AD. To successfully apply them, a number of issues regarding assessment and implementation of SCD needed to be addressed.

A case of locked-in syndrome complicated by central deafness.

Background A 53-year-old male with a history of hypertension, diabetes mellitus, and factor V deficiency presented to an emergency room with progressively increasing headache, slurred speech, and left upper extremity weakness. Over the previous 3 months, he had been receiving warfarin for prophylaxis of deep venous thrombosis following knee surgery. After presentation and an initial period of coma, he became tetraplegic and anarthric, requiring intubation and ventilatory assistance.Investigations Neurological examination, CT scan, electroencephalogram, brainstem auditory and visual evoked potential studies, neuropsychological assessment and functional MRI studies.Diagnosis Locked-in syndrome following ventral pontine hemorrhage, complicated by central deafness secondary to extension of the lesion to the inferior colliculus.Management Development of an augmentative communication system designed to exploit the patients preserved cognitive and motor functions.

Recent advances in behavioral assessment of individuals with disorders of consciousness.

Purpose of reviewThe burden of proof for establishing diagnosis and prognosis in patients with disorders of consciousness lies with behavioral assessment methods. The current review discusses recent advances in understanding the strengths and weaknesses of this methodology. Recent findingsBehavioral assessment methods remain the ‘gold standard’ for establishing diagnosis and prognosis in patients with disorders of consciousness, although their psychometric integrity and clinical utility remain largely unproven. While the Glasgow Coma Scale maintains its standing in the trauma setting, there are ongoing concerns regarding testing confounds and interrater reliability. The Full Outline of UnResponsiveness, an emerging alternative, is more sensitive to detection of locked-in syndrome but may fail to identify patients in the minimally conscious state. Recent studies investigating the relationship between behavioral and neurophysiologic measures of conscious awareness have revealed important dissociations between behavioral response profiles and corresponding neural activity. SummaryFurther research is needed on the psychometric properties of existing behavioral assessment methods for disorders of consciousness. Although dissociations between behavioral and neurophysiologic findings caution against overreliance on behavioral metrics for detection of conscious awareness, we expect there will be increased effort toward combining these methodologies to increase diagnostic accuracy and prognostic specificity in patients with disorders of consciousness.

BLINK TO VISUAL THREAT DOES NOT HERALD CONSCIOUSNESS IN THE VEGETATIVE STATE

The blink response to visual threat is a standard bedside method for testing visual processing. In response to a sudden gesture directed toward the eyes, a person with a normal blink response will promptly contract both orbicularis oculi muscles to close the eyelids momentarily. There is no consensus as to whether blinking to visual threat (BVT) is purely reflex1 or a cognitively mediated behavior that heralds consciousness; i.e., is incompatible with the diagnosis of the vegetative state (VS).2,3 Some authors stated that “one should be extremely cautious in making the diagnosis of the VS when there is … response to threatening gestures.”4 Others stated that “react(ion) to visual threat” is a “compatible but atypical feature” of VS.5 Similarly, other guidelines stated that the “threat response is usually absent” in VS.6 Finally, BVT was not mentioned in some workgroup criteria on the minimally conscious state.7 The aim of the study was to determine the incidence of BVT in patients whose clinical features are in all other respects typical of the VS, as assessed by means of validated testing.7 We also investigated whether the presence of BVT in patients considered vegetative is predictive of recovery of consciousness. ### Methods. The BVT was assessed (four …

Use of MMPI-2 to predict cognitive effort: A hierarchically optimal classification tree analysis

Neuropsychologists routinely rely on response validity measures to evaluate the authenticity of test performances. However, the relationship between cognitive and psychological response validity measures is not clearly understood. It remains to be seen whether psychological test results can predict the outcome of response validity testing in clinical and civil forensic samples. The present analysis applied a unique statistical approach, classification tree methodology (Optimal Data Analysis: ODA), in a sample of 307 individuals who had completed the MMPI-2 and a variety of cognitive effort measures. One hundred ninety-eight participants were evaluated in a secondary gain context, and 109 had no identifiable secondary gain. Through recurrent dichotomous discriminations, ODA provided optimized linear decision trees to classify either sufficient effort (SE) or insufficient effort (IE) according to various MMPI-2 scale cutoffs. After of an initial, complex classification tree, the Response Bias Scale (RBS) took precedence in classifying cognitive effort. After removing RBS from the model, Hy took precedence in classifying IE. The present findings provide MMPI-2 scores that may be associated with SE and IE among civil litigants and claimants, in addition to illustrating the complexity with which MMPI-2 scores and effort test results are associated in the litigation context.

Mindfulness Training for Older Adults with Subjective Cognitive Decline: Results from a Pilot Randomized Controlled Trial

INTRODUCTION Subjective cognitive decline (SCD) in older adults is a condition with a complex phenomenology and diverse etiologies including (but not limited to) mood, personality, and health concerns, as well as biomarkers of preclinical Alzheimers disease such as amyloid-β deposition and gray matter volume loss. Approximately 60% of affected persons are estimated to decline to Alzheimers dementia. Regardless of etiology, persons with SCD may be optimal targets for early intervention. OBJECTIVE To ascertain the feasibility and impact of mindfulness training (MT) as an early intervention in persons with SCD. METHODS Using a single-blind, randomized controlled trial design, older adults with (n = 14) and without (n = 22) SCD were randomized to either MT or a control condition of psychoeducation (PE) on cognitive aging. EEG/ERP (specifically, the P3 component), structural MRI, and self-report measures of psychological functioning were obtained within 4 weeks prior to and within 2 weeks following intervention. RESULTS MT resulted in decreased reaction time intra-individual variability for all participants, with a selective increase in the P3 event-related component for those with SCD. Compared with PE, MT also resulted in an increase in percent volume brain change in structural MRI. Finally, all SCD participants reported a decrease in cognitive complaints and increase in memory self-efficacy following intervention. DISCUSSION Results suggest that MT is a feasible early intervention in persons with SCD. Longer-term follow-up with larger sample sizes will determine whether MT can slow the rate of decline in persons who may be at risk for Alzheimers dementia.

Attention capacity and self-report of subjective cognitive decline: a P3 ERP study.

Subjective cognitive decline (SCD) has recently been proposed as the earliest stage of pathologic cognitive decline in older adults. Longitudinal research suggests that many individuals with SCD go on to develop mild cognitive impairment or Alzheimers disease. However, those with SCD typically appear normal on standardized neuropsychological testing, and as of yet there are no reliable objective measures discriminating those with SCD from healthy peers. Two groups of healthy older adults (ages 65-80), who self-identified as being with (n=17) or without SCD (n=23), completed self-report measures and objective measures of cognition. Groups did not differ on demographic variables, estimated cognitive reserve, or clinical neuropsychological testing. However, self-identifying as having SCD predicted clear differences in the P3 event-related potential in response to an attention control task, over and above any contributions from mood, anxiety, or neuroticism. Results suggest that using direct neural measures of information processing might be useful where standardized clinical tools are insensitive in those with SCD.

Subjective Cognitive Decline in Preclinical Alzheimer's Disease

Older adults with subjective cognitive decline (SCD) in the absence of objective neuropsychological dysfunction are increasingly viewed as at risk for non-normative cognitive decline and eventual progression to Alzheimers disease (AD) dementia. The past decade has witnessed tremendous growth in research on SCD, which may reflect the recognition of SCD as the earliest symptomatic manifestation of AD. Yet methodological challenges associated with establishing common assessment and classification procedures hamper the construct. This article reviews essential features of SCD associated with preclinical AD and current measurement approaches, highlighting challenges in harmonizing study findings across settings. We consider the relation of SCD to important variables and outcomes (e.g., AD biomarkers, clinical progression). We also examine the role of self- and informant-reports in SCD and various psychological, medical, and demographic factors that influence the self-report of cognition. We conclude with a discussion of intervention strategies for SCD, ethical considerations, and future research priorities.

The impact of subjective cognitive decline on Iowa Gambling Task performance.

OBJECTIVE To ascertain whether the Iowa Gambling Task (IGT) could be used to detect and identify measurable cognitive differences between older adults with subjective cognitive decline (SCD) as compared with healthy older controls (HC). METHOD Older adults with self-identified SCD and age-matched controls completed a comprehensive neuropsychological assessment battery including the clinical version of the IGT, as well as self-report measures of mood and personality. RESULTS The groups did not differ on clinically normed scores on the IGT. However, the groups did differ in the specific decks chosen as they progressed through the task, with the SCD group choosing the advantageous, high loss-frequency deck (Deck C) more often toward the end of the task. Using hierarchical Bayesian parameter estimation, we show that the prospect valence learning (PVL) model outperforms the expectancy valence learning (EVL) model in parsimoniously accounting for task performance by both groups. The PVL model explains the difference in deck choices between groups as being because of an underlying difference in their learning rate, with the SCD group emphasizing the current outcome over past outcomes more than the HC group. CONCLUSIONS Behavioral results indicate measureable differences in risky decision making in older adults with SCD as compared with healthy controls. Modeling results allow us to interpret this difference as potentially being because of rapid forgetting of trial-to-trial information. This work furthers our understanding of SCD, while demonstrating the use of computational modeling in the interpretation of neuropsychological data.

Characteristics of Healthy Older Adults that Influence Self-rated Cognitive Function

OBJECTIVES We sought to clarify the nature of self-reported cognitive function among healthy older adults by considering the short-term, within-person association (coupling) of subjective cognitive function with objective cognitive performance. We expected this within-person coupling to differ between persons as a function of self-perceived global cognitive decline and depression, anxiety, or neuroticism. METHODS This was an intensive measurement (short-term longitudinal) study of 29 older adult volunteers between the ages of 65 and 80 years without an existing diagnosis of dementia or mild cognitive impairment. Baseline assessment included neuropsychological testing and self-reported depression, anxiety, and neuroticism, as well as self- and informant-reported cognitive decline (relative to 10 years previously). Intensive within-person measurement occasions included subjective ratings of cognitive function paired with performance on a computerized working memory (n-back) task; each participant attended four or five assessments separated by intervals of at least one day. Statistical analysis was comprised of multilevel linear regression. RESULTS Comparison of models suggested that both neuroticism and self-rated cognitive decline explained unique variance in the within-person, across-occasion coupling of subjective cognitive function with objective working memory performance. CONCLUSIONS Self-ratings of cognition may accurately reflect day-to-day variations in objective cognitive performance among older adults, especially for individuals lower in neuroticism and higher in self-reported cognitive decline. Clinicians should consider these individual differences when determining the validity of complaints about perceived cognitive declines in the context of otherwise healthy aging. (JINS, 2018, 24, 57-66).