Managing cognitive impairment and its impact in multiple sclerosis: An Australian multidisciplinary perspective.

Cognitive impairment in multiple sclerosis (MS) affects approximately 40-70% of patients and can have varying degrees of severity. Even mild cognitive impairment can impact on quality of life and productivity. Despite this, patients are not routinely screened or monitored for cognitive impairment in Australia due to a range of issues, with time and space being the main limiting factors. This Australian multidisciplinary perspective provides recommendations on cognition management in Australia. It gives a broad overview of cognition in MS, advice on the screening and monitoring tools available to clinicians, and strategies that can be implemented in clinics to help monitor for cognitive impairment in patients with MS. We suggest a routine baseline assessment and multidomain cognitive battery in regular intervals; a change should trigger a thorough investigation of the cause.

Mild Cognitive Impairment Subtypes in Older People With Depressive Symptoms: Relationship With Clinical Variables and Hippocampal Change.

AIMS: To examine the rates and clinical characteristics of mild cognitive impairment (MCI) in older people with depressive symptoms and to determine the relative contribution of hippocampal volume and MCI to memory change. METHOD: One hundred and fifty-two participants with lifetime Major Depression and remitted or mild symptoms and 28 healthy controls underwent psychiatric and neuropsychological assessments. Magnetic resonance imaging was also conducted in a subset of the patients (n = 81) and healthy controls (n = 18). RESULTS: MCI was diagnosed in 75.7% of the patients and was associated with increasing age, medical burden, vascular risk factors, later age of depression onset and smaller hippocampi. Multiple regression showed that both hippocampal volume and MCI diagnosis mediate memory performance in depression. CONCLUSIONS: MCI occurs in older adults with a history of depression and is not simply due to symptom severity. Memory change is linked to underlying hippocampal atrophy in this patient group.

Randomized controlled trial of a healthy brain ageing cognitive training program: effects on memory, mood, and sleep.

BACKGROUND: With the rise in the ageing population and absence of a cure for dementia, cost-effective prevention strategies for those 'at risk' of dementia including those with depression and/or mild cognitive impairment are urgently required. OBJECTIVE: This study evaluated the efficacy of a multifaceted Healthy Brain Ageing Cognitive Training (HBA-CT) program for older adults 'at risk' of dementia. METHODS: Using a single-blinded design, 64 participants (mean age = 66.5 years, SD = 8.6) were randomized to an immediate treatment (HBA-CT) or treatment-as-usual control arm. The HBA-CT intervention was conducted twice-weekly for seven weeks and comprised group-based psychoeducation about cognitive strategies and modifiable lifestyle factors pertaining to healthy brain ageing, and computerized cognitive training. RESULTS: In comparison to the treatment-as-usual control arm, the HBA-CT program was associated with improvements in verbal memory (p = 0.03), self-reported memory (p = 0.03), mood (p = 0.01), and sleep (p = 0.01). While the improvements in memory (p = 0.03) and sleep (p = 0.02) remained after controlling for improvements in mood, only a trend in verbal memory improvement was apparent after controlling for sleep. CONCLUSION: The HBA-CT program improves cognitive, mood, and sleep functions in older adults 'at risk' of dementia, and therefore offers promise as a secondary prevention strategy.

Caregiver burden in mild cognitive impairment.

OBJECTIVES: We aimed to compare the rates of burden amongst caregivers of participants with mild cognitive impairment (MCI), compared to a control group. We also aimed to identify factors in both the caregiver and patient that are associated with significant levels of burden. METHOD: This was a cross-sectional study. Sixty-four participants with MCI, 36 control-participants and their respective caregivers/informants were recruited to a university research clinic. The proportion of those who showed clinically significant levels of burden was determined by a Zarit Burden Interview score of >21. The associations of burden in MCI-caregivers were calculated in the following categories; participant characteristics (including depressive symptoms, cognition and informant ratings of cognitive and behavioural change); caregiver characteristics; and the caregiving context. Multivariate analyses were performed to examine the relative contribution of individual variables to burden amongst MCI-caregivers. RESULTS: We found that 36% of MCI-caregivers reported clinically significant levels of burden, twice that of the control informant group. Participant behavioural problems contribute most to burden, with participant depression and possibly cognition also having a significant association. CONCLUSION: Caregiver burden is a considerable problem in MCI and shares some of the same characteristics as caregiver burden in dementia, namely a strong association with challenging behaviours in the patient. This has implications for further research and intervention studies.

Cognitive training enhances pre-attentive neurophysiological responses in older adults 'at risk' of dementia.

BACKGROUND: With predicted increases in dementia incidence, interventions targeting neuroplasticity and neuroprotection are required. Cognitive Training (CT) is an intervention which has been shown to improve aspects of cognition, but the pathophysiological mechanisms contributing to its efficacy are unknown. OBJECTIVE: We aimed to explore the neurobiological correlates of CT using Mismatch Negativity (MMN), a neurophysiological marker of pre-attentive information processing, which in turn, is postulated to underpin higher-order cognitive processes. METHODS: As part of a larger randomized controlled trial, forty 'at risk' (i.e., mild cognitive impairment or late-life depression) participants aged 51-79 years underwent neurophysiological, neuropsychological, and psychiatric assessments before and after a multi-faceted seven-week CT program or a 'treatment-as-usual' seven-week waitlist period. RESULTS: The treatment group demonstrated significantly increased fronto-central MMN responses (p < 0.05), as well as improved phonemic verbal fluency (p < 0.05) and decreased self-rated memory difficulties (p < 0.05) following CT, in comparison to the waitlist control group. However, there were no significant correlations between enhanced MMN and cognitive/psychosocial outcomes. CONCLUSIONS: Results from this preliminary investigation indicate that CT is associated with enhanced neurophysiological mechanisms suggestive of improved pre-attentive processing, which may reflect alterations in underlying neurobiology. Further research is warranted to confirm these findings, to explicate whether CT is associated with restorative or compensatory neuroplastic processes and to determine whether MMN is a useful biomarker for treatment response.

Accelerated long-term forgetting of verbal information in unilateral temporal lobe epilepsy: Is it related to structural hippocampal abnormalities and/or incomplete learning?

The factors contributing to accelerated long-term forgetting (ALF) are not yet clear. In this study, a 12-item word list was presented repeatedly to 23 patients with temporal lobe epilepsy (TLE) and 27 control participants (NC) until it was recalled completely on two consecutive trials or until 12 trials were undertaken. Compared to NCs, patients with hippocampal lesions and those who failed to learn the list showed ALF by one day post learning, but the alternative patient groups also showed ALF when tested after seven days. Overall, our findings suggest that in patients with TLE neither a preserved hippocampus nor intact learning protects against ALF.

Clinical and Cognitive Correlates of Structural Hippocampal Change in "At-Risk" Older Adults.

With estimates of dementia expected to rise over the coming decades, there is interest in understanding the factors associated with promoting neuroprotection and limiting neurodegeneration. In this study, we examined the change in the volume of the hippocampus over a 2-month period in 34 older people "at risk" of cognitive decline (mean age = 66.8 years, 38% male). Factors that were examined included cognitive reserve, neuropsychological functioning, depression as well as a lifestyle (cognitive training) intervention. The results showed that over a 2-month period, increases in hippocampal size were associated with having higher premorbid intellect, greater occupational attainment, superior memory, and higher levels of functioning. Conversely, depression and disability were associated with decreases in hippocampal volume. Cognitive training was not associated with changes in hippocampal volume. These findings suggest that factors associated with cognitive reserve, cognition and depression may play an integral pathophysiological role in determining hippocampal volumes in "at-risk" older adults.

Glutathione relates to neuropsychological functioning in mild cognitive impairment.

BACKGROUND: Mild cognitive impairment (MCI) represents an at-risk state for Alzheimer's disease in which underlying pathophysiological mechanisms could be delineated. Oxidative stress has been implicated in Alzheimer's disease and can be measured by levels of the antioxidant glutathione. This study aims to assess in vivo levels of glutathione via proton magnetic resonance spectroscopy in patients with MCI and to determine how glutathione relates to cognitive decline. METHODS: Fifty-four patients with MCI and 41 healthy control subjects underwent proton magnetic resonance spectroscopy in conjunction with medical, psychiatric, and neuropsychological assessments. The concentration of glutathione was measured in the anterior and posterior cingulate, and ratios of glutathione were calculated relative to creatine. Neuropsychological performance was assessed across the domains of processing speed, learning, memory, and executive functions. RESULTS: In comparison with control subjects, patients with MCI had significantly elevated ratios of glutathione in the anterior (t = -2.2, P = .03) and posterior (t = -2.9, P = .005) cingulate. Higher levels of anterior cingulate glutathione were related to neuropsychological decrements on tests of executive functions. Elevated posterior cingulate glutathione was associated with poorer memory consolidation. CONCLUSION: This study has shown for the first time that MCI is associated with increased glutathione in the cingulate, which in turn relates to neuropsychological performance. This finding may be indicative of an early compensatory or neuroprotective response, and the role of glial cells and glutathione enzymes requires delineation. Longitudinal studies examining the utility of glutathione as a marker for cognitive decline are now required.

Improving memory in Parkinson's disease: a healthy brain ageing cognitive training program.

This study aimed to evaluate the efficacy of a multifactorial 'healthy brain ageing cognitive training program' for Parkinson's disease. Using a single-blinded waitlist control design, 50 participants with Parkinson's disease were recruited from the Brain & Mind Research Institute, Sydney, Australia. The intervention encompassed both psychoeducation and cognitive training; each component lasted 1-hour. The 2-hour sessions were delivered in a group format, twice-weekly over a 7-week period. Multifactorial psychoeducation was delivered by a range of health professionals. In addition to delivering cognitive strategies, it targeted depression, anxiety, sleep, vascular risk factors, diet, and exercise. Cognitive training was computer-based and was conducted by clinical neuropsychologists. The primary outcome was memory. Secondary outcomes included other aspects of cognition and knowledge pertaining to the psychoeducation material. Results demonstrated that cognitive training was associated with significant improvements in learning and memory corresponding to medium to large effect sizes. Treatment was also associated with medium effect size improvements in knowledge. Although the study was limited by the lack of randomized allocation to treatment and control groups, these findings suggest that a healthy brain ageing cognitive training program may be a viable tool to improve memory and/or slow cognitive decline in people with Parkinson's disease. It also appeared successful for increasing awareness of adaptive and/or compensatory cognitive strategies, as well as modifiable risk factors to optimize brain functioning.

Reduced mismatch negativity in mild cognitive impairment: associations with neuropsychological performance.

Mild cognitive impairment (MCI) refers to a transitory state between healthy aging and dementia. Biomarkers are needed to facilitate early identification of MCI and predict progression to dementia. One potential neurophysiological biomarker, mismatch negativity (MMN), is an event-related potential reflecting fundamental, pre-attentive cognitive processes. MMN is reduced in normal aging and dementia and in neuropsychiatric samples and is associated with verbal memory deficits and poor executive functioning. This study aimed to investigate auditory MMN and its relationship to neuropsychological performance in MCI. Twenty-eight MCI participants and fourteen controls, aged ≥50 years, underwent neurophysiological and neuropsychological assessment, and completed questionnaires pertaining to disability. Relative to controls, the MCI group demonstrated reduced temporal MMN amplitude (p < 0.01). Reduced right temporal MMN was significantly associated with poorer verbal learning (r = 0.496; p < 0.01) and reduced left temporal MMN was significantly associated with increased self-reported disability (r = -0.419; p < 0.05). These results indicate that patients with MCI exhibit altered pre-attentive information processing, which in turn is associated with memory and psychosocial deficits. These findings overall suggest that MMN may be a viable neurophysiological biomarker of underlying disease in this 'at risk' group.

Reduced temporal mismatch negativity in late-life depression: an event-related potential index of cognitive deficit and functional disability?

BACKGROUND: Depression in older people has been consistently linked with a variety of neurobiological brain changes. One measure of preattentive auditory processing, the mismatch negativity (MMN), has not been previously examined in late-life depression. This study examined MMN elicited by duration deviant stimuli in older people with lifetime depression, and explored its relationship with neuropsychological functioning and disability. METHODS: Twenty-two older health-seeking patients (mean age=65.2 years) with lifetime major depressive disorder and twelve age and sex-matched control participants (mean age=64.6 years) completed detailed clinical and neuropsychological assessments and the WHO-DAS as a measure of disability. MMN amplitudes were elicited using a two-tone passive auditory oddball paradigm and measured at frontal (Fz), central (Cz) and temporal (left and right mastoid: M1 and M2, respectively) sites. RESULTS: Patients with depression demonstrated reduced mean MMN amplitude at temporal (M1, t=3.1, p<0.01; M2, t=3.8, p<0.01), but not fronto-central sites. Reduced temporal MMN amplitudes did not relate to depressive symptom severity, but were associated with reduced semantic fluency and greater self-rated functional disability. LIMITATIONS: The contribution of depressive symptom 'state' and medications on MMN need to be considered. CONCLUSIONS: Reduced mean amplitudes of mastoid MMN in older patients with lifetime depression may reflect underlying brain changes. This preattentive marker relates to neuropsychological probes of frontotemporal circuits, and importantly, is associated with disability. Longitudinal analysis of MMN in this group will determine its predictive utility as a biomarker for ongoing cognitive decline and illness chronicity.

Using informant reports to detect cognitive decline in mild cognitive impairment.

BACKGROUND: The use of informant rating scales in older adults at risk of dementia may assist with early detection and intervention strategies. This study aims to evaluate whether informants rate greater cognitive change in patients with mild cognitive impairment (MCI) compared to cognitively intact individuals, and to determine the relationship between informant ratings of cognitive change and neuropsychological performance. METHODS: One hundred and nine health-seeking older adults underwent clinical and neuropsychological assessments, and informants completed the Cambridge Behavioral Inventory-Revised (CBI-R). Patients were rated according to MCI criteria, including amnestic and non-amnestic subtypes, or as being cognitively intact. CBI-R ratings were evaluated with respect to MCI diagnosis and neuropsychological performance. RESULTS: Compared to cognitively intact individuals, informants rated patients with MCI as having significantly more change in overall functioning (p < 0.05) as well as in specific domains of memory and orientation (p < 0.01), everyday skills (p < 0.05), and motivation (p < 0.05), even after controlling for depressive symptom severity. In further analyses, the non-amnestic MCI subgroup only had more informant-rated mood changes compared to the amnestic subgroup. In relation to neuropsychological performance, informant ratings were related to poorer visual memory, verbal learning and memory, language, and psychomotor speed, with correlations ranging from -0.19 to -0.43 (p < 0.05). CONCLUSIONS: These findings indicate that informants are sensitive to subtle early cognitive change in individuals with MCI, and that their ratings are related to objectively measured neuropsychological performance. Thus, the CBI-R may be valuable in assisting early screening and intervention processes.

Sleep disturbance relates to neuropsychological functioning in late-life depression.

BACKGROUND: Sleep-wake disturbance in older people is a risk factor for depression onset and recurrence. The aim of this study was to determine if objective sleep-wake disturbance in late-life depression relates to neuropsychological functioning. METHODS: Forty-four older patients with a lifetime history of major depression and 22 control participants underwent psychiatric, medical and neuropsychological assessments. Participants completed self-report sleep measures, sleep diaries and wore wrist actigraphy for two weeks. Outcome measures included sleep latency, the number and duration of nocturnal awakenings and the overall sleep efficiency. RESULTS: Patients with depression had a greater duration of nocturnal awakenings and poorer sleep efficiency, in comparison to control participants. Sleep disturbance in patients was associated with greater depression severity and later ages of depression onset. It also related to poorer psychomotor speed, poorer verbal and visual learning, poorer semantic fluency as well as poorer performance on tests of executive functioning. These relationships largely remained significant after controlling for depression and estimated apnoea severity. LIMITATIONS: This sample had only mild levels of depression severity and results require replication in patients with moderate to severe depression. The inclusion of polysomnography and circadian markers would be useful to delineate the specific features of sleep-wake disturbance that are critical to cognitive performance. CONCLUSIONS: Sleep-wake disturbance in older patients with depression is related to neuropsychological functioning and to later ages of illness onset. This study suggests that common neurobiological changes may underpin these disease features, which may, in turn, warrant early identification and management.

Enhancing memory in late-life depression: the effects of a combined psychoeducation and cognitive training program.

OBJECTIVE: To evaluate the efficacy of a multifactorial cognitive training (CT) program for older people with a lifetime history of depressive disorder. METHODS: This was a single-blinded waitlist control design. The study was conducted in the Healthy Brain Ageing Clinic, a specialist outpatient clinic at the Brain & Mind Research Institute, Sydney, Australia. Forty-one participants (mean age = 64.8 years, sd = 8.5) with a lifetime history of major depression were included. They were stabilized on medication and had depressive symptoms in the normal to mild range. The intervention encompassed both psychoeducation and CT. Each component was 1-hour in duration and was delivered in a group format over a 10-week period. Psychoeducation was multifactorial, was delivered by health professionals and targeted cognitive strategies, as well depression, anxiety, sleep, vascular risk factors, diet and exercise. CT was computer-based and was conducted by Clinical Neuropsychologists. Baseline and follow-up neuropsychological assessments were conducted by Psychologists who were blinded to group allocation. The primary outcome was memory whilst secondary outcomes included other aspects of cognition and disability. RESULTS: CT was associated with significant improvements in visual and verbal memory corresponding to medium to large effect sizes. CONCLUSION: CT may be a viable secondary prevention technique for late-life depression, a group who are at risk of further cognitive decline and progression to dementia.

Can older "at risk" adults benefit from psychoeducation targeting healthy brain aging?

BACKGROUND: Multifactorial strategies that prevent or delay the onset or progress of cognitive decline and dementia are needed, and should include education regarding recognized risk factors. The current study sought to investigate whether older adults "at risk" of cognitive decline benefit from psychoeducation targeting healthy brain aging. METHODS: 65 participants (mean age 64.8 years, SD 9.6) with a lifetime history of major depression; vascular risk as evidenced by at least one vascular risk factor; and/or subjective or objective memory impairment were allocated to weekly psychoeducation sessions or a waitlist control group. The small group sessions were conducted over ten weeks by a team of medical and allied health professionals with expertise in late-life depression and cognition. Sessions focused on modifiable risk factors for cognitive decline including vascular risk, diet, exercise, depression, anxiety and sleep disturbance, as well as providing practical strategies for memory and cognition. Both the psychoeducation and waitlist group completed a 20-item knowledge test at baseline and follow-up. Participants in the psychoeducation group were asked to complete follow-up self-report satisfaction questionnaires. RESULTS: Repeated measures ANOVA showed a significant interaction effect depicting improvements in knowledge associated with psychoeducation, corresponding to an improvement of 15% from baseline. Satisfaction data additionally showed that 92.3% of participants rated the program as "good" to "excellent", and over 90% suggested they would recommend it to others. CONCLUSIONS: A group-based psychoeducation program targeting healthy brain aging is effective in improving knowledge. Additionally, it is acceptable and rated highly by participants.

Increased vulnerability to stress following opiate exposures: behavioral and autonomic correlates.

The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users.

Radical initiated polymerization in a bifunctional mixture via computer simulation.

Computer simulations are performed to study the polymerization behavior in a mixture of bifunctional groups such as olefins (A) and acrylates (B) in an effective solvent (a coarse description for vegetable oil derived macromonomers (VOMMs) in solution) on a cubic lattice. A set of interactions between these units and solvent (S) constituents and their relative concentrations (p(A), p(B), and p(S)) are considered. Samples are equilibrated with Metropolis algorithm to model the perceived behavior of VOMMs. The covalent bonding between monomeric units is then implemented via reaction pathways initiated by stochastic motion of free radicals (a very small fraction). The rate of reaction shows decay patterns with the time steps (t) with power laws (i.e., R(ab)alphat(-r), r congruent with 0.4-0.8), exponential decays (i.e., R(ab)alphae(-0.001t)), and their combination. Growth of A-B bonding is studied as a function of polymer concentration p=p(A)+p(B) for four different model systems appropriate for VOMMs. The data from the free radical initiated simulations are compared to the original simulations with homopolymerization. While most of the data are consistent with experimental observations, the variations are found to be model dependent.