Longitudinal differences in everyday preferences: Comparisons between people with cognitive impairment and their care partners

OBJECTIVES

Persons with progressive cognitive impairment (CI) increasingly rely on surrogate decision-makers for everyday activities. Yet, little is known about changes in everyday preferences over time or about concordance between persons with CI and their care partners regarding longitudinal changes.

METHODS

The sample included 48 dyads of persons with CI (Clinical Dementia Rating Scale score ≥0.5) and their care partners. The Preferences for Everyday Living Inventory was used to assess importance of preferences among persons with CI at baseline and follow-up (mean 486 days). Care partners separately completed concurrent proxy assessments. Mixed random and fixed effects longitudinal models were used to evaluate changes in ratings and concordance levels between persons with CI and care partners.

RESULTS

There were significant gender differences regarding importance ratings of "autonomous choice" and "social engagement" preferences over time: women with CI rated these preferences as more important across time as a whole. Higher levels of neuropsychiatric symptoms were associated with less importance of "social engagement" preferences across time as a whole for persons with CI and a more negative discrepancy between persons with CI and care partner proxy assessments as time went on.

CONCLUSION

This study yields new insights into predictors of longitudinal change in everyday preferences among persons with CI and their care partners. Although preferences were largely stable over time, there is increasing support for the relationship between differences in "social engagement" preferences and neuropsychiatric symptoms, which may have implications for monitoring and/or treatment in the context of cognitive impairment.

Differences in Assessment of Everyday Preferences Between People With Cognitive Impairment and Their Care Partners: The Role of Neuropsychiatric Symptoms

OBJECTIVE

As cognitive impairment progresses, people with dementia increasingly rely on surrogate decision-makers for everyday activities. Yet, little is known about concordance on everyday preferences between persons with cognitive impairment and their care partners.

METHODS

The sample included 69 dyads of persons with cognitive impairment (Clinical Dementia Rating Scale ≥0.5) and their care partners. We used the Preferences for Everyday Living Inventory (PELI) to assess preferences for activities and lifestyle choices among persons with cognitive impairment. The PELI was concurrently but separately administered to care partners, who answered as surrogate decision-makers. Factor analysis was used to ascertain factor structure of the PELI; reliability measures were computed within the sample. Paired sample t-tests were used to estimate differences in scores of corresponding PELI items for each factor. Multiple regression models were used to relate predictors, including neuropsychiatric symptoms, to agreement levels.

RESULTS

Four factors were identified from the PELI: autonomous choice, social engagement, personal growth, and keeping a routine. Significant participant-care partner discrepancy was found in "social engagement" preferences (e.g., regular contact with family, meeting new people, volunteering). Geriatric Depression Scale-15 score and care partner sex were significantly associated with participant-care partner discrepancies in "social engagement" preferences.

CONCLUSION

This study yields new insights regarding the most important preferences for persons with cognitive impairment and clarifies a path to optimizing surrogate decision-making around everyday preferences by highlighting areas of apparent disagreement and identifying potential predictors of discrepancy.

Abnormal neurotransmission in mice lacking synaptic vesicle protein 2A (SV2A)

Synaptic vesicle protein 2 (SV2) is a membrane glycoprotein common to all synaptic and endocrine vesicles. Unlike many proteins involved in synaptic exocytosis, SV2 has no homolog in yeast, indicating that it performs a function unique to secretion in higher eukaryotes. Although the structure and protein interactions of SV2 suggest multiple possible functions, its role in synaptic events remains unknown. To explore the function of SV2 in an in vivo context, we generated mice that do not express the primary SV2 isoform, SV2A, by using targeted gene disruption. Animals homozygous for the SV2A gene disruption appear normal at birth. However, they fail to grow, experience severe seizures, and die within 3 weeks, suggesting multiple neural and endocrine deficits. Electrophysiological studies of spontaneous inhibitory neurotransmission in the CA3 region of the hippocampus revealed that loss of SV2A leads to a reduction in action potential-dependent gamma-aminobutyric acid (GABA)ergic neurotransmission. In contrast, action potential-independent neurotransmission was normal. Analyses of synapse ultrastructure suggest that altered neurotransmission is not caused by changes in synapse density or morphology. These findings demonstrate that SV2A is an essential protein and implicate it in the control of exocytosis.

The methylglutamate, SYM 2081, is a potent and highly selective agonist at kainate receptors

The methylglutamate analog (2S,4R)-4-methylglutamate (SYM 2081) has been shown to potently displace high affinity [3H]kainate binding to cortical tissue and to recombinant kainate receptors, and to evoke rapidly desensitizing responses in electrophysiological recordings. We have used two electrode voltage clamp recordings to compare the potency and efficacy of SYM 2081 with other alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA)/kainate receptor agonists at homomeric kainate and AMPA receptors expressed in Xenopus oocytes. In the presence of concanavalin A to reduce agonist induced desensitization at kainate receptors, SYM 2081 was a potent agonist at homomeric kainate receptors composed of the GluR5 and GluR6 subunit, with an EC50 of 0.12 +/- 0.02 and 0.23 +/- 0.01 microM, respectively. SYM 2081 was highly selective for kainate receptors, the EC50 for activation of AMPA receptors composed of the GluR1 and GluR3 subunits was 132 +/- 44 and 453 +/- 57 microM, respectively. Other methylglutamate analogs were tested for kainate receptor agonist activity. Methylglutamate compounds with the methyl group at the 2 or 3 position of glutamate were inactive indicating that positioning of the methyl group at the 4 position was essential for agonist activity. Of the four stereoisomers of 4-methylglutamate, SYM 2081 (2S,4R) was the most potent agonist. The (2R,4R) isomer was estimated to be 20-fold and the (2S,4S)-isomer approximately 1000-fold less potent than SYM 2081. These results indicate that SYM 2081 is a potent and selective agonist at kainate receptors, and thus will be a useful ligand for evaluating the role of kainate receptors in central nervous system function and disease.