Subjective perception of cognition is related to mood and not performance.

OBJECTIVE: Clinicians monitor cognitive effects of drugs primarily by asking patients to describe their side effects. We examined the relationship of subjective perception of cognition to mood and objective cognitive performance in healthy volunteers and neurological patients. METHODS: Three separate experiments used healthy adults treated with lamotrigine (LTG) and topiramate (TPM), adults with epilepsy on LTG or TPM, and patients with idiopathic Parkinson's disease. Correlations were calculated for change scores on and off drugs in the first two experiments and for the single assessment in Experiment 3. RESULTS: Across all three experiments, significant correlations were more frequent (chi(2)=259, P < or = 0.000) for mood versus subjective cognitive perception (59%) compared with subjective versus objective cognition (2%) and mood versus objective cognitive performance (2%). CONCLUSIONS: Subjective perception of cognitive effects is related more to mood than objective performance. Clinicians should be aware of this relationship when assessing patients' cognitive complaints.

Cognitive and behavioral effects of lamotrigine and topiramate in healthy volunteers.

BACKGROUND: The relative cognitive and behavioral effects of lamotrigine (LTG) and topiramate (TPM) are unclear. METHODS: The authors directly compared the cognitive and behavioral effects of LTG and TPM in 47 healthy adults using a double-blind, randomized crossover design with two 12-week treatment periods. During each treatment condition, subjects were titrated to receive either LTG or TPM at a target dose of 300 mg/day for each. Neuropsychological evaluation included 17 measures yielding 41 variables of cognitive function and subjective behavioral effects. Subjects were tested at the end of each antiepileptic drug (AED) treatment period and during two drug-free conditions (pretreatment baseline and 1 month following final AED withdrawal). RESULTS: Direct comparison of the two AEDs revealed significantly better performance on 33 (80%) variables for LTG, but none for TPM. Even after adjustment for blood levels, performance was better on 19 (46%) variables for LTG, but none for TPM. Differences spanned both objective cognitive and subjective behavioral measures. Comparison of TPM to the non-drug average revealed significantly better performance for non-drug average on 36 (88%) variables, but none for TPM. Comparison of LTG to non-drug average revealed better performance on 7 (17%) variables for non-drug average and 4 (10%) variables for LTG. CONCLUSIONS: Lamotrigine produces significantly fewer untoward cognitive and behavioral effects compared to topiramate (TPM) at the dosages, titrations, and timeframes employed in this study. The dosages employed may not have been equivalent in efficacy. Future studies are needed to delineate the cognitive and behavioral effects of TPM at lower dosages.

Proxy reliability: health-related quality of life (HRQoL) measures for people with disability.

OBJECTIVES: Research and surveillance activities sometimes require that proxy respondents provide key exposure or outcome information, especially for studies of people with disability (PWD). In this study, we compared the health-related quality of life (HRQoL) responses of index PWD to proxies. METHODS: Subjects were selected from nursing home, other assisted living residences, and from several clinic samples of PWD. Each index identified one or more proxy respondents. Computer-assisted interviews used a random order of measures. Proxy reliability was measured by intraclass correlation (ICC) and kappa statistics. HRQoL measures tested included the surveillance questions of the Behavioral Risk Factor Surveillance System (BRFSS), basic and instrumental activities of daily living (ADLs and IADLs), medical outcomes study short-form 36 and 12 (SF-36 and SF-12). RESULTS: A total of 131 index-proxy sets were completed. In general, agreement and reliability of proxy responses to the PWD tended to be best for relatives, with friends lower, and health care proxies lowest. For example, the ICC for the physical functioning scale of the SF-36 was 0.68 for relatives, 0.51 for friends, and 0.40 for healthcare proxies. There was a tendency for proxies to overestimate impairment and underestimate HRQoL. This pattern was reversed for measures of pain, which proxies consistently underestimated. The pattern among instruments, proxy types, and HRQoL domains was complex, and individual measures vary from these general results. CONCLUSIONS: We suggest caution when using proxy respondents for HRQoL, especially those measuring more subjective domains.

Depression measures in outcomes research.

OBJECTIVE: To review critically the measures used to screen for depression for disability outcomes research and to recommend measures and needed research. DATA SOURCES: Review of literature pertaining to the development, testing, and use of depression measures for outcomes research. STUDY SELECTION: English language literature from scientists from a broad range of disciplines and research settings, focusing mainly on the Brief Symptom Inventory and the Center for Epidemiology Study-Depression scale. DATA EXTRACTION: A literature review was completed through MEDLINE. Based on the review, instruments were selected according to their use among people with disability and the reliability and validity of the instrument. Two instruments were selected for a complete review, and 5 instruments were selected for a brief review. DATA SYNTHESIS: A critical review of measures that have been and may be used to measure depressive symptomatology among people with disability. CONCLUSIONS: Screening measures of depression are easy to administer and score. Almost all have low respondent burden and good face validity, thereby contributing to a high participation rate for most studies. Some problems exist with the application of these instruments to people with disability (ie, overlap of symptoms of depression and indicators of physical impairment).