Caregiver burden is increased in Parkinson's disease with mild cognitive impairment (PD-MCI).

BACKGROUND: There is limited evidence on caregiver outcomes associated with mild cognitive impairment in patients with Parkinson's disease (PD-MCI) and the coping strategies used by these caregivers. METHODS: To investigate this relationship, we examined levels of burden, depression, anxiety, coping strategies and positive aspects of caregiving in the informal caregivers of 96 PD patients. The PD patients were classified using MDS-Task Force Level II criteria as showing either normal cognition (PD-N; n = 51), PD-MCI (n = 30) or with dementia (PDD; n = 15). RESULTS: Mean Zarit Burden Interview (ZBI) score increased significantly between carers of PD-N (M = 13.39, SD = 12.22) compared to those of PD-MCI patients (M = 22.00, SD = 10.8), and between carers of PD-MCI and PDD patients (M = 29.33, SD = 9.59). Moreover, the proportion of carers showing clinically significant levels of burden (ZBI score ≥ 21) also increased as the patients' cognitive status declined (18% for PD-N; 60% for PD-MCI; and 80% for PDD) and was mirrored by an increasing amount of time spent providing care by the caregivers. Caregiver ZBI score was independent of patient neuropsychiatric symptoms, motor function, disease duration and time that caregivers spent caregiving. Caregiver use of different coping strategies increased with worsening cognition. However, we found only equivocal evidence that the use of problem-focused, emotion-focused and dysfunctional coping mediated the association between patient cognitive status and caregiver burden, because the inverse models that used caregiver burden as the mediator were also significant. CONCLUSIONS: The study highlights the impact of Parkinson's disease on those providing care when the patient's cognition is poor, including those with MCI. Caregiver well-being has important implications for caregiver support, nursing home placement and disease course.

A note on Cohen's overlapping proportions of normal distributions.

Social scientists are often interested in computing the proportion of overlap and nonoverlap between two normal distributions that are separated by some magnitude. In his popular book, Statistical Power Analysis for the Behavioral Sciences (1988, 2nd ed.), Jacob Cohen provided a table (Table 2.2.1) for determining such proportions from common values of separation. Unfortunately, Cohen's proportions are inconsistent with his explication of the popular index of effect size, d; and his proportions are underestimates of distributional overlap and overestimates of nonoverlap. The authors explain how Cohen derived his values and then provide a revised, corrected table of proportions that also match values presented elsewhere.

Toward a brighter future for psychology as an observation oriented science.

Serious criticisms of psychology's research practices and data analysis methods date back to at least the mid-1900s after the Galtonian school of thought had thoroughly triumphed over the Wundtian school. In the wake of Bem's (2011) recent, highly publicized study on psi phenomena in a prestigious journal, psychologists are again raising serious questions about their dominant research script. These concerns are echoed in the current paper, and Observation Oriented Modeling (OOM) is presented as an alternative approach toward data conceptualization and analysis for the social and life sciences. This approach is rooted in philosophical realism and an attitude toward data analysis centered around causality and common sense. Three example studies and accompanying data analyses are presented and discussed to demonstrate a number of OOM's advantages over current researcher practices.