Table 1.

Quantitative studies.

Study (author, year)	Purpose	Population/ sample	Research design	Intervention	Comparison	Outcome measures/ scales	Results
A'Campo et al. (2010) [24]	Formative evaluation of standardized psychosocial education program on quality of life	Caregivers n = 137 Parkinson's patients N = 151	Quasiexperimental design	8 weeks parallel program for Parkinson's patient and caregivers	None	MMSE, BELA-P-k, BELA-A-k, Bb, PDQ-39, SDS, Nfh, EQ-5D VAS, and Mood VAS	Mood, social, and emotional functioning and achievement capabilities improved significantly (P < 0.05). Depression did not improve
Carter et al. (2008) [1]	Understand motor and nonmotor symptom impact on caregiver strain	219 spouses, mean age: 66.7	Correlational design	None	None	FCI, CES-D, and UPDRS	Nonmotor symptoms cause ×2–4-fold increase in burden (P < 0.05)
D'Amelio et al. (2009) [23]	Determine predictors of caregiver burden	40 Parkinson patients and caregivers	Correlational design	None	None	CBI, HY, GDS, NPI, UPDRS-ME, and MMSE	Mental symptoms (P = 0.03) and Parkinson's severity of disease (<0.0001) correlated with caregiver distress
Kelly et al. (2012) [11]	Determine HRQoL in people with Parkinson's and its effect on caregiver strain	97 caregiver dyads 84% spouse (part of larger RCT study)	Cross-sectional correlational design	None	None	EQ-5D, PDQ-39, MCSI, 6MWT, and HY	Good HRQoL of PD patients correlated with low caregiver strain (rho 0.43, P < 0.001)
Leroi et al. (2012) [9]	Determine care burden in apathy and impulse control in Parkinson's	71 carer dyads	Cross-sectional correlational design	None	Control group	UPDRS, HY, BIS-11, AES-C, ZBI, LEDD, and HADS	Care burden is significant in impulse control (P = 0.002 and P = 0.004)
de Villiers et al. (2008) [17]	Investigate needs, roles, and experiences of primary caregivers in Parkinson's	126 participants 77% female 27% male	Descriptive quantitative	None	None	Developed scale: no name	Isolation (57%) Lack of time (47%) Felt powerless (45%) Felt stress (43%) Finance issues (40%) Physically drained (32%)
Rongve et al. (2010) [25]	Identify sleep disturbances in subtypes of dementia and explore clinical correlates	151 participants	Cross-sectional comparative design	None	Alzheimer's disease	NPI, Epsworth Sleepiness Scale, MSQ, MADRS, REM,	More sleep disturbances in PD (89%) versus Alzheimer's (64%). P = 0.008
Shim et al. (2011) [10]	Understand correlates of care mutuality in Parkinson's and Alzheimer's disease	152 dyads for Parkinson's and Alzheimer's 91 control (16% attrition in control)	Retrospective multilevel design	None	Alzheimer's disease and control	MSFCI, Lawton, IADL, and CESD	Longer caregiving years (P < 0.05), and increased IADL (P < 0.05) increase care mutuality; increased depression in carer decreased care-mutuality (P < 0.05)
Tokunaga et al. (2009) [19]	Investigate caregiver burden	54 pairs Parkinson's 48 pairs control age 65 and older	Unmatched case control design	None	Frail elderly	J-ZBI, CES-D, and DBD	Parkinson's caregiver spent less time caregiving for ADLs (2.78 hours) compared to frail elderly (11.2 hours) P < 0.01