Nonpharmacological enhancement of cognitive function in Parkinson's disease: a systematic review.

Cognitive decline and dementia are frequent in patients with Parkinson's disease (PD). The evidence for nonpharmacological therapies in Alzheimer's disease and other dementias has been studied systematically, but the evidence is unclear for their efficacy in cognition and dementia in PD. An international collaboration produced a comprehensive, systematic review of the effectiveness and of nonpharmacological and noninvasive therapies in cognitively intact, cognitively impaired, and PD dementia groups. The interventions included cognitive rehabilitation, physical rehabilitation, exercise, and brain stimulation techniques but excluded invasive treatments, such as surgery and deep brain stimulation. The potential biases and evidence levels for controlled trials (CTs) were analyzed based on Cochrane and National Institute for Health and Clinical Excellence criteria. After exclusions, 18 studies were reviewed, including 5 studies of cognitive training, 4 of exercise and physical therapies, 4 of combined cognitive and physical interventions, and 5 of brain stimulation techniques. The methodology, study populations, interventions, outcomes, control groups, analyses, results, limitations, biases, and evidence levels of all reviewed studies were described. There were 9 CTs, including 6 randomized CTs (RCTs). Although 5 trials showed positive results, only 1 study of cognitive training achieved evidence grading of 1+ with a low risk of bias. There were no studies on PD dementia. Current research on nonpharmacological therapies for cognitive dysfunction and dementia in PD is very limited in quantity and quality. There is an urgent need for rigorous RCTs of nonpharmacological treatments for cognitive impairment and dementia in PD.

Apolipoprotein E ε4 does not affect cognitive performance in patients with Parkinson's disease.

INTRODUCTION: Cognitive impairment is a common and disabling non-motor symptom in Parkinson's disease (PD). The apolipoprotein E (APOE) allele ε4 is a known risk factor for Alzheimer's disease and has also been suggested to be a risk factor for dementia in PD and even a predictor of impairment in certain cognitive domains. METHODS: A total of 447 PD patients (PD patients without cognitive impairment: n = 187; PD patients with mild cognitive impairment: n = 188; PD patients with dementia: n = 72) were included from an ongoing observational German multicenter cohort study (LANDSCAPE study). All patients underwent an extensive neuropsychological test battery, including assessments of memory, visuospatial functioning, attention, language, and executive function. APOE genotype was determined by an allelic discrimination assay. Linear regression analysis was used to explore the associations between APOE-ε4 and cognitive performance. RESULTS: The APOE-ε4 allele was not associated with a diagnosis of cognitive impairment in PD (PD with mild cognitive impairment and PD with dementia) or with deficits in specific neuropsychological domains in our study cohort. CONCLUSION: Our data question the relevance of the APOE-ε4 allele as a predictor of cognitive impairment in PD.

Effects of cognitive training with additional physical activity compared to pure cognitive training in healthy older adults.

INTRODUCTION: Cognitive training (CT) has been reported to improve cognition in older adults. Its combination with protective factors such as physical activity (CPT) has rarely been studied, but it has been suggested that CPT might show stronger effects than pure CT. MATERIALS AND METHODS: Healthy older adults (aged 50-85 years) were trained with CPT (n=15) or CT (n=15). Interventions were conducted in 90-minute sessions twice weekly for 6.5 weeks. Cognitive functions were assessed before and immediately after the interventions, and at 1-year follow-up. RESULTS: The main finding was an interaction effect on attention, with comparable gains from CPT and CT from pre- to post-test, but stronger effects of CPT to follow-up (P=0.02). Significant effects were found in subjects in terms of cognitive state (P=0.02), letter verbal fluency (P=0.00), and immediate (P=0.00) and delayed (P=0.01) verbal memory. Post hoc analyses indicated that these latter domains were affected differentially by CPT and CT. No significant between-subject effects were found. CONCLUSION: Our results suggest that CPT might lead to stronger long-term effects on attention. However, as the difference between CT and CPT was only evident at follow-up, these effects cannot be interpreted as a direct consequence of CPT; they may have been related to sustained physical activity after the training. Other domains were improved by both interventions, but no typical pattern could be identified. Possible underlying mechanisms are discussed, and directions for future research are suggested.

Sex differences in cognitive training effects of patients with amnestic mild cognitive impairment.

Cognitive training has been shown to be effective in improving cognitive functions in patients with Mild Cognitive Impairment (MCI). However, data on factors that may influence training gains including sociodemographic variables such as sex or age is rare. In this study, the impact of sex on cognitive training effects was examined in N = 32 age- and education-matched female (n = 16) and male (n = 16) amnestic MCI patients (total sample: age M = 74.97, SD = 5.21; education M = 13.50, SD = 3.11). Patients participated in a six-week multidomain cognitive training program including 12 sessions each 90 min twice weekly in mixed groups with both women and men. Various cognitive domains were assessed before and after the intervention. Despite comparable baseline performance in women and men, we found significant interaction effects Time × Sex in immediate (p = .04) and delayed verbal episodic memory (p= .045) as well as in working memory (p = .042) favoring the female MCI patients. In contrast, the overall analyses with the total sample did not reveal any significant within-subject effects Time. In conclusion, our results give preliminary evidence for stronger cognitive training improvements of female compared to male MCI patients. More generally, they emphasize the importance of sex-sensitive evaluations of cognitive training effects. Possible underlying mechanisms of the found sex differences are discussed and directions for future research are given.

Effects of cognitive training in Parkinson's disease: a randomized controlled trial.

BACKGROUND: In Parkinson's Disease (PD), cognitive dysfunctions which can reduce patients' quality of life occur frequently. Data on non-pharmacological intervention effects on cognitive functions in patients with PD are rare. The aim of this study was to examine the effects of different cognitive group trainings (structured vs. unstructured) on cognition, depression, and quality of life in non-demented PD patients. METHODS: In this randomized controlled trial, 65 non-demented patients with PD according to UK Brain Bank criteria (Hoehn & Yahr I-III) were allocated to one of two cognitive multi-component treatments ("NEUROvitalis", a structured training, or the unstructured training "Mentally fit" with randomly assembled cognitive tasks, each including 12 group-sessions à 90 min over 6 weeks) or a waiting list control group (CG). A neuropsychological test battery was performed before and after the training. RESULTS: Compared to the CG, patients from the "NEUROvitalis" group improved in short-term memory (word list learning "Memo": p < .01) and working memory (digit span reverse from "DemTect": p < .05), whereas depression scores where reduced in the "Mentally fit" group (Beck Depression Inventory-II: p < .05). The "NEUROvitalis" group improved significantly more in working memory than the "Mentally fit" group (DemTect: p < .05). DISCUSSION: Cognitive and affective functions can be improved by cognitive trainings in PD patients. Specific effects (e.g. on memory and working memory versus depression) seem to be dependent on the type of training. Further research is needed to define long-term effects and the efficacy in PD patients with different extent of cognitive and neuropsychiatric symptoms.