Cognition in type 2 diabetes: Association with vascular risk factors, complications of diabetes and depression

Background

The role of variables like duration of diabetes, diabetic control and microvascular complications in the causation of cognitive decline in patients with type 2 diabetes is not well studied. The contribution of hypertension to the cognitive decline in nondemented diabetic patients is unclear.

Aims:

We wanted to see if cognition in patients with type 2 diabetes is associated with the duration of diabetes, control of diabetes, complications of diabetes, vascular risk factors, or depression. We also looked at association of noncompliance with cognition, and depression.

Settings and Design:

We recruited ambulant patients with type 2 diabetes who are 55 years or more in age from the weekly diabetic clinic. We excluded patients with past history of stroke.

Methods and Material:

We selected the time taken for the Trial A test, delayed recall on ten-word list from Consortium to Establish a Registry for Alzheimer''s Disease (CERAD), Rowland Universal Dementia Assessment Scale (RUDAS) and Centre for Epidemiologic Studies Depression scale (CES-D) screening instrument to assess these patients.

Statistical Analysis Used:

We utilized mean, standard deviation, Chi-square test and Pearson''s correlation for statistical analysis. We considered P < 0.05 to be significant.

Results:

RUDAS scores inversely correlated (r = −0.360) with CES-D scores (P = 0.002). Scores of the screening instrument for depression, the CES-D was associated with the duration of diabetes mellitus (P = 0.018), fasting blood glucose (P = 0.029) as well as with 2-hour post prandial blood glucose (P = 0.017).

Conclusions:

There is correlation between depression and global cognitive score. Depression seems to be associated with duration of diabetes and control of diabetes.     

Identifying risk for dementia across populations: A study on the prevalence of dementia in tribal elderly population of Himalayan region in Northern India

Introduction:

Studies have suggested that dementia is differentially distributed across populations with a lower prevalence in developing regions than the developed ones. A comparison in the prevalence of dementia across populations may provide an insight into its risk factors. Keeping this in view, a study was planned to evaluate the prevalence of dementia in tribal elderly population.

Materials and Methods:

A cross-sectional comprehensive two-phase survey of all residents aged 60 years and older was conducted. Phase one involved screening of all individuals aged 60 and above with the help of a cognitive screen specifically developed for the tribal population. Phase two involved clinical examination of individuals who were suspected of dementia as per the developed cognitive screening test.

Results:

The results revealed that no individual above 60 years of age in the studied population was diagnosed as a case of dementia. Thereby, pointing out at some unknown factors, which are responsible for prevention of dementia.

Discussion:

The differences between the prevalence rate in this study and other studies in India appear to be a function of a valid regional difference. Environmental, phenotypic and genetic factors may contribute to regional and racial variations in dementia. Societies living in isolated hilly and tribal areas seem less predisposed to dementia, particularly age related neurodegenerative and vascular dementia, which are the most common causes for dementia in elderly. This may be because some environmental risk factors are much less prevalent in these settings.Key Words: Dementia, populations, risk, tribal     

Neuropsychological markers of mild cognitive impairment: A clinic based study from urban India

Background:

Mild cognitive impairment (MCI) is a transitional stage between normal aging and dementia. Persons with MCI are at higher risk to develop dementia. Identifying MCI from normal aging has become a priority area of research. Neuropsychological assessment could help to identify these high risk individuals.

Objective:

To examine clinical utility and diagnostic accuracy of neuropsychological measures in identifying MCI.

Materials and Methods:

This is a cross-sectional study of 42 participants (22 patients with MCI and 20 normal controls [NC]) between the age of 60 and 80 years. All participants were screened for dementia and later a detailed neuropsychological assessment was carried out.

Results:

Persons with MCI performed significantly poorer than NC on word list (immediate and delayed recall), story recall test, stick construction delayed recall, fluency and Go/No-Go test. Measures of episodic memory especially word list delayed recall had the highest discriminating power compared with measures of semantic memory and executive functioning.

Conclusion:

Word list learning with delayed recall component is a possible candidate for detecting MCI from normal aging.     

A cross-sectional study on thyroid status in North Indian elderly outpatients with dementia

Background:

Several population based studies have demonstrated an association between hypo-or hyperthyroidism and dementia in last two decades. As a consequence, thyroid stimulating hormone has become part of the screening laboratory test for dementia.

Aim:

The aim of the present study was to evaluate the association between thyroid function and Alzheimer''s disease (AD) and vascular dementia (VaD) and to determine the risk of AD and VaD in clinically euthyroid patients.

Materials and Methods:

A cross-sectional hospital based study was carried out in subjects diagnosed with AD/VaD and were assessed for thyroid status as routine screening test.

Results:

Free T3, free T4 and TSH were studied in 114 AD patients (mean age: 65 years), 35 VaD patients (mean age: 62 years) and 105 control subjects (mean age: 62 years). In AD group, TSH levels were significantly lower than controls (P = 0.00) and for each unit increase in TSH level, the odds of having dementia decreased by 37.1%. No such relation was seen in VaD.

Conclusion:

The results suggest a consistent association of subclinical hyperthyroidism and AD.     

Prevalence and risk factors of carotid intima-media thickness in asymptomatic individual subjects in a tertiary care center in India

Background:

Carotid intima-media thickness (IMT) is increasingly identified as a marker of atherosclerosis and increased risk of cerebrovascular disease.

Aim:

We aimed to investigate the prevalence of carotid IMT in asymptomatic Indian individuals, more than 40 years of age, and correlate it with other risk factors for cerebrovascular ischemia.

Materials and Methods:

Individuals attending outpatient services of Nizam''s Institute of Medical Sciences, who were asymptomatic for cerebrovascular ischemia underwent detailed history and carotid Doppler examination. IMT on mid common carotid artery (CCA) was measured. All subjects’ blood was taken for biochemical estimation of fasting blood sugar and total cholesterol levels.

Results:

Out of 1,392 subjects, 571 (41%) had abnormal IMT and 821 (59%) had normal IMT. On comparison of the two groups, the factors significantly associated with abnormal IMT were mean older age (59 vs 50.7 years; P < 0.0001) and higher prevalence of hypertension (257 (45%) vs 236 (28.7%); P < 0.0001), diabetes (159 (27.8%) vs 139 (16.9%); P < 0.0001), and hypercholesterolemia (124 (21.7%) vs113 (13.7%); P = 0.0001). After adjustment with multiple logistic regression, significant predictors were age (odds 3.2; 95% confidence interval (CI) 2.5-4.1), male gender (odds 1.5; 95% CI 1.1-1.9), hypercholesterolemia (odds 1.5; 95% CI 1.1-2.0), hypertension (odds 1.4; 95% CI 1.1-1.8), and diabetes (odds 1.3; 95% CI 1.0-1.7).

Conclusion:

We found age, sex, hypertension, diabetes, and hypercholesterolemia to be independent risk factor for abnormal IMT in asymptomatic subjects over 40 years of age.     

Sleeping over a sleep disorder - Awareness of obstructive sleep apnoea as a modifiable risk factor for hypertension and stroke: A survey among health care professionals and medical students

Background:

Obstructive sleep apnoea (OSA) syndrome is an established and modifiable but under recognized risk factor for common disorders like stroke and hypertension.

Objective:

To assess awareness level of health care practitioners and medical students about OSA as a risk factor for stroke and hypertension.

Methods:

Questionnaire based survey with multiple response type and fill in the blanks type questions. The data was compiled and analyzed using SPSS version 19.

Results:

180 participants completed the survey questionnaire. Only 24 (13.3%) identified OSA as a reversible risk factor for ischemic stroke. 11 (6%) participants only could answer OSA as an identified risk factor for hypertension as per Seventh Joint National Committee report.

Conclusion:

This study reveals dismal level of awareness, among health professionals and medical students, about OSA being an established and modifiable risk factor for hypertension and ischemic stroke.     

The profile of behavioral and psychological symptoms in vascular cognitive impairment with and without dementia

Objective:

The objective of this study was to compare the occurrence and severity of behavioral and psychological symptoms of dementia (BPSD) between vascular dementia (VaD) and vascular cognitive impairment-no dementia (VCI-ND).

Materials and Methods:

Consecutive patients presenting with cognitive impairment at least 3 months after an ischemic stroke and with a Hachinski Ischemic Score ≥4 were included. VaD was diagnosed as per National Institute of Neurological Disorders and Stroke – Association Internationale pour la Recherche et l’Enseignement en Neurosciences criteria for probable VaD and VCI-ND on the lines of the Canadian study of health and aging. The severity of cognitive impairment and the behavioral/psychological symptoms were studied by means of the clinical dementia rating scale and the neuropsychiatric inventory (NPI) respectively.

Results:

All patients with VaD and 89% of those with VCI-ND had at least one BPSD. The mean no. of symptoms per patient and the total NPI scores were higher in VaD than in VCI-ND. Apathy and night-time behavior disturbances were significantly more common and severe in VaD.

Conclusions:

BPSD are very common both in VCI-ND and in VaD. The profile of BPSD is similar in both groups, albeit more severe in VaD. The net burden of BPSD is higher in VaD as compared to VCI-ND.Key Words: Behavioral and psychological symptoms, neuropsychiatric inventory, vascular cognitive impairment, vascular cognitive impairment-no dementia, vascular dementia     

Vitamin D as a marker of cognitive decline in elderly Indian population

Objectives:

Very few studies in India have addressed the role of vitamin D in cognitive function. The present study was conducted to assess the serum levels of 25-hydroxyvitamin D (25(OH)D) and its association with markers of cognitive impairment and homocysteine levels in the elderly Indian population.

Materials and Methods:

The study population consisted of patients with dementia (Group A, n = 32), mild cognitive impairment (MCI; Group B, n = 24), and elderly age-matched controls (Group C, n = 30). Measurement of serum levels of 25(OH)D and total homocysteine were done.

Results:

Significant decreased concentration of 25(OH)D and increased concentration of homocysteine was observed. Association of serum levels of vitamin D with markers of cognitive decline as well as serum homocysteine levels was observed in patients with dementia and MCI when compared to controls.

Conclusion:

Correlation of vitamin D with markers of cognitive decline and homocysteine opens a new door for early diagnosis of cognitive impairment.     

Neuropsychiatric profiles in patients with Alzheimer's disease and vascular dementia

Background/Aims:

The aim of the following study is to compare the behavioral and psychological symptoms of dementia (BPSD) in patients of Alzheimer disease (AD) and vascular dementia (VaD).

Materials and Methods:

We used National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer''s Disease and Related Disorders Association criteria for diagnosing AD and National Institute of Neurological Disorders and Stroke-Association International pour la Recherche et l’Enseignement en Neurosciences Criteria for diagnosing VaD. VaD cohort was further subcategorized into small vessel and large vessel disease. The severity of cognitive impairment and the BPSD were studied by means of the Clinical Dementia Rating Scale (CDR) and the Neuropsychiatric Inventory respectively.

Results:

We studied 50 AD and 50 VaD patients of whom 38 were small vessels and 12 were large vessels VaD. The severity of dementia was comparable in both groups. The agitation/aggression, depression/dysphoria, anxiety, apathy/indifference, irritability, aberrant motor behavior, appetite and eating behavior and night-time behaviors occurred significantly more frequently in patients with VaD than AD. We found a weak positive correlation between the CDR score and the number of neuropsychiatric symptoms per patient in both cohorts. Elation/euphoria, agitation/aggression was significantly more frequent in patients with large vessel in comparison to small vessel VaD.

Conclusions:

BPSD are common in both types of dementia and they are more severe in VaD than AD when the groups have similar levels of cognitive impairment.     

Effect of antihypertensive therapy on cognitive functions of patients with hypertension

Objectives:

Hypertension is known to be associated with cognitive decline. Many studies revealed that control of hypertension with antihypertensive therapy controls the cognitive decline associated with hypertension. While there are reports that suggest that antihypertensive drugs do not provide protection from cognitive decline, the present study is designed to evaluate the cognitive status of patients recently diagnosed as hypertensive and effect of 3 month long antihypertensive therapy on cognitive functions.

Materials and Methods:

A predesigned pretested questionnaire was used to collect the information. The PGI memory scale (PGIMS) was employed to assess memory function of patients. Baseline memory functions were evaluated before starting the treatment with antihypertensive and compared with the cognitive function scores of healthy volunteers. After the 3 months of treatment, cognitive functions were evaluated again by the same scale. The unpaired t-test was used to compare the cognitive functions between case and control and the paired t-test was used to compare pre- and post-treatment score.

Results:

This study revealed that mean scores of six subtests of cognitive functions were less in cases as compared to subjects in comparison group. After 3 months of antihypertensive therapy, scores of five sub-tests were found to be increased. Among these five subtests, four were those which were found declined at the baseline.

Conclusion:

This suggests that antihypertensive therapy given for 3 months improved the score of those cognitive function tests in which hypertensive patients perform poorly during recruitment and there was no deterioration of any test after 3 months of antihypertensive therapy.     

Qualitative aspects of learning, recall, and recognition in dementia

Objective:

To determine whether learning and serial position effect (SPE) differs qualitatively and quantitatively among different types of dementia and between dementia patients and controls; we also wished to find out whether interference affects it.

Materials and Methods:

We administered the Malayalam version of the Rey Auditory Verbal Learning Test (RAVLT) to 30 cognitively unimpaired controls and 80 dementia patients [30 with Alzheimer''s disease (AD), 30 with vascular dementia (VaD), and 20 with frontotemporal dementia (FTD)] with mild severity on the Clinical Dementia Rating Scale.

Results:

All groups were comparable on education and age, except the FTD group, who were younger. Qualitatively, the learning pattern and SPE (with primacy and recency being superior to intermediate) was retained in the AD, VaD, and control groups. On SPE in free recall, recency was superior to intermediate in the FTD group (P < 0.01 using Bonferroni correction). On recognition, the AD and VaD groups had more misses (P < 0.01), while the FTD group had more false positives (P < 0.01).

Conclusion:

Quantitative learning is affected by dementia. The pattern of qualitative learning remains unaltered in dementia in the early stages.     

Issues in evaluation of cognition in the elderly in developing countries

Background:

Developing regions of the world host the majority of elderly subjects who are at risk for dementia. Reliable epidemiological data from these countries is invaluable in tackling this global problem. Scarcity of such data in literature is largely attributable to problems that are unique to developing communities worldwide.

Objective:

To classify and describe the problems that interfere with the collection of reliable epidemiological data on cognitive impairment in the elderly in developing communities, and to suggest practical solutions for some of them.

Methods:

Inferring from the experiences of a large, ongoing, population-based study on the cognitive impairments in the elderly in South India and from the review of literature.

Conclusion:

A fatalistic attitude regarding aging in the communities, significant heterogeneity in educational abilities and activities of daily living, high illiteracy among rural subjects, and lack of an organized health care system and updated demographic figures are some of the major factors that contribute to technical, namely, methodology-related problems and practical, namely, subject-related problems in such epidemiological studies.     

Relationship between activities of daily living and cognitive ability in a sample of older adults with heterogeneous educational level

Introduction:

A number of studies have shown the impact of cognitive abilities on instrumental activities of daily living, in particular executive functions. Nevertheless, it is not clear to what extent these results can be generalized, given that most samples studied have not included people with a low educational level.

Objectives:

The current study aims to investigate the association between cognitive abilities and activities of daily living in older adults — with and without dementia — from a middle-income country.

Sample:

The sample consisted of 48 healthy older adults and 29 people with dementia, who were evaluated in an Outpatient Care Unit in a University Reference Center in Rio de Janeiro.

Results:

Regression analyses indicated that the best predictors for activities of daily living were performance in immediate verbal memory in the case of controls and in a categorical fluency task in the patient group. The educational level itself was not a significant predictor of functional ability in either sample, but showed moderate correlation with the predictors.

Conclusions:

These results suggest that educational level may be a mediating factor in the association of cognitive variables and activities of daily living, and indicate a potential dissociation in terms of predictors according to the diagnostic status, pointing to relevant treatment directions.     

Improvement of Screening Accuracy of Mini-Mental State Examination for Mild Cognitive Impairment and Non-Alzheimer's Disease Dementia by Supplementation of Verbal Fluency Performance

Objective

This study aimed to investigate whether the supplementation of Verbal Fluency: Animal category test (VF) performance can improve the screening ability of Mini-Mental State Examination (MMSE) for mild cognitive impairment (MCI), dementia and their major subtypes.

Methods

Six hundred fifty-five cognitively normal (CN), 366 MCI [282 amnestic MCI (aMCI); 84 non-amnestic MCI (naMCI)] and 494 dementia [346 Alzheimer''s disease (AD); and 148 non-Alzheimer''s disease dementia (NAD)] individuals living in the community were included (all aged 50 years and older) in the study.

Results

The VF-supplemented MMSE (MMSE+VF) score had a significantly better screening ability for MCI, dementia and overall cognitive impairment (MCI plus dementia) than the MMSE raw score alone. MMSE+VF showed a significantly better ability than MMSE for both MCI subtypes, i.e., aMCI and naMCI. In the case of dementia subtypes, MMSE+VF was better than the MMSE alone for NAD screening, but not for AD screening.

Conclusion

The results support the usefulness of VF-supplementation to improve the screening performance of MMSE for MCI and NAD.     

Visual recognition memory differentiates dementia with Lewy bodies and Parkinson's disease dementia

Objective

To compare cognitive impairments in dementia with Lewy bodies (DLB) and Parkinson''s disease dementia (PDD), to discriminate between the two entities.

Methods

10 DLB and 12 PDD consecutive patients performed a neuropsychological battery designed to assess several cognitive domains: verbal and visual memory (Delayed Matching to Sample (DMS)‐48), language, gnosia, praxia and executive functions.

Results

DLB patients had poorer performances in orientation (p<0.05), Trail Making Test A (p<0.05) and reading of names of colours in the Stroop Test (p<0.05). Their scores were also lower in the visual object recognition memory test (DMS‐48), in both immediate (p<0.05) and delayed recognition (p<0.05). No differences were observed in the other tests.

Conclusion

Despite global similarities in cognitive performances between DLB and PDD patients, we observed important differences: in particular, DMS‐48, a test of visual object recognition memory and visual storage capacity, was poorer in DLB patients.Parkinson''s disease dementia (PDD) and dementia with Lewy bodies (DLB) share some common clinical features, such as extrapyramidal symptoms and neuropsychological impairment.^1,2,3 In practice, consensus guidelines recommend an arbitrary distinction between the two disorders based on a temporal sequence of 1 year between the presentation of extrapyramidal motor symptoms and the manifestation of dementia: PDD is diagnosed if dementia occurs belatedly in the context of well established Parkinson''s disease; DLB is diagnosed when motor and cognitive signs appear during the first year of evolution.⁴ A key question is whether this is a meaningful distinction between the two different clinical entities.Subtle clinical distinction in terms of cognitive pattern could prove useful for clinicians.In this study, we compared cognitive performances in a group of patients with a clinical diagnosis of “probable” DLB with those of PDD patients. As the clinical symptoms overlap, our aim was to determine possible differences in the cognitive abilities between DLB and PDD.     

Correlation of intracranial atherosclerosis with carotid stenosis in ischemic stroke patients

Introduction:

Carotid stenosis is a major risk factor for ischemic stroke. However, the effect of carotid stenosis on the site of stroke is still under investigation.

Aims:

This study aimed to elucidate how the presence of carotid stenosis influenced the pattern of stroke and also how it interacted with other risk factors for stroke.

Materials and Methods:

Thirty-eight patients with ischemic stroke were included in this study and were investigated with carotid artery Doppler and magnetic resonance angiography for carotid stenosis and intracranial stenosis in the circle of Willis, respectively. Other known risk factors of stroke were also studied in and compared between the subgroups with and without carotid stenosis.

Results:

In patients without carotid stenosis, anterior cerebral artery was the commonest site of stenosis. In patients with carotid stenosis, middle cerebral artery was the commonest site of stenosis. Overall, middle cerebral artery was the commonest territory of stroke. Patients with hypertension, diabetes and history of smoking had preferential stenosis of the anterior cerebral artery.     

Role of vitamin B12, folate, and thyroid stimulating hormone in dementia: A hospital-based study in north Indian population

Background:

Vitamin B₁₂ and folate represent modifiable risk factors for dementia. They may increase the risk of Alzheimer′s dementia (AD) and vascular dementia (VaD) as their deficiency can increase the homocysteine level due to slowed methylation reaction. Homocysteine has a neurotoxic effect that could lead to neurologic disturbances. Hence, it is important to explore the status of serum B₁₂ and folate in AD and VaD to evolve the treatment strategies for the same.

Objectives:

A retrospective study was conducted to assess the levels of vitamin B₁₂, folate, and thyroid stimulating hormone (TSH) in serum and the relationship of these factors, including age and sex to cognitive decline in VaD, AD, and dementia due to other causes (DOC).

Materials and Methods:

Serum vitamin B₁₂, folate, TSH, and total cholesterol were studied in 32 AD patients (mean age: 65 years), 12 VaD patients (mean age: 61 years), 83 DOC (mean age: 65 years), and 127 control subjects (mean age: 49 years). Results: In AD, VaD, and DOC, the levels of vitamin B₁₂ and folate were significantly lower (P < 0.002; 0.026; 0.002 for vitamin B₁₂ and P < 0.000 in all the 3 groups for folate) as compared with the controls. Similarly, TSH levels were significantly lower in AD and DOC (P < 0.008; 0.038) as compared with the controls.

Conclusion:

Vitamin B₁₂ and folate were significantly low in both AD and VaD patients. Hence, B vitamin supplementation should be considered as possible targets for the therapeutic intervention in dementia.     

Clinical characteristics and long-term outcome of surgery for hypothalamic hamartoma in children with refractory epilepsy

Context:

Hypothalamic hamartomas (HH) are ectopic masses of neuronal and glial tissue most commonly presenting with medically refractory gelastic seizures with evolution to other seizure types. They are also associated with cognitive and behavioral problems to varying extent. Surgery has been found to improve quality of life in more than 50% of patients.

Aim:

To evaluate the clinical characteristics and long-term outcome of surgery in children with HH and refractory epilepsy.

Materials and Methods:

A retrospective analysis of presurgical, surgical, and postsurgical data of six children who underwent surgery for HH and had at least 3 years follow-up was performed.

Results:

Six children (male: female = 5:1) aged 3-16 years (at the time of surgery) underwent surgical resection of HH for refractory epilepsy. At last follow-up (range 3-9 years), three children were in Engel''s class I, two in Class II, and one in class III outcome. Significant improvement in behavior, quality of life was noted in four children; while the change in intelligence quotient (IQ) was marginal.

Conclusions:

Medically refractory epilepsy associated with behavioral and cognitive dysfunction is the most common presentation of HH. Open surgical resection is safe with favorable outcome of epilepsy in 50% with significant improvement in behavior and marginal change in cognitive functions.     

Effect of Cardiac Function on Cognition and Brain Structural Changes in Dementia

Background and Purpose

Cardiovascular risk factors are considered to also be risk factors for dementia. Recent studies have shown that the prevalence of cognitive dysfunction is high in patients with cardiac diseases. However, few studies have investigated the influence of cardiac function on cognition and brain structural changes in dementia. The aims of this study were to determine the relationship between cardiac and cognitive function, and to characterize any structural changes in the brain that could be caused by cardiac function in patients with dementia.

Methods

Dementia patients (n=93) were recruited prospectively with checking for the presence of vascular risk factors such as hypertension. Cognitive function was measured by the Mini-Mental State Examination, modified Mini-Mental State test, and Korean version of the Dementia Rating Scale. Brain magnetic resonance imaging was conducted to evaluate the cerebral white-matter changes (WMC), ventricular dilation, and cortical and hippocampal atrophy. Cardiac function was evaluated using two-dimensional echocardiography. We divided the patients into two groups according to the presence (+) or absence (-) of WMC.

Results

In the entire cohort, the size of the left atrium (LA) was positively correlated with the degree of WMC, irrespective of age (p<0.05). The LA was larger in the WMC (+) group (n=42) than in the WMC (-) group. General cognitive function was significantly lower in the WMC (+) group than in the WMC (-) group. Subjects with an enlarged LA tended to exhibit lower cognitive function and more-severe cerebral WMC.

Conclusions

Cardiac dysfunction represented by LA enlargement could be related to cognitive decline and WMC of the brain resulting from impairment of the cerebral hemodynamic process in dementia.     

Acupuncture improves cognitive function A systematic review

BACKGROUND: Acupuncture has been used as a treatment for cognitive impairment. OBJECTIVE: This review assesses clinical evidence for or against acupuncture as a treatment for cognitive impairment. This review also discusses the proposed mechanism(s) that could link acupuncture to improved cognitive function. METHODS: We searched the literature using PolyUone search from its inception to January 2013, with full text available and language limited to English. Levels of evidence were examined using Oxford Centre for Evidence-based Medicine-Levels of Evidence (March, 2009). RESULTS: Twelve studies met the inclusion criteria: 3 human studies and 9 animal studies. Levels of evidence ranged from level 1b to level 5. CONCLUSION: Most animal studies demonstrated a positive effect of acupuncture on cognitive impairment. However, the results of human studies were inconsistent. Further high-quality human studies with greater statistical power are needed to determine the effectiveness of acupuncture and an optimal protocol.