Discrepancy in Fluid and Crystallized Intelligence: An Early Cognitive Marker of Dementia from the LASI-DAD Cohort.

Background: Cognitive aging is a complex phenomenon, which comprises various cognitive skills, broadly categorized into fluid and crystallized intelligence. Crystallized intelligence (gc) tends to be maintained, as opposed to fluid intelligence (gf), which tends to decline rapidly with age. The association of the two with cognitive decline remains a matter of conjecture requiring further research. Aim: The aim of the study was to identify the variables of gc and gf from a population data of Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD) study and investigate its relationship with the onset of cognitive impairment using discrepancy analysis against neuropsychological tests. Methods: This analysis of data from LASI-DAD study was carried out on a sample of 3,223 participants. They were assessed on extensive thirteen cognitive tests and one subjective test of cognition. Standardized score was used for discrepancy analysis. Fluid ability minus crystallized ability was used to assess the cognitive impairment. Any statistical significance with the score difference >0.99 SD was defined as a presence of cognitive decline. Hindi Mental Status Examination (HMSE) and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) were used as gold standard. Results: With increased discrepancy score, each cognitive parameter score declined which was found to be statistically significant. In HMSE (Normal = 25.81 ± 3.39; Impaired = 23.17 ± 3.54; p = <0.001), there was a drop of 2 point scores in identifying cognitive impairment in the population sample as per the gold standard. A similar trend was evident in other neurocognitive domains as well. Conclusion: Crystallized-fluid intelligence discrepancy analysis has a strong potential in predicting the onset of cognitive decline ahead of time, facilitating early intervention.

A novel approach to correlate the salivary exosomes and their protein cargo in the progression of cognitive impairment into Alzheimer's disease.

BACKGROUND: Cognition is the ability of a person to think, remember, and interconnect ideas from various dimensions to strive for solutions. Cognitive defects accompany all forms of dementia and the decline in cognition is a most feared aspect. Mild cognitive impairment is considered as a transitional phase and the progressive loss in cognition can finally lead to Alzheimer's disease. NEW METHOD: In this study, we demonstrated a novel method based on nanoparticle tracking analysis (NTA) technique to directly correlate salivary exosomes concentration with the progression of cognitive impairment (CI) in Alzheimer's disease (AD).This could open up the possibility for an early and cost-effective screening of Alzheimer's disease. RESULTS: Using our novel method, the total salivary exosomes concentration was measured by NTA technique, followed by validation of key exosomal cargo proteins through an automated western blot analyzer. We observed significant differences in salivary exosomes concentration among the groups of cognitively impaired and Alzheimer's disease patients (p = 0.0023) compared to the healthy control cohort. The method was validated through CD63 (exosomes surface marker) fluorescent antibody based quantification, which yielded a similar outcome (p = 0.0286). We further corroborated our findings with the expression level of oligomeric amyloid-beta, phosphorylated-tau protein from salivary exosomes. The Aß oligomer/fibril abundance (p = 0.0291), phospho-tau (p = 0.0325) and Aß protein abundance (p = 0.0198) was significantly higher in Alzheimer's and cognitively impaired patients in comparison to the healthy controls. COMPARISON WITH EXISTING METHOD(S): There are few molecular biomarkers available to differentiate between various stages of cognitive impairment. Moreover, the current methodologies utilizing the few biomarkers available are either invasive or expensive; also, for a patient with mild cognitive complains, it is impractical to use these as a screening tool. CONCLUSION: Our initial results indicate that the salivary exosomes concentration based on the nano-tracking technique has the potential to be used as a cost-effective screening method for early disease detection.

Prevalence and predictors of falls in a health-seeking older population: An outpatient-based study.

BACKGROUND: Falls are one of the major causes of disability in older people. A wide range of risk factors for falls are described according to setting - inpatient, nursing homes and community. The aim of this study was to identify the risk factors for falls in an outpatient setting. METHODS: In this cross-sectional observational study, 160 consenting subjects were enrolled randomly, from the Geriatric Medicine outpatient department, All India Institute of Medical Sciences, New Delhi, India. Non-ambulatory, seriously ill subjects were excluded. The subjects underwent brief evaluation including falls and geriatric assessment. They were grouped into fallers and non-fallers. A multivariable logistic regression analysis was used to identify the factors associated with falls. RESULTS: The prevalence of falls was 23.75% (38/160). Women were proportionately higher (26.31%) in the fallers group vis-à-vis 19.67% in the non-fallers group. After multivariate analysis, opioids (odds ratio [OR] 5.24 [95% CI, 2.0 18-13.611]), vision impairment (OR 2.71 [95% CI, 1.050-07.011]), fear of falling (OR 3.17 [95% CI, 1.167-08.629]), instrumental activity of daily living (IADL) impairment (OR 3.41 [95% CI, 1.251-09.301]), anti-anginal medications (OR 8.90 [95% CI, 0.997-79.564]) and self-employment (OR 5.37 [95% CI, 1.058-27.329]) were associated with falls. Adequate nutrition (OR 0.82 [95% CI, 0.688-00.976]) and caregiver support (OR 0.46 [95% CI, 0.275-00.801]) were protective of falls. CONCLUSION: We identified the multi-factorial etiology of falls. Patients having any of the above risk factors should undergo detailed fall risk assessment and preventive measures afterwards.

Low one-repetition-maximum knee extension is significantly associated with poor grip strength, female sex, and various aging-related syndromes.

OBJECTIVE: Muscle strength in older adults is usually measured according to grip strength, which demonstrates upper muscle strength only. In this study, we used one-repetition-maximum (1-RM) knee extension as a measure of lower limb strength and assessed its relationship with grip strength and various geriatric syndromes. METHODS: One hundred outpatients over the age of 65 years were recruited from a geriatric medicine center in India. The 1-RM knee extension was measured along with grip strength. Various geriatric conditions were measured, such as: nutrition (using the Mini Nutritional Assessment), cognition (Hindi Mental State Questionnaire), depression (5-item Geriatric Depression Scale), frailty (Fried and Rockwood models), and osteoporosis (dual-energy X-ray absorptiometry scan). Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria. RESULTS: The mean age of participants was 72.5 years with 69% of them male. Median values of 1-RM knee extension and grip strength were 2.29 (0.5-10.0) and 17.5 (0-78), respectively. The 1-RM knee extension had moderate correlation with grip strength (r = 0.491, P < 0.001). Among demographic details, only female sex (P < 0.001) was significantly associated with lower 1-RM values. Further, after adjusting for age and sex, lower value of log10 1-RM knee extension was found to be significantly associated with malnutrition (P = 0.001), dementia (P = 0.016), depression (P = 0.047), frailty (Rockwood: P = 0.049; Fried: P = 0.011), and sarcopenia (P < 0.001). CONCLUSION: The 1-RM knee extension has only moderate correlation with grip strength. A lower 1-RM knee extension value is significantly associated with female sex and various geriatric conditions, such as malnutrition, dementia, depression, frailty, and sarcopenia.

Raised serum cystatin C can be a potential biomarker of frailty detected by cumulative deficit model.

OBJECTIVE: Identification of frailty by clinical criteria is often delayed to the advanced stage. A reliable biomarker to identify frailty or its risk does not currently exist. We aimed to determine the association between serum cystatin C and frailty in subjects without renal dysfunction. METHODS: We carried out a cross-sectional observational study in the Department of Geriatric Medicine, All India Institute of Medical Sciences, New Delhi, India. The study involved 125 participants, aged 65 years or older. Frailty status was assessed with Frailty Index criteria (cumulative deficit model). Serum cystatin C was estimated with the nephelometry method and its association with frailty was analyzed. RESULTS: Mean age of the study sample was 76.32 years with 72 (57.6%) male and 53 (42.4%) female participants. Seventy-three subjects were frail; the mean cystatin C levels in the frail and non-frail groups were 1.28 mg/L (±0.39) and 1.12 mg/L (±0.27), respectively, and the difference was significant (P < 0.05). A cutoff of 1.12 mg/L was found to be 60.27% sensitive and 57.69% specific in identification of frailty. Multivariate analysis showed that higher cystatin C level was associated with 2.52 (1.05-6.02) times the risk of being frail. CONCLUSION: Higher levels of cystatin C were found in frail subjects. Cystatin C seems to be a promising marker for identifying frailty in older adults without renal abnormalities.

Normal gait speed, grip strength and thirty seconds chair stand test among older Indians.

INTRODUCTION: Gait speed, maximum grip strength and thirty seconds chair stand test are quick, reliable measures of functional capacity in older adults. The objective of this study was to develop normative data of the said parameters, which is lacking in older Indians. METHODOLOGY: In a cross sectional study, 723 participants of ≥60 years without any morbidity, were recruited with written consent at Geriatric Medicine clinic of All India Institute of Medical sciences, New Delhi. Time taken to walk comfortably (4m) was taken as Gait speed. Maximum grip strength was assessed by using dynamometer by pressing it for 3 times in each hand, and the best of six values noted. Thirty second chair stand was assessed by the number of repetitions to stand and sit from a chair in thirty second. RESULT: The Cut-off (25th percentile) of gait speed for both male and female in all age group was 0.6m/s. The Cut-off for maximum grip strength in 60-65 years, 66-70 years and >70 years for male were 20, 15 and 15 and for females were 8, 6 and 6 in kg, respectively. The Cut-off for thirty second chair stand test in 60-65 years, 66-70 years and >70 years for male were 10, 9 and 8 and for females was 8, 8 and 7, respectively. CONCLUSION: These normative data would be useful to the clinicians and researcher as Indian reference value, which is less as compared to western data. Community based multi-centre study is needed.