A Decision-Making Algorithm for Remote Digital Assessments of Alzheimer's Disease.

INTRODUCTION: Remote digital assessments (RDAs) such as voice recording, video and motor sensors, olfactory, hearing, and vision screenings are now starting to be employed to complement classical biomarker and clinical evidence to identify patients in the early AD stages. Choosing which RDA can be proposed to individual patients is not trivial and often time-consuming. This position paper presents a decision-making algorithm for using RDA during teleconsultations in memory clinic settings. METHOD: The algorithm was developed by an expert panel following the Delphi methodology. RESULTS: The decision-making algorithm is structured as a series of yes-no questions. The resulting questionnaire is freely available online. DISCUSSION: We suggest that the use of screening questionnaires in the context of memory clinics may help accelerating the adoption of RDA in everyday clinical practice.

Interaction between cognitive and motor disorders for risk screening of incident falls: results of an elderly population-based observational cohort study.

BACKGROUND: This study aims to examine (1) the association of "Emergency Room Evaluation and Recommendations" (ER2) cognitive and motor items with incident falls (i.e., ≥ 1), their recurrence (i.e., ≥ 2) and post-fall fractures and (2) the performance criteria (i.e., sensitivity, specificity) of the greater identified association for each incident fall outcome in older community dwellers. METHODS: 7147 participants (80.5 ± 3.8; 100% female) of the EPIDémiologie de l'OStéoporose (EPIDOS) observational population-based cohort study were recruited in France. Inability to name the day's date and the use of a walking aid and/or an history of falls were recorded at baseline. Incident outcomes, which were ≥ 1 fall, ≥ 2 falls and post-fall fractures, were collected every 4 months over a period of 4 years. RESULTS: The overall incidence of ≥ 1 fall was 26.4%, 6.4% for ≥ 2 falls, and 19.1% for post-fall fractures. Cox regressions revealed that the use of a walking aid and/or an history of falls [Hazard ratio (HR) ≥ 1.03 with P ≤ 0.011], inability to name the day's date (HR ≥ 1.05 with P ≤ 0.003), and their combination (HR ≥ 1.37 with P ≤ 0.002) were significantly associated with both incident falls, regardless of their recurrence, and post-fall fractures. INTERPRETATION: A significant positive association between ER2 cognitive and motor items, both, respectively, and in combination, with an overall incidence of falls, regardless of their recurrence, as well as with post-fall fractures was demonstrated. However, the low sensitivity and high specificity of the combination of ER2 items suggest that these items cannot be used for risk screening of fall outcomes in the older population.

"Emergency Room Evaluation and Recommendations" and Incident Hospital Admissions in Older People with Major Neurocognitive Disorders Visiting Emergency Department: Results of an Experimental Study.

INTRODUCTION: Older people with major neurocognitive disorders (MNCDs) visiting the emergency department (ED) are at high risk of hospital admissions. The "Emergency Room Evaluation and Recommendations" (ER2) tool decreases the length of stay (LOS) in the hospital when older people visiting ED are hospitalized after an index ED visit, regardless of their cognitive status. Its effect on hospital admissions has not yet been examined in older people with MNCD visiting ED. This study aimed to examine whether ER2 recommendations were associated with incident hospital admissions and LOS in ED in older people with MNCD visiting ED. METHODS: A total of 356 older people with MNCD visiting ED of the Jewish General Hospital (Montreal, Quebec, Canada) were recruited in this non-randomized, pre-post-intervention, single arm, prospective and longitudinal open label trial. ED staff and patients were blinded of the ER2 score, and patients received usual ED care during the observation period, whereas ED staff were informed about the ER2 score, and patients had ER2 tailor-made recommendations in addition to usual care during the intervention period. Hospital admissions and the LOS in ED were the outcomes. RESULTS: There were less incident hospital admissions (odds ratio ≤ 0.61 with p ≤ 0.022) and longer LOS in ED (coefficient beta ≥4.28 with p ≤ 0.008) during the intervention period compared to the observation period. DISCUSSION/CONCLUSION: ER2 recommendations have mixed effects in people with MNCD visiting ED. They were associated with reduced incident hospital admissions and increased LOS in ED, suggesting that they may have benefits in addition to usual ED care.

Improving the mental and physical health of older community-dwellers with a museum participatory art-based activity: results of a multicentre randomized controlled trial.

BACKGROUND: The aim of this randomized controlled trial (RCT) was to examine the mental and physical effects of a participatory art-based activity carried out at museums in older community-dwellers. METHODS: Based on a bicentre (the Montreal Museum of Fine Arts (MMFA), Montreal, Quebec, Canada; the Fuji Museum, Tokyo, Japan) single-blind RCT in two parallel groups (intervention group versus control group), 228 community-dwelling older adults (mean age 71.1 ± 5.4 years, 76.3% female) were enrolled. The intervention was a participatory art-based activity carried out at the MMFA and the Fuji Museum. The intervention group met weekly for 2 h over a 12-week period. The control group did not participate in any art-based intervention over the study period. Well-being was assessed before and after the first (M0) and the twelfth (M3) workshops, and quality of life and frailty before workshops at M0 and M3. These outcomes were assessed with standardized questionnaires with the same schedule in both groups. RESULTS: Well-being and quality of life improved significantly in the intervention group compared to the control group. Mixed results were observed with frailty. Although there were significantly more vigorous and fewer mildly frail participants by the end of the session when comparing intervention to control group participants, only a trend was observed in the decrease in mean value of the intervention group's frailty score. INTERPRETATION: This RCT confirmed that a participatory art-based activity performed weekly over a 3-month period may improve both mental and physical health in older community-dwellers. TRIAL REGISTRATION: NCT03679715; Title: A-Health RCT: Effects of Participatory Art-Based Activity on Health of Older Community Dwellers; First posted date: September 20, 2018; prospectively registered: https://clinicaltrials.gov/ct2/show/NCT03679715.

Implementing a Telehealth Support Tool for Community-Dwelling Older Adults During the COVID-19 Pandemic: A Qualitative Investigation of Provider Experiences.

During the COVID-19 pandemic, policymakers had to quickly offer telehealth services to address older adults' needs. This study aimed to understand the experiences of providers who implemented a telephone-based telehealth tool named Socio-Geriatric Evaluation (ESOGER), which assessed health and social isolation risks in community-dwelling older adults in Quebec (Canada). This qualitative study used 20 semi-structured online/phone interviews with health and social service providers coming from publicly-funded healthcare facilities and community organizations. We included adopters and non-adopters of the telehealth tool. Interviews were audio-recorded and transcribed verbatim. We used reflexive thematic analysis to interpret the data. Three dimensions of providers' practice influenced the tool's implementation: service organization, working conditions, and interactions with older adults. Participants reported that the tool fostered continuity of care, provided guidance for their pandemic-related new tasks, and helped identify and support socially isolated older adults. Challenges to implementation included limited appropriateness of the telehealth tool for diverse services, feasibility barriers to adopting a new tool amid the health crisis, and acceptability challenges with some older adults. Despite relevance of the telehealth tool for providers, organizational, professional, and interactional barriers could hinder implementation success. Participatory approaches to telehealth may be promising avenues for future policies in this field.

Motoric cognitive risk syndrome and incident dementia in older adults from the Québec NuAge cohort.

BACKGROUND: The co-occurrence of slow walking speed and subjective cognitive complaint (SCC) in non-demented individuals defines motoric cognitive risk syndrome (MCR), which is a pre-dementia stage. There is no information on the association between MCR and incident dementia in Québec's older population. OBJECTIVE: The study aims to examine the association of MCR and its individual components (i.e. SCC and slow walking speed) with incident dementia in community-dwelling older adults living in the province of Québec (Canada). DESIGN: Québec older people population-based observational cohort study with 3 years of follow-up. SETTING: Community dwellings. SUBJECTS: A subset of participants (n = 1,098) in 'Nutrition as a determinant of successful aging: The Québec longitudinal study' (NuAge). METHODS: At baseline, participants with MCR were identified. Incident dementia was measured at annual follow-up visits using the Modified Mini-Mental State (≤79/100) test and Instrumental Activity Daily Living scale (≤6/8) score values. RESULTS: The prevalence of MCR was 4.2% at baseline and the overall incidence of dementia was 3.6%. MCR (Hazard Ratio (HR) = 5.18, with 95% confidence interval (CI) = [2.43-11.03] and P ≤ 0.001) and SCC alone (HR = 2.54, with 95% CI = [1.33-4.85] and P = 0.005) were associated with incident dementia, but slow walking speed was not (HR = 0.81, with 95%CI = [0.25-2.63] and P = 0.736). CONCLUSIONS: MCR and SCC are associated with incident dementia in NuAge study participants.

Prognosis tools for short-term adverse events in older emergency department users: result of a Québec observational prospective cohort.

BACKGROUND: The "Program of Research on the Integration of Services for the Maintenance of Autonomy" (PRISMA-7) and "Emergency room evaluation and recommendations" (ER2) are both clinical tools used in Québec Emergency Departments (EDs) for screening of older ED users at higher risk of poor outcomes, such as prolonged length of stay (LOS) in EDs and in hospital. The study aimed to: 1) examine whether the PRISMA-7 and ER2 risk levels were associated with length of stays in ED and hospital, as well as hospital admission; and 2) compare the criteria performance (i.e., sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios and area under receiver operating characteristic curve) of the PRISMA-7 and ER2 high-risk levels for these three ED adverse events in Québec older patients visiting ED on a stretcher. METHODS: A total of 1905 older patients who visited the ED of the Jewish General Hospital (Montreal, Québec, Canada) on stretchers were recruited in this prospective observational cohort. Upon their ED arrival, PRISMA-7 and ER2 were performed. The outcomes were LOS in ED and in hospital, and hospital admission. RESULTS: The PRISMA-7 and ER2 risk levels were associated with length of stay in ED and hospital as well as with hospital admission. Prolonged stays and higher hospitalization rates were associated with high-risk levels, whereas those in low-risk level groups had significantly shorter LOS and a lower rate of hospital admission (P < 0.006). While performance measures were poor for both assessment tools, ER2 had a greater prognostic testing accuracy compared with PRISMA-7. CONCLUSION: PRISMA-7 and ER2 were both associated with incidental short-term ED adverse events but their overall prognostic testing accuracy was low, suggesting that they cannot be used as prognostic tools for this purpose.

Effects of participatory art-based painting workshops in geriatric inpatients: results of a non-randomized open label trial.

BACKGROUND: Art-based activities like painting workshops demonstrated health benefits in older individuals living in home care facilities. Few studies examined the effects of painting workshops in geriatric inpatients. AIM: The study aims to examine whether the participation in painting workshops performed in patients admitted to a geriatric acute care ward reduced the number of medications taken daily, use of psychoactive medications, the length of stay and inhospital mortality. METHODS: Based on a non-randomized open label trial, 79 inpatients who participated in painting workshops and 79 control inpatients were recruited in the geriatric acute care ward of the Jewish general hospital (Montreal, Quebec, Canada). Four outcomes were used: the number of medications taken daily and use of psychoactive medications the day of discharge to geriatric acute care ward, the length of hospital stay and inhospital mortality. RESULTS: The participation in Painting workshops were associated with a lower number of medications taken daily at discharge (Coefficient of regression ß = - 1.35 with P = 0.001) and lower inhospital mortality (odd ratio (OR) = 0.09 with P = 0.031). No significant association was reported with use of psychoactive medications and length of stay. CONCLUSION: The participation in painting workshops reduced the number of medications taken daily and incident inhospital mortality in geriatric inpatients admitted to a geriatric acute care ward, suggested a positive effect on health condition of this participatory art-based activity.

Screening for older inpatients at risk for long length of stay: which clinical tool to use?

BACKGROUND: Screening for inpatients at risk for long length of stay (LOS) is the first step of an effective hospital care plan for older inpatients. This study aims, in older adults admitted to a geriatric acute care ward, to examine and compare the 6-item brief geriatric assessment (BGA) and the "Programme de Recherche sur l'Intégration des Services pour le Maintien de l'Autonomie" (PRISMA-7) risk levels with long LOS, and to establish their performance criteria (i.e., sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios) for LOS. METHODS: Based on an observational, retrospective, cohort design, 166 inpatients aged ≥75 admitted to a geriatric acute care ward of a McGill University-affiliated hospital (Montreal, Quebec, Canada) were recruited. The risk levels of the 6-item BGA (low, moderate and high) and the PRISMA-7 (low versus high) were calculated from a baseline assessment. The LOS was subsequently calculated in number of days. RESULTS: Only the 6-item BGA high risk level was associated with a long LOS (Odds ratio = 1.1 with P = 0.028 and Hazard ratio = 2.1 with P = 0.004). Kaplan-Meier distributions showed that there was no significant difference in the delay of hospital discharge between the low and high-risk level reported by the PRISMA-7 (P = 0.381), whereas the 6-item BGA three risk levels differed significantly (P = 0.008), with individuals at high risk levels being discharged later when compared to those with low (P = 0.001) and moderate (P = 0.019) risk levels. Both tools' performance criteria were poor (i.e., < 0.70), except for PRISMA-7's sensitivity which was 100%. CONCLUSION: The 6-item BGA risk levels were associated with LOS, low risk-level being associated with short LOS and high-risk level with long LOS, but no association was reported with the PRISMA-7 risk levels. Both tools had poor performance criteria for long LOS, suggesting that they cannot be used as prognostic tools with current scientific knowledge.

Decreased risk of falls in patients attending music sessions on an acute geriatric ward: results from a retrospective cohort study.

BACKGROUND: Music has been shown to improve health and quality of life. It was suggested that music may also have an impact on gait stability and fall risk. Yet, few studies have exploited music in the hospital setting, and even less so in the geriatric population. Our objective was to examine the influence of music listening on the risk of falls by comparing the Morse Fall Scale score in patients admitted to a Geriatric Assessment Unit (GAU) who attended music listening sessions and in patients who did not attend music sessions. METHODS: This was a retrospective cohort study (mean follow-up 13.3 ± 6.8 days) which took place in a GAU, St. Mary's Hospital Center, Montreal. A total of 152 charts of participants, with a mean age of 85.7 ± 6.4 years and 88.2% female were reviewed and included. There were 61 participants exposed to the music listening sessions group and 91 in the non-exposed group matched for age, sex, cause and season of admission, and living situation. One-hour music sessions were provided to the patients by volunteer musicians. The Morse Fall Scale score upon admission and discharge as well as its variation (change from before to after exposure) were used as outcomes. Age, sex, living situation, reason for admission, season of admission, Mini Mental Status Examination score, number of therapeutic classes taken daily upon admission, use of psychoactive drugs upon admission and length of stay were used as covariates. RESULTS: The Morse Fall Scale score decreased significantly in the exposed group compared to the non-exposed group (p = 0.025) and represented a small to medium-sized effect, d = 0.395. The multiple linear regression model showed a significant association between the decrease of the Morse Fall Scale score and music exposure (B = - 17.1, p = 0.043). CONCLUSION: Participating in music listening sessions was associated with a decreased risk of falls in patients admitted to a GAU. Further controlled research is necessary to confirm these findings and to determine the mechanisms by which music listening impacts fall risk. TRIAL REGISTRATION: Clinical trial registry: ClinicalTrials.gov . Registration number: NCT03348657 (November 17th, 2017). Retrospectively registered.

Use of Vitamin K Antagonists and Brain Morphological Changes in Older Adults: An Exposed/Unexposed Voxel-Based Morphometric Study.

BACKGROUND: Vitamin K antagonists (VKAs) are commonly used for their role in haemostasis by interfering with the vitamin K cycle. Since vitamin K also participates in brain physiology, this voxel-based morphometric study aimed to determine whether the duration of exposure to VKAs correlated with focal brain volume reduction in older adults. METHODS: In this exposed/unexposed (1: 2) study nested within the GAIT (Gait and Alzheimer Interactions Tracking) cohort, 18 participants exposed to VKA (mean age 75 ± 5 years; 33.3% female; mean exposure 2,122 ± 1,799 days) and 36 matched participants using no VKA (mean age 75 ± 5 years; 33.3% female) underwent MRI scanning of the brain. Cortical grey and white matter volumes were automatically segmented using statistical parametric mapping. Age, gender, educational level, history of atrial fibrillation, type of MRI, and total intracranial volume were included as covariables. RESULTS: The duration of exposure to VKA correlated inversely across the whole brain with the subvolumes of two clusters in the grey matter (right frontal inferior operculum and right precuneus) and one cluster in the white matter (left middle frontal gyrus). In contrast, the grade of white matter hyperintensities did not differ according to the use of VKA. CONCLUSION: We found focal atrophies in older adults exposed to VKA. These findings provide new insights elucidating the effects of VKAs on brain health and function in older adults.

Association Between Falls and Brain Subvolumes: Results from a Cross-Sectional Analysis in Healthy Older Adults.

Falls are a consequence of gait instability. Cortical and subcortical abnormalities have been associated with gait instability but not yet with falls. This study aims to compare the global and regional brain subvolumes between healthy older fallers and non-fallers. A total of 77 healthy older individuals (23 fallers and 54 non-fallers, 69.8 ± 3.5 years; 45.5 % female) were included in this study using a cross-sectional design. Based on an a priori hypothesis, the following brain subvolumes were quantified from three-dimensional T1-weighted MRI using FreeSurfer software: total white matter abnormalities, total white matter, total cortical and subcortical gray matter, hippocampus, motor cortex, somatosensory cortex, premotor cortex, prefrontal cortex and parietal cortex volumes. Gait performances were also recorded. Age, sex, body mass index, comorbidities, use of psychoactive drugs, far-distance visual acuity, lower-limb proprioception, depressive symptoms and cognitive scores (Mini-Mental State Examination, Frontal Assessment Battery) were used as covariates. Fallers have more frequently depressive symptoms (P = 0.048), a lower far distance visual acuity (P = 0.026) and a higher coefficient of variation of stride time (P = 0.008) compared to non-fallers. There was a trend to greater subvolumes for the somatosensory cortex (P = 0.093) and the hippocampus (P = 0.060) in the falls group. Multiple logistic regressions showed that subvolumes of the somatosensory cortex and the hippocampus (P < 0.042) were increased in fallers compared to non-fallers, even after adjustment for clinical and brain characteristics. The greater subvolumes of the somatosensory cortex and hippocampus reported in fallers compared to non-fallers suggests a possible brain compensatory mechanism involving spatial navigation and integration of sensory information.

Blue light-filtering intraocular lenses and post-operative mood: a pilot clinical study.

The purpose of the study was to determine if implantation of blue-filtering intraocular lenses (IOLs) affects post-operative mood, inducing more depression, compared to patients undergoing implantation with conventional IOLs. The study was conducted at the Angers University Hospital, France. This was a prospective with a lowercase pilot study, including consecutive patients planned to undergo cataract surgery in both eyes within 1 week. The same type of IOL was used in both eyes of each patient. The choice of IOL was not randomized but driven by the habits and experience of each participating surgeon. Cognitively healthy patients (an MMSE score higher than 25) were assessed before and after surgery, using the 30-item geriatric depression scale (GDS) to seek symptoms of depression. Univariate and multiple logistic regressions were used to examine the association between the type of IOL and the 30-item GDS score improvement during the 3 months after lens implantation, while adjusting for participants' characteristics (age, visual acuity). Blue-filtering IOLs were used in 16 patients (mean ± standard deviation, 75.6 ± 7.5 years; 75 % female), and untinted IOLs in 18 patients (77.3 ± 6.9 years; 77.8 %female). Pre-operatively visual acuity and GDS scores were comparable in the two groups. The post-operative GDS score was improved by 1.91 ± 3.10 points in the whole sample (P = 0.002), as well as in each subgroup of patients. Three months after surgery, the mean change in GDS score did not differ between groups (P = 0.365), nor did the mean visual acuity (P = 0.198).

Assessment of solid cancer treatment feasibility in older patients: a prospective cohort study.

PURPOSE: To assess solid cancer treatment feasibility in older patients. METHODS: Between 2007 and 2010, 385 consecutive elderly patients (mean age: 78.9 ± 5.4 years; 47.8% males) with solid malignancies referred to two geriatric oncology clinics were included prospectively. We recorded feasibility of first-line chemotherapy (planned number of cycles in patients without metastases and three to six cycles depending on tumor site in patients with metastases), surgery (patient alive 30 days after successfully performed planned surgical procedure), radiotherapy (planned dose delivered), and hormonal therapy (planned drug dose given), and we recorded overall 1-year survival. RESULTS: Main tumor sites were colorectal (28.6%), breast (23.1%), and prostate (10.9%), and 47% of patients had metastases. Planned cancer treatment was feasible in 65.7% of patients with metastases; this proportion was 59.0% for chemotherapy, 82.6% for surgery, 100% for radiotherapy, and 85.2% for hormonal therapy. In the group without metastases, feasibility proportions were 86.8% overall, 72.4% for chemotherapy, 95.7% for surgery, 96.4% for radiotherapy, and 97.9% for hormonal therapy. Factors independently associated with chemotherapy feasibility were good functional status defined as Eastern Cooperative Oncology Group performance status <2 (p < .0001) or activities of daily living >5 (p = .01), normal mobility defined as no difficulty walking (p = .01) or no fall risk (p = .007), and higher creatinine clearance (p = .04). CONCLUSION: Feasibility rates were considerably lower for chemotherapy than for surgery, radiotherapy, and hormonal therapy. Therefore, utilization of limited geriatric oncology resources may be optimized by preferential referral of elderly cancer patients initially considered for chemotherapy to geriatric oncology clinics.

Gait control and executive dysfunction in early schizophrenia.

Dysexecutive functioning, which is described as an enduring core feature of schizophrenia, has been associated with gait disorders. However, few studies have reported gait disorders in schizophrenia patients. The objective of this study was to examine the association between executive dysfunction and gait performance in recent-onset schizophrenia patients using the dual task paradigm. Thirty-two subjects participated to the study: 17 with recent-onset schizophrenia and 15 healthy age-matched controls. Executive functions were evaluated using the Frontal Assessment Battery, Stroop and Trail-Making tests. Mean values and coefficients of variation (CV) of the temporal gait parameters while single tasking (just walking) and while dual tasking (walking and forward counting, walking and backward counting, walking and verbal fluency) were measured using the SMTEC(®)-footswitch system. We focused on the CV of stride time as this measure has been shown to be the most representative parameter of higher gait control. A strong effect of the stride time was found in the group factor for the verbal fluency dual-task when compared to controls (Cohen's d mean = 1.28 and CV = 1.05). The effect was lower in the other dual tasks, and insignificant in the single task of walking. This study shows that patients exhibit higher stride-to-stride variability while dual tasking than controls. It also shows a stronger impact of verbal fluency on gait regularity compared to the other dual tasks revealing a relationship between the executive dysfunction and gait modification. Those results are in line with the idea that schizophrenia implies not only cognitive but also motor functioning and coordination impairment.

Hypovitaminosis D and executive dysfunction in older adults with memory complaint: a memory clinic-based study.

BACKGROUND: Hypovitaminosis D is associated with executive dysfunction as a whole. The purpose of this cross-sectional study was to determine whether lower vitamin D levels were associated with mental flexibility, information updating, or cognitive and motor inhibition among older adults. METHODS: One hundred Caucasian older community dwellers with memory complaint (mean, 71.02 ± 0.74 years; 52.0% female) were divided into 3 groups according to serum 25-hydroxyvitamin D (25-OHD) concentration (deficiency <25 nmol/l, insufficiency 25-50 nmol/l, sufficiency >50 nmol/l). Executive functions were assessed with error rates by executing the Trail Making Test-B (TMT-B) for mental flexibility, the N-Back Test for information updating, the Stroop Interference Test for cognitive inhibition, and the Go/No-Go score for motor inhibition. Age, gender, BMI, education level, number of morbidities, depressive symptoms, Mini-Mental State Examination score, calcemia, estimated glomerular filtration rate and season tested were considered as potential confounders. RESULTS: Compared to participants with vitamin D insufficiency and sufficiency, those with vitamin D deficiency had a poorer TMT-B performance (p = 0.019 and p = 0.017, respectively) but similar N-Back (p = 0.175), Stroop (p = 0.135) and Go/No-Go (p = 0.224) scores. Cognitive performance did not differ between participants with insufficient and sufficient vitamin D levels. Vitamin D deficiency was associated with poorer performance on TMT-B (adjusted ß = 1.48, p = 0.011), but not on N-Back (p = 0.665), Stroop (p = 0.817) or Go/No-Go (p = 0.971). CONCLUSION: Vitamin D deficiency was associated with poorer mental flexibility among older community dwellers with memory complaint.

Motor cortex and gait in mild cognitive impairment: a magnetic resonance spectroscopy and volumetric imaging study.

Gait disorders are common in the course of dementia, even at the stage of mild cognitive impairment, owing to probable changes in higher levels of motor control. Since motor control message is ultimately supported in the brain by the primary motor cortex and since cortical lesions are frequent in the dementia process, we hypothesized that impairments of the primary motor cortex may explain the early gait disorders observed in mild cognitive impairment. Our purpose was to determine whether the neurochemistry of the primary motor cortex measured with proton magnetic resonance spectroscopy, and its volume, were associated with gait performance while single and dual-tasking in mild cognitive impairment. Twenty community dwellers with mild cognitive impairment, aged 76 years (11) [median (interquartile range)] (30% female) from the 'Gait and Brain Study' were included in this analysis. Gait velocity and stride time variability were measured while single (i.e. walking alone) and dual tasking (i.e. walking while counting backwards by seven) using an electronic walkway (GAITRite System). Ratios of N-acetyl aspartate to creatine and choline to creatine and cortical volume were calculated in the primary motor cortex. Participants were categorized according to median N-acetyl aspartate to creatine and choline to creatine ratios. Age, gender, body mass index, cognition, education level and subcortical vascular burden were used as potential confounders. Participants with low N-acetyl aspartate to creatine (n = 10) had higher (worse) stride time variability while dual tasking than those with high N-acetyl aspartate to creatine (P = 0.007). Those with high choline to creatine had slower (worse) gait velocity while single (P = 0.015) and dual tasking (P = 0.002). Low N-acetyl aspartate to creatine was associated with increased stride time variability while dual tasking (adjusted ß = 5.51, P = 0.031). High choline to creatine was associated with slower gait velocity while single (adjusted ß = -26.56, P = 0.009) and dual tasking (adjusted ß = -41.92, P = 0.022). Cortical volume correlated with faster gait velocity while single (P = 0.029) and dual tasking (P = 0.037), and with decreased stride time variability while single tasking (P = 0.034). Finally, the probability of exhibiting abnormal metabolite ratios in the primary motor cortex was 63% higher among participants with major gait disturbances in dual task. Those with compromised gait velocity in dual task had a 2.05-fold greater risk of having a smaller cortical volume. In conclusion, the neurochemistry and volume of the primary motor cortex were associated with gait performance while single and dual tasking. Stride time variability was mainly sensitive to neuronal function (N-acetyl aspartate to creatine), whereas gait velocity was more affected by inflammatory damage (choline to creatine) and volumetric changes. These findings may contribute to a better understanding of the higher risks of mobility decline and falls in subjects with mild cognitive impairment.

Higher gait variability is associated with decreased parietal gray matter volume among healthy older adults.

The objectives of this study were to examine the association of stride time variability (STV) with gray and white matter volumes in healthy older adults, and to determine the specific location of any parenchymal loss associated with higher STV. A total of 71 participants (mean age 69.0 ± 0.8 years; 59.7 % female) were included in this study. All participants had a 1.0 Tesla 3D T1-weighted MRI of the brain to measure gray and white matter volumes. STV was measured at steady-state self-selected walking speed using an electronic footswitch system. We found an association between higher STV and lower gray matter volume in the right parietal lobe (e.g., angular gyrus, Brodmann area 39, cluster corrected pFWE = 0.035). There were no significant associations between STV and higher gray matter volume or change in white matter volume. To the best of our knowledge this study is the first to identify a significant association of higher STV with lower right parietal gray matter volume in healthy older adults.