Background: Physical frailty is well known to be strongly associated with malnutrition, but the combined impact of physical frailty and cognitive impairment among non-demented older persons (cognitive frailty) on malnutrition prevalence is not well documented. Design: Cross-sectional cohort study. Setting and Participants: Community-dwelling older Singaporeans aged ≥55y (n=5414) without dementia in the Singapore Longitudinal Ageing Study (SLAS-1 and SLAS-2). Measurements: The Mini Nutritional Assessment – short form (MNA-SF) and Nutrition Screening Initiative (NSI) Determine Checklist were used to determine their nutritional status. Participants were categorized as cognitive normal (CN) or cognitive impaired (CI) by Mini Mental State Examination (MMSE<=23), as pre-frail (PF) (score=1-2) or frail (F) (score=3-5) using Fried’s criteria, and as cognitive pre-frail (PF+CI) or cognitive frail (F+CI). Results: The prevalence of cognitive frailty was 1.6%, and cognitive pre-frailty was 5.5% (total, 7.1%). The prevalence of MNA malnutrition was 2.4%, and NSI high nutritional risk was 6.3%. The prevalence of MNA malnutrition was lowest among Robust-CN and highest among Frail-CI (0.5% in Robust-CN, 0.6% in Robust-CI, 2.8% in Pre-frail-CN, 7.3% in Pre-frail-CI, 15.4% in Frail-CN, and 23.1% in Frail-CI). Similarly, the prevalence of NSI high nutritional risk was lowest in Robust-CN (3.7%) and highest in Frail-CI (13.6%). Adjusted for sociodemographic and health status, pre-frailty/frailty-CI versus Robust-CN was associated with the highest odds ratio of association with MNA malnutrition (OR=8.16, p<0.001), although not the highest with NSI high nutritional risk (OR=1.48, p=0.017). Conclusions: An extraordinary high prevalence of malnutrition was observed among older adults with cognitive frailty who should be specially targeted for active intervention.

PurposeCommunity-based programs can increase and sustain physical activity participation in older adults, even for those who are physically frail. We studied the feasibility and potential effect of a 12-week structured Functional Power Training (FPT) program involving high velocities and low loads for older adults conducted in a common area of their housing estate.Patients and methodsThe structured FPT program was conducted in collaboration with a health promotion social enterprise and a community service provider based in a public housing site. We recruited nine inactive residents as participants to the single, group-based, twice-weekly program. Attendance and adverse event(s) were recorded throughout the program. The Short Physical Performance Battery, Timed Up and Go (TUG), and 30s Sit-to-Stand tests were used to assess functional outcomes pre- and postprogram. The FRAIL Scale was used to assess their frailty status, and a postprogram experience survey was conducted.ResultsEight subjects (aged 74±10 years) completed the program with an average overall attendance of 90.3%, with at least five participants present for each session. Changes in functional outcomes showed a moderate-to-large effect with significant improvement in TUG (p<0.01). In addition, participants either reversed or maintained their frailty status (p<0.01). Overall, the program was perceived to be well structured, engaging, as well as providing physical and psychosocial benefits. No exercise-related adverse events occurred during the program, and participants were keen to recommend this program to others.ConclusionCommunity-based structured FPT is safe and feasible for frail older adults, with the potential to improve function and reverse frailty status.

Transcranial magnetic stimulation (TMS) studies have demonstrated that unilateral muscle contractions in the upper limb produce motor cortical activity in both the contralateral and ipsilateral motor cortices. The increase in excitability of the corticomotor pathway activating the resting limb has been termed “cross-activation”, and is of importance due to its involvement in cross-education and rehabilitation. To date, very few studies have investigated cross-activation in the lower limb. Sixteen healthy participants (mean age 29 ± 9 years) took part in this study. To determine the effect of varying contraction intensities in the lower limb, we investigated corticomotor excitability and intracortical inhibition of the right rectus femoris (RF) while the left leg performed isometric extension at 0%, 25%, 50%, 75% and 100% of maximum force output. Contraction intensities of 50% maximal force output and greater produced significant cross-activation of the corticomotor pathway. A reduction in silent period duration was observed during 75% and 100% contractions, while the release of short-interval intracortical inhibition (SICI) was only observed during maximal (100%) contractions. We conclude that increasing isometric contraction intensities produce a monotonic increase in cross-activation, which was greatest during 100% force output. Unilateral training programs designed to induce cross-education of strength in the lower limb should therefore be prescribed at the maximal intensity tolerable.

Key point summary  Activity in the primary motor cortices of both hemispheres increases during unilateral movement preparation, but the functional role of ipsilateral motor cortex activity is unknown. Ipsilateral motor cortical activity could represent subliminal "motor planning"for the passive limb. Alternatively, it could represent the state of the active limb, to support coordination between the limbs should a bimanual movement be required.

Key point summary Activity in the primary motor cortices of both hemispheres increases during unilateral movement preparation, but the functional role of ipsilateral motor cortex activity is unknown. Ipsilateral motor cortical activity could represent subliminal "motor planning" for the passive limb. Alternatively, it could represent the state of the active limb, to support coordination between the limbs should a bimanual movement be required. Here we assessed how preparation of forces toward different directions, with the left wrist, alters evoked responses to transcranial magnetic stimulation of left motor cortex. Preparation of a unilateral movement caused excitability increases in ipsilateral motor cortex that reflected forces produced with the active limb in an intrinsic (body-centered), rather than an extrinsic (world-centered), coordinate system.  These results suggest that ipsilateral motor cortical activity prior to unilateral action reflects the state of the active limb, rather than subliminal motor planning for the passive limb. AbstractCorticospinal excitability is modulated for muscles on both sides of the body during unilateral movement preparation. For the effector, there is a progressive increase in excitability, and a shift in direction of muscle twitches evoked by transcranial magnetic stimulation (TMS) toward the impending movement. By contrast, the directional characteristics of excitability changes in the opposite (passive) limb have not been fully characterized. Here we assessed how preparation of voluntary forces towards four spatially distinct visual targets with the left wrist alters muscle twitches and motor evoked potentials (MEPs) elicited by TMS of left motor cortex. MEPs were facilitated significantly more in muscles homologous to agonist rather than antagonist muscles in the active limb, from 120 ms prior to voluntary EMG onset. Thus, unilateral motor preparation has a directionally-specific influence on pathways projecting to the opposite limb that corresponds to the active muscles rather than the direction of movement in space. The directions of TMS-evoked twitches also deviated toward the impending force direction of the active limb, according to muscle-based coordinates, following the onset of voluntary EMG. The data indicate that preparation of a unilateral movement increases task-dependent excitability in ipsilateral motor cortex, or its downstream projections, that reflect the forces applied by the active limb in an intrinsic (body-centered), rather than an extrinsic (worldcentered), coordinate system. The results suggest that ipsilateral motor cortical activity prior to unilateral action reflects the state of the active limb, rather than subliminal motor planning for the passive limb.