Brain Structural Correlates of Obstacle Negotiation in Mild Cognitive Impairment: Results from the Gait and Brain Study

INTRODUCTION

Mild cognitive impairment (MCI) affects obstacle negotiation capabilities, potentially increasing the risk of falls in older adults. However, it is unclear whether smaller brain volumes typically observed in older individuals with MCI are related to the observed hazardous obstacle negotiation in this population.

METHODS

A total of 93 participants (71.9 ± 5.36 years of age; MCI = 53/control = 40) from the Gait and Brain Study were analyzed. Gray matter (GM) volumes from the frontal, temporal, and parietal lobes were entered in the analysis. Gait performance was recorded using a 6-m electronic walkway during two cognitive load conditions while approaching and stepping over an obstacle: (1) single-task and (2) while counting backwards by 1s from 100 (dual-task). Anticipatory adjustments in gait performance to cross an "ad hoc" obstacle were electronically measured during pre-crossing phases: early (3 steps before the late phase) and late (3 steps before obstacle). Association between the percentage of change in average gait speed and step length from early to late (i.e., anticipatory adjustments) and GM volumes was investigated using multivariate models adjusted for potential confounders.

RESULTS

Anticipatory adjustments in gait speed (Wilks' lambda: 0.35; Eta2: 0.64; p = 0.01) and step length (Wilks' lambda: 0.33; Eta2: 0.66; p = 0.01) during dual-task conditions were globally associated with GM volumes in MCI. Individuals with MCI with smaller GM volumes in the left inferior frontal gyrus, left hippocampus, right hippocampus, and right entorhinal cortex made significantly fewer anticipatory gait adjustments prior to crossing the obstacle.

CONCLUSION

Frontotemporal atrophy may affect obstacle negotiation capabilities potentially increasing the risk of falls in MCI.

Practical Implications for Strength and Conditioning of Older Pre-Frail Females

Approaches to and benefits from resistance training for non-compromised older adults are well known. Less is understood about resistance training with pre-frail older adults, and even less information is available on the practical approaches to delivery. Herein, we describe an approach in pre-frail females who undertook a multi-component exercise intervention, inclusive of high-intensity, free-weight, functional resistance training. Capitalizing on the principle of overload is possible and safe for pre-frail females through constant reassurance of ability and adjustments in technique. Making exercise functionally relevant, for example, a squat is the ability to get on and off a toilet, resonates meaning. Older pre-frail females are affected by outside (clinical) influences. The exercise participant, and extraneous persons need to be educated on exercise approaches, to increase awareness, debunk myths, and enhance support for participation. Identification of individuality in a group session offers ability to navigate barriers for successful implementation.

Multi-Component Exercise with High-Intensity, Free-Weight, Functional Resistance Training in Pre-Frail Females: A Quasi-Experimental, Pilot Study

BACKGROUND

No study has performed an exercise intervention that included high-intensity, free-weight, functional resistance training, and assessed frailty status as an inclusion criteria and outcome measure via original, standardized tools, in pre-frail females.

OBJECTIVES

Determine if the intervention strategy is not only feasible and safe, but can also improve frailty status, functional task performance, and muscle strength.

DESIGN

Pilot, quasi-experimental.

SETTING

Community.

PARTICIPANTS

20 older-adults with pre-frailty characteristics.

INTERVENTION

12-weeks (3 days/week, 45-60 minutes/session) of multi-component exercise, inclusive of aerobic, resistance, balance and flexibility exercises. The crux of the program was balance and resistance exercises, the latter utilized high-intensity, free-weight, functional resistance training. The control group maintained their usual care.

MEASUREMENTS

1) Feasibility and safety (dropout, adherence, and adverse event); 2) Frailty (Frailty Phenotype, Clinical Frailty Scale, and gait speed); 3) Functional task performance (grip strength and sit-to-stand time); and 4) Isometric and isotonic strength of the knee extensors and elbow flexors.

RESULTS

No participants dropped out of the intervention or experienced an adverse event, and adherence averaged 88.3%. The exercise group became less frail, whereas the control group became more frail. There was a significant within-group improvement in exercise participants gait speed (p ≤ 0.01, +0.24 m/sec), grip strength (p ≤ 0.01, +3.9 kg), and sit-to-stand time (p ≤ 0.01, -5.0 sec). There was a significant within-group improvement in exercise participants knee extension isometric torque (p ≤ 0.05, +7.4 Nm) and isotonic velocity (p = ≤ 0.01, +37.5 ˚/sec). Elbow flexion isotonic velocity significantly declined within the control group (p ≤ 0.01, -20.2 ˚/sec) and demonstrated a significant between-group difference (p ≤ 0.05, 40.73 ˚/sec) post-intervention.

CONCLUSIONS

The intervention strategy appears to be feasible and safe, and may also improve frailty status, functional task performance, and muscle strength. These results help calculate effect size for a future randomized controlled trial.

The Effect of High Dose Vitamin D3 on Physical Performance in Frail Older Adults. A Feasibility Study

BACKGROUND

Vitamin D deficiency is ubiquitous in frailty but the effectiveness of vitamin D supplementation to improve outcomes in frail individuals is unclear. It has been postulated that higher than the current recommended doses (800 IU/day) may be needed to achieve a neuromuscular effect in frail individuals.

OBJECTIVES

1) determine if 4000 IU per day of vitamin D3 is safe for frail older adults; and 2) establish the efficacy of this dose to improve physical performance outcomes in this population.

DESIGN

Open-label, feasibility study.

SETTING

Community retirement centre.

PARTICIPANTS

40 older adults with frail or pre-frail characteristics.

INTERVENTION

4000 IU of vitamin D3 and 1200 mcg of calcium carbonate daily for four months.

MEASUREMENTS

Physical performance (grip strength, gait speed and short physical performance battery score), cognitive health and vitamin D and iPTH serum levels before and after the intervention.

RESULTS

Frail individuals improved short physical performance battery score (1.19, p = 0.005), fast gait speed (4.65, p = 0.066) and vitamin D levels (7.81, p = 0.011). Only frail females made a significant improvement in grip strength (1.92, p = 0.003). Stratifying the sample by baseline vitamin D levels revealed that participants with vitamin D insufficiency (≤ 75 nmol/L) significantly improved short physical performance battery score (1.06, p = 0.04), fast gait speed (6.28, p = 0.004) and vitamin D levels (25.73, p = <0.0001). Pre-frail individuals, as well as those with sufficient vitamin D levels (> 75 nmol/L) made no significant improvement in any outcome.

CONCLUSIONS

Vitamin D supplementation using 4000 IU/daily is safe and has a modest beneficial effect on physical performance for frail individuals and those with insufficient vitamin D levels. Participants with vitamin D insufficiency (≤ 75 nmol/L) showed greater benefits. Our feasibility study provides results to help calculate effect size for a future RCT.

Developmental and intellectual differences in self-report and strategy use

The veridicality and reactivity of children's self-report of covert and overt memory strategies were investigated in a task allowing a direct comparison of self-report and the strategy observed. External memory strategies (e.g., moving objects) were investigated with 7-, 9-, 11-, and 17-year-old typical children and 11- and 17-year-old children with mild mental retardation. Participants placed objects in specified spatial locations after hearing sequences of tape-recorded sentences. After each trial, half of the children immediately reported the strategy used. There were strong positive correlations between the frequency of reported strategy use and observed strategy use. Self-reports were accurate but not always complete. There was no effect of the self-reporting procedure on measures of verbal strategies, external memory strategies, and accuracy of recall. Children were less likely to report strategies not related to recall; these results are compatible with a "goal-sketch" mechanism.

Instructional and contextual effects on eternal memory strategy use in young children

Young children's ability to devise external representations in problem-solving tasks has not been fully examined. The present two experiments investigated children's creation and use of external representations (i.e., external representation strategies) in different conditions. In each experiment, 4- and 6-year-old children listened to a series of sentences (e.g., "The doll is on the table") and were required to remember where to place the objects named in the sentences. In Experiment 1, direct training increased the use of external representations. When the salience of task dimensions increased in Experiment 2, children's external representation strategies also increased. Four-year-old children showed a utilization deficiency in external representation strategy use in the prompt conditions, but not in the training condition. Thus, young children require additional situational support before they demonstrate cognitive competencies.

External and verbal strategies in children with and without mild mental retardation

External memory strategies (e.g., moving objects) were investigated in 11- and 17-year-old children with mild mental retardation and 7-, 9-, 11- and 17-year-old children without mental retardation (N = 95). In an external memory task, after hearing from 1 to 7 sentences, subjects placed objects in specified spatial locations. In the verbal memory task, subjects recalled sentences orally. Target-oriented strategies increased with the number of sentences and were positively related to accuracy. There was no difference between children with mental retardation and their age peers in object-oriented strategies. For all groups, external strategies were used more frequently than verbal strategies. These results show that children with mental retardation have more strategy competencies than reported in studies of covert verbally based strategies.

Intellectual and developmental differences in external memory strategies

External memory strategies (e.g., moving objects) were investigated in 11-year-old children with mild mental retardation and 7- and 11-year-olds without mental retardation. Participants attempted to place objects at specified spatial locations after hearing sequences of tape-recorded instructions. During baseline, children with mental retardation and 7-year-olds used external strategies more frequently than did 11-year-olds. All three groups used external strategies after prompting that represented the correct spatial locations, and all used the same tactics. In contrast to expected deficiencies in the use of strategies, results show areas of overlap in strategy capabilities among the groups.

A comparison of cycloplegic refraction to the near retinoscopy technique for refractive error determination

The near retinoscopy technique of refractive error determination was compared to the standard method of cycloplegic refraction using 10 "infants" (3-12 months of age) and 10 "children" (32-109 months of age). There was a significant difference between the techniques for both sphere and cylinder power. Although there was no interaction of refractive technique and age group, the difference between near retinoscopy and cycloplegic refractive error tended to be larger for infants than for children. No significant difference was found when the average refractive values were compared for monocular or binocular conditions and no significant effect was found for either gender or laterality (right versus left eye). Based on these findings, it is suggested that caution be used in substituting the near retinoscopy technique for cycloplegic refraction even utilizing a "correction" factor for the dioptric difference between techniques.

Comparison and message-formulation skills in the referential communication of severely mentally retarded children

The importance of comparison and message-formulation skills in referential communication was studied with severely mentally retarded children. A store game task was used that required the child to communicate a choice of one or two objects on a shelf. Comparison training taught the children to select the appropriate object when paired with a similar but inappropriate object. Message training taught the children to communicate by pointing and/or gesturing. Results indicated that combined comparison and message training produced higher communication accuracy than did comparison training alone. Comparison training, however, increased subjects' accuracy of communicating as compared to an untrained control group. A parallel pattern of results was found for communication frequency. The training groups either maintained or improved their communicative performance in a near-generalization task, suggesting that they learned communicative behavior and not merely task-specific behavior.

Developmental progressions and regressions in the selective remembering strategies of EMR individuals

Developmental changes in the use of strategies to eliminate interference from irrelevant information in memory were investigated. The participants in the first experiment were 11-, 15-, and 18-year-old EMR students, and those in the second experiment were 30-year-old retarded and nonretarded adults. In both experiments a directed forgetting paradigm was used in which the person was presented two sets of pictures but only recalled one set on a trial. On some trials there was a cue to forget the first set and to remember only the second set. The cue to forget was not used by the youngest group of students. The 15- and 18-year-olds used the cue, but interference from the to-be-forgotten items remained. The 30-year-old retarded group regressed to the performance pattern of the youngest group, whereas the nonretarded adults used appropriate selective remembering strategies. The implications of developmental changes in the memory performance of retarded persons were discussed.

The effect of communicative demands on request-making in the moderately and severely mentally retarded

Two experiments were reported investigating the conditions that elicit request-making in the moderately and the severely mentally retarded. In both experiments single-subject designs were used with a store game task designed to closely approximate a naturalistic communication situation. In the first experiment moderately retarded adults were able to consistently communicate which of two objects they wished to obtain from a store counter. In the second, severely retarded adolescents initially made some errors but communicated effectively on 100% of the trials by the end of the experiment. These results contrast markedly with the results from the less naturalistic task used previously. In both experiments the amount of verbalization was greater when the task was arranged to create a demand for communication. Applications of these findings to everyday communicative situations involving the mentally retarded are discussed.