Dual-Task Costs in Gait Speed Differs Across Age Groups

With age, there are simultaneous reductions in gait speed (GS). This decrease in GS has been associated with an increased fall risk and negatively impacts independence. Further, GS naturally declines with the addition of a secondary stimulus (i.e., cognitive requirements). Combined, these decrements can be additive in nature potentially leading to robust declines with advancing age. Therefore, the aim of this study was to examine age-related effects of dual-task cost (DTC) while walking. Adults (N = 145), over the age of 45 years, completed two walking trials for each GS condition: habitual (HAB) and fast (FST), with and without a DT (i.e., counting backwards by serials of three). Subjects were classified into four age groups: youngest-old (YG ≤ 64 years, n = 24), young-old (YO, 65-74 years, n = 46), middle-old (MO = 75-84 years, n = 54), and oldest-old (OO ≥ 85 years, n = 21). DTC was calculated and ANOVAs were used to assess differences between the groups. There was no difference in HAB DTC between the age groups (p=.61). However, there was a significant difference in FST DTC (p=.04) between the YO (M±SD: -14 ± -11%) and OO (M±SD: -24 ± -12%). These data indicate there was an age-related affect for fast dual-task cost, but not for habitual dual-task cost while walking. An increase in dual-task cost among the oldest-old may be associated with an inability to properly maintain a faster cadence while performing an arithmetic task which may be related to task prioritization.

Walking While Talking and Prefrontal Oxygenation in Motoric Cognitive Risk Syndrome: Clinical and Pathophysiological Aspects

Background: Motoric cognitive risk syndrome (MCR) combines slow gait and cognitive complaints and has been proposed as a predementia syndrome. The nature of dual-task performance in MCR has not been established. Objective: To assess differences in dual-task performance between participants with and without MCR and to study the prefrontal cortex (PFC)-based brain activity during dual-task using functional near-infrared spectroscopy. Methods: Cohort study of community-dwelling non-demented older adults included in the “Central Control of Mobility in Aging” study. Comprehensive assessment included global cognition and executive function tests along with clinical variables. Dual-task paradigm consisted in walking while reciting alternate letters of the alphabet (WWT) on an electronic walkway. We compared dual-task performance between MCR (n = 60) and No MCR (n = 478) participants and assessed the relationship of dual-task performance with cognitive function. In a subsample, we compared PFC oxygenation during WWT between MCR (n = 32) and No MCR (n = 293). Results: In our sample of 538 high-functioning older adults (76.6±6.5 years), with 11.2% prevalence of MCR, dual-task cost was not significantly different, compared to No MCR participants. Among MCR participants, no significant relationship was found between WWT velocity and cognitive function, whereas No MCR participants with better cognitive function showed faster WWT velocities. PFC oxygenation during WWT was higher in MCR compared to No MCR (1.02±1.25 versus 0.66±0.83, p = 0.03). Conclusion: MCR participants showed no significant differences in the dual-task cost while exhibiting higher PFC oxygenation during dual-task walking. The dual-task performance (WWT velocity) in MCR participants was not related to cognition.

Dual task gait deteriorates gait performance in cervical dystonia patients: a pilot study

Day-to-day walking-related activities frequently involve the simultaneous performance of two or more tasks (i.e., dual task). Dual task ability is influenced by higher order cognitive and cortical control mechanisms. Recently, it has been shown that the concomitant execution of an attention-demanding task affected postural control in subject with cervical dystonia (CD). However, no study has investigated whether dual tasking might deteriorate gait performance in CD patients. To investigate whether adding a concomitant motor and cognitive tasks could affect walking performance in CD subjects.17 CD patients and 19 healthy subjects (HS) participated in this pilot case–control study. Gait performance was evaluated during four walking tasks: usual, fast, cognitive dual task and obstacle negotiation. Spatiotemporal parameters, dual-task cost and coefficients of variability (CV%) were measured by GaitRite® and were used to detect differences between groups. Balance performance was also assessed with Mini-BEST and Four Step Square tests. In CD participants, correlation analysis was computed between gait parameters and clinical data. Significant differences in complex gait and balance performance were found between groups. CD patients showed lower speed, longer stance time and higher CV% and dual-task cost compared to HS. In CD, altered gait parameters correlated with balance performance and were not associated with clinical features of CD. Our findings suggest that complex walking performance is impaired in patients with CD and that balance and gait deficits might be related

Functional capacity and dual-task cost in the institutionalized older adults, both affected and unaffected by mild cognitive impairment

Background Mild cognitive impairment (MCI) affects 10–20% of the individuals over the age of 65; this proportion being higher in the institutional care facilities than within a general population. Aim To assess whether dual-task cost in the individuals affected by MCI depends exclusively on gait, or possibly some other functional capacity components might also come into play, as compared to the healthy controls also remaining in the institutional care. Methods The study was conducted in five nursing facilities, involving 88 subjects in total, i.e. 44 subjects affected by MCI (mean age of 83.8 years; 34 women (77.3%) and 10 men (22.7%), and 44 healthy controls (mean age 81.67 years; 38 women (84.4%) and 7 men (15.6%). Cognitive functions were assessed through Mini–Mental State Examination (MMSE), while gait by Timed Up and Go Test (TUGT). Gait speed was calculated by the 10 Meter Walk Test, and the fear of falling with the Falls Efficacy Scale International. Dual tasks were assessed by TUGTMAN (Timed Up and Go Test Manual) and TUGCOG (Timed Up and Go Test Cognitive). Dual Task Cost (DTC) of TUGTMAN and TUGTCOG was established. Statistical analyses were completed with STATISTICA Package v. 10. Results Individuals affected by MCI differed significantly from the unaffected ones with regard to their gait test results, when assigned a single-task activity, and dual-task activities, as well as in the gait speed. Dual Task Cost Manual (DTCMAN) in the MCI group was significantly higher, as compared to the subjects unaffected by MCI. Around 25% of the variance of DTCMAN result regarding the MCI group was accounted for by gait performance in the single-task conditions (TUGT). In the case of Dual Task Cost Cognitive (DTCCOG), this value equalled to approx. 10%. A 1% change in DTCMAN corresponded to approx. 0.5 s change in TUGT, whereas a 1% change in DTCCOG entailed approx. 0.35 s change in TUGT walking time. Conclusion Individual functional capacity affected the dual-task performance, especially the motor-motor tasks. Dual-task cost in the subjects affected by MCI was significantly reduced, being more dependent on the gait speed in the motor-motor tasks, which entailed visual memory, than in the motor-cognitive tasks.

EXPRESS: Attention in Post-Lexical Processes of Utterance Production: Dual-Task Cost in Younger and Older Adults

There is a general agreement that speaking requires attention at least for conceptual and lexical processes of utterance production. However, conflicting results have been obtained with dual-task paradigms using either repetition tasks or more generally tasks involving limited loading of lexical selection. This study aimed to investigate whether post-lexical processes recruit attentional resources. We used a new dual-task paradigm in a set of experiments where a continuous verbal production task involved either high or low demand on lexical selection processes. Experiment 1 evaluates lexical and post-lexical processes with a semantic verbal fluency task, whereas experiments 2 and 3 focus on post-lexical processes with a non-propositional speech task. In each experiment, two types of non-verbal secondary tasks were used: processing speed (simple manual reaction times) or inhibition (Go/No-go). In Experiment 1, a dual-task cost was observed on the semantic verbal fluency task and each non-verbal task. In Experiment 2, a dual-task cost appeared on the non-verbal tasks but not on the speech task. The same paradigm was used with older adults (Experiment 3), as increased effort in post-lexical processes has been associated with ageing. For older adults, a dual-task cost was also observed on the non-propositional verbal task when speech was produced with the inhibition non-verbal task. The results suggest an attentional cost on post-lexical processes and strategic effects in the resolution of the dual-task.