Intraindividual Stepping Reaction Time Variability Predicts Falls in Older Adults With Mild Cognitive Impairment

Bunce, David; Haynes, Becky I.; Lord, Stephen R.; Gschwind, Yves J.; Kochan, Nicole A.; Reppermund, Simone; Brodaty, Henry; Sachdev, Perminder S.; Delbaere, Kim

doi:10.1093/gerona/glw164

Cited by 14 publications

(21 citation statements)

References 40 publications

(44 reference statements)

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“…As some evidence from the study of mild cognitive impairment [88,89] indicates that individuals with slower RT or raised IIV are at greater risk of disease progression, one can speculate that SIVCI patients with particularly slow RT or high IIV, are those most at risk of disease progression, or are, in fact, at a later stage of disease than that indicated by neuropsychological and other test results. Moreover, although both RT and IIV appear similarly able to differentiate SIVCI from CH, the greater association of IIV with health and functional status [47,48,50,54,[57][58][59], indicates that IIV may be a more sensitive or meaningful characteristic of VCI than RT alone, and should therefore be measured alongside RT in clinical practice. Again, further research is required to appropriately investigate such speculation.…”

Section: Reaction Time and Intraindividual Variabilitymentioning

confidence: 99%

“…Although the underlying cause for this pattern of results remains to be determined, they indicate that improvement in RT can in fact mask an abnormally high degree of IIV. Because IIV appears more related to disease, function, and health than RT [47,48,50,54,[57][58][59], its status may therefore (with further investigation) represent a more meaningful, relevant disease characteristic than RT in SIVCI.…”

Section: Practice Effectsmentioning

confidence: 99%

“…IIV is a behavioral representation of the transient fluctuation of RT over a given number of trials related to various aspects of information processing. These include (but are not limited to) attentional control and lapses, stimulus-and post-perceptual-processes and strategies, the functional and structural integrity of white and grey matter, and the status of distributed neural, and neurobiological networks [26,27,[42][43][44][45][46][47][48][49][50][51][52][53][54]. Although RT and IIV can correlate (i.e., slower RT associated with greater IIV), thus appearing to share common networks, the relationship between them is not always linear.…”

Section: Intra-individual Variability Of Reaction Timementioning

confidence: 99%

“…In an original approach, the relationship between RT and IIV in SIVCI is also examined in this study. Furthermore, IIV appears to be particularly representative of everyday functioning, cognitive status, the risk of falls, injury, health, decline in cognitive function, impending decline, lower functionality, morbidity, and mortality [47,48,50,54,[57][58][59]. Arguably therefore, IIV may be a more sensitive or meaningful marker of SIVCI than RT alone, and one which may help to improve the functional and clinical characterization of SIVCI.…”

Section: Intra-individual Variability Of Reaction Timementioning

confidence: 99%

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Subcortical Ischemic Vascular Cognitive Impairment: Insights from Reaction Time Measures

Richards

Bayer

Tree

et al. 2019

JAD

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In this study, reaction time (RT), intraindividual variability (IIV), and errors, and the effects of practice and processing load upon such function, were compared in patients with subcortical ischemic vascular cognitive impairment (SIVCI) [n = 27] and cognitively healthy older adults (CH) [n = 26]. Compared to CH aging, SIVCI was characterized by a profile of significantly slowed RT, raised IIV, and higher error levels, particularly in the presence of distracting stimuli, indicating that the integrity and/or accessibility of the additional functions required to support high processing load, serial search strategies, are reduced in SIVCI. Furthermore, although practice speeded RT in SIVCI, unlike CH, practice did not lead to an improvement in IIV. This indicates that improvement in RT in SIVCI can in fact mask an abnormally high degree of IIV. Because IIV appears more related to disease, function, and health than RT, its status and potential for change may represent a particularly meaningful, and relevant, disease characteristic of SIVCI. Finally, a high level of within-group variation in the above measures was another characteristic of SIVCI, with such processing heterogeneity in patients with ostensibly the same diagnosis, possibly related to individual variation in pathological load. Detailed measurement of RT, IIV, errors, and practice effects therefore reveal a degree of functional impairment in brain processing not apparent by measuring RT in isolation.

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Section: Reaction Time and Intraindividual Variabilitymentioning

confidence: 99%

Section: Practice Effectsmentioning

confidence: 99%

Section: Intra-individual Variability Of Reaction Timementioning

confidence: 99%

Section: Intra-individual Variability Of Reaction Timementioning

confidence: 99%

See 2 more Smart Citations

Subcortical Ischemic Vascular Cognitive Impairment: Insights from Reaction Time Measures

Richards

Bayer

Tree

et al. 2019

JAD

View full text Add to dashboard Cite

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“…There is growing evidence that, in addition to the decline in various physiological functions, older individuals become more variable in their movement output (Bielak, Cherbuin, Bunce, & Anstey, 2014;Bielak, Hultsch, Strauss, MacDonald, & Hunter, 2010;Bunce et al, 2017;Bunce, MacDonald, & Hultsch, 2004). Indeed, there is an increasing recognition that the pattern of variability over successive trials within a single person (i.e., intraindividual variability) reveals important organizational features of the neuromotor system and its output that can be distinct from the mean of a given variable and the degree of variability between persons (i.e., interindividual variability) (Newell & Corcos, 1993;Newell & Slifkin, 1998).…”

Section: Introductionmentioning

confidence: 99%

Intraindividual Variability of Neuromotor Function Predicts Falls Risk in Older Adults and those with Type 2 Diabetes

Morrison

Newell

2018

Journal of Motor Behavior

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This study was designed to examine the effect of increasing age and type 2 diabetes on the average responses and inter- and intraindividual variability of falls risk, reaction time, strength, and walking speed for healthy older adults and older persons with type 2 diabetes (T2DM). Seventy-five older individuals (controls) and 75 persons with T2DM aged between 50 and 79 years participated in the study. Assessments of falls risk, reaction time (RT), knee extension strength, and walking speed were conducted. The results revealed that advancing age for both control and T2DM groups was reflected by a progressive increase in falls risk, decreased leg strength and a decline (i.e., slowing) of reactions and gait speed. Conversely, the level of intraindividual variability for the RT, strength and gait measures increased with increasing age for both groups, with T2DM persons tending to be more variable compared to the healthy controls of similar age. In contrast to the intraindividual changes, measures of interindividual variability revealed few differences between the healthy elderly and T2DM individuals. Taken together, the findings support the proposition that intraindividual variability of neuromotor measures may be useful as a biomarker for the early detection of decline in physiological function due to age or disease.

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Neuromotor and cognitive responses of adults with autism spectrum disorder compared to neurotypical adults

et al. 2018

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Autism spectrum disorder (ASD) is a common neurodevelopmental disorder, whose core symptom domains include impaired social communication and narrowed interests and/or repetitive behaviors; in addition, deficits of general cognition, neuromotor function, and movement ability can be observed. This study was designed to examine differences in neuromotor and cognitive functions for a group of young adults with ASD and age-matched controls. It was also of interest to assess whether changes in the intra-individual variability (IIV) of these selected neuromotor and cognitive tasks also occurred. Increased IIV in persons with ASD may reveal important organizational features of their neuromotor system that differ from neurotypical controls. Twenty neurotypical adult individuals (24.3 ± 2.8 years) and twenty adults with a clinician-assigned diagnosis of ASD (21.2 ± 4.4 years) participated in this study. Specific cognitive and motor assessments included Trails Making Tests A&B, Symbol Digit Modalities Test, Purdue Pegboard Test, simple reaction time, finger tapping, hand grip strength, balance, and gait. Results revealed that the ASD adults exhibited decreased upper limb strength and slower responses for finger tapping, hand dexterity, reaction times, and gait compared to the non-ASD controls. The general slowing of motor responses for the persons with ASD was also associated with increased within-subject variability during the reaction time, finger tapping, hand grip, and gait assessments compared to neurotypical adults, illustrating that IIV measures may be a useful marker of widespread neuromotor dysfunction for adults with ASD. Overall, these findings are consistent with clinical observations that abnormalities of movement performance and cognitive performance are an associated feature of ASD in young adults.

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Intraindividual Stepping Reaction Time Variability Predicts Falls in Older Adults With Mild Cognitive Impairment

Cited by 14 publications

References 40 publications

Subcortical Ischemic Vascular Cognitive Impairment: Insights from Reaction Time Measures

Subcortical Ischemic Vascular Cognitive Impairment: Insights from Reaction Time Measures

Intraindividual Variability of Neuromotor Function Predicts Falls Risk in Older Adults and those with Type 2 Diabetes

Neuromotor and cognitive responses of adults with autism spectrum disorder compared to neurotypical adults

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