Browsing by Author "Sertic, Jacquelyn"
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Item Ankle position sense acuity does not decline in physically active older adults(2023) Sertic, Jacquelyn; Konczak, JürgenAnkle proprioception is essential for balance control. However, ankle proprioception can decline in older adulthood and has been linked to a higher incidence of falls. This study examined whether physically active older adults are spared from such proprioceptive decline. Using the Ankle Proprioceptive Acuity System (APAS) and applying an adaptive psychophysical testing paradigm, ankle position sense acuity in 57 neurotypical middle-aged and older adults (50-80 years) and 14 young adults (18-30 years) was assessed. A participants’ unloaded foot was passively rotated from a neutral joint position to a reference (15 or 25 deg plantarflexion) and a comparison position (< reference). Participants verbally indicated which position was further from neutral. Appropriate stimulus-response functions were fitted and Just-Noticeable-Difference (JND) thresholds and Uncertainty Areas (UA) were derived. The JND threshold is a measure of perceptual bias, while UA is a measure of precision. The main finding of the study: Between the middle-aged and older adult groups (50-60, 60-70, 70-80 years) no significant differences were found in JND threshold nor UA. These data indicate that active older adults may be spared from age-related decline in ankle position sense. These findings encourage older adults to become or remain active during aging.Item Characterization of Ankle Proprioception in Healthy Older Adults(2021) Fall, Nicole; Sertic, Jacquelyn; Konczak, JürgenThis study aimed to establish a typical dataset of ankle proprioception in a healthy aging population. Proprioception is the awareness of the body in space. Proprioception at the ankle joint is particularly important for balance and gait. When proprioception is compromised from neurological disorders (i.e. Parkinson's disease), these motor functions are impaired. There is no established dataset of ankle proprioception in a healthy aging population. Characterizing ankle proprioception will allow clinicians to monitor disease progression and researchers to monitor treatment efficacy in people with proprioceptive impairment. The Ankle Proprioceptive Acuity System (APAS) device was used to quantify ankle proprioception with a sensitivity of 0.1°. Participants were put through a number of trials that consisted of moving the foot to two different positions within the APAS. The participant then answered, “In which position, the first or the second, were your toes closer to the floor?” Further analysis revealed ankle proprioception was similar between age groups for all measures of acuity with mean values of proprioceptive acuity nearly identical. It was concluded that age does not contribute to a decline in ankle proprioception up until the age of 79 years. The completed data collection allowed for the establishment of a control group. In future work, this control dataset will be compared to individuals with Parkinson’s disease. Identifying trends in ankle proprioception are important in diagnosis, treatment monitoring, and determining the efficacy of interventions aimed at improving proprioception.Item Comparison of Manual and Robotic Proprioceptive Acuity Systems(2022-04-30) Fall, Nicole; Sertic, Jacquelyn; Huang, Qiyin; Konczak, JürgenAwareness of the spatial position of our body and limbs, known as proprioception, is important for bodily function and motor operation. Particularly at the ankle joint, motor skills such as balance, walking, and coordination rely on intact ankle proprioception. Without a fully-functional proprioceptive system, quality of life declines as individuals find greater difficulty completing simple and coordinated, everyday physical tasks and actions. A number of different factors can lead to proprioceptive impairment, including brain injury, developmental disorder, and neurological diseases. These include stroke, cerebral palsy, diabetic neuropathy, and Parkinson’s disease. Many ways to measure proprioceptive acuity exist and can vary based on measurement outcomes, study aims, and participant demographics. Our study constructed two ankle proprioceptive acuity systems (APAS), one manual and one robotic. This was done to examine whether the same participant would demonstrate similar ankle position sense values when applying the same psychophysical paradigms across two different devices. We hypothesized that within subjects, ankle position sense acuity would not vary significantly between the two systems. A sample of 14 healthy, neurologically unimpaired individuals (age range 19-27 years) were recruited. Participants’ right ankles were tested for ankle position sense acuity using the two systems. This allowed for identification of the just noticeable difference (JND) threshold, defined as the angle for which the participant had a 75% correct answer response rate. Participants were also measured regarding their precision, or the area of uncertainty one has about the JND threshold. Results revealed that the JND threshold was statistically significantly different (p < 0.001) between the manual and robotic APAS systems. However, precision was not statistically significantly different between the two devices (p = 0.95). Given the significant difference in JND threshold outcomes, we recommend one system be used uniformly in future studies. Using both manual and robotic APAS systems simultaneously in a single study may result in confounding measurement error. With a control population collected and a strong understanding of the differences between the two APAS systems, we are prepared to continue research studies that further our understanding of the proprioceptive sense.Item Proprioception in aging: Effects of a healthy active lifestyle and Parkinson’s disease on ankle position sense(2024-05) Sertic, JacquelynIntroduction: Proprioceptive afferents are processed at multiple levels of the central nervous system and give rise to the conscious perception of body and limb position (i.e. the proprioceptive sense) and unconscious regulation of muscle tone. Proprioceptive function declines in typical aging. This cumulative dissertation concerns the proprioceptive sense in two neurologically polar aging populations: healthy active adults (Project 1) and people with Parkinson’s disease (PD, Project 2). Project 1: Emerging evidence indicates that physical activity may spare older adults from age-related proprioceptive decline. However, the role of physical activity in preserving position sense at the ankle was unknown, in part because objective and precise measures of ankle proprioception have not been available. Aim 1: Determine the influence of a physically active lifestyle on ankle position sense acuity in healthy aging adults. Methods: This study applied sensory psychophysics to obtain a just-noticeable-difference (JND) threshold and Uncertainty Area (UA) as measures of ankle position sense acuity in young, middle-aged, and older adults. Participants were tested at two reference positions, 15° and 25°. Results: At the 15° reference, younger adults had smaller JND thresholds than both older groups (χ2(2) = 7.953, p = 0.019, η2 = 0.048). The effect size was small as 74% and 71% of middle-aged and older adults, respectively, had thresholds within the range of controls. No differences between groups were found for JND threshold at the 25° reference position nor for UA at either reference position. Only a subset of participants adhered to Weber’s law (young adults: 81%, middle-aged: 67%, older adults: 52%), which is a principle in psychophysics stating that the JND threshold is proportional to the magnitude of the stimulus. Project 2: Parkinson’s disease alters the processing of proprioceptive information resulting in impaired limb proprioception and increased muscle rigidity. Research has not firmly established that ankle proprioception is systematically impaired in people with PD, nor has the relationship been delineated between ankle proprioception and muscle rigidity. Aim 2a: Determine the extent to which ankle position sense is impaired in people with mild-to-moderate PD. Aim 2b: Examine the relationship between ankle position sense acuity and lower extremity rigidity in mild-to-moderate PD. Methods: Using the same methods established in Project 1, JND threshold and UA were obtained as measures of ankle position sense acuity in people with mild-to-moderate PD and age-matched controls. The MDS-UPDRS was used to obtain a clinical impression of rigidity. The more affected leg was assessed for both ankle position sense acuity and rigidity in people with PD. Results: Median ankle position sense JND threshold and UA were significantly larger in the Parkinsonian group than controls (JND threshold: z = 66, p = 0.020, r = 0.413; UA: z = 68.5, p = 0.044, r = 0.366). Yet, 62.5% and 80% of participants with PD had JND thresholds and UA values, respectively, within the range of the controls. JND threshold correlated with lower extremity rigidity (ρ = 0.50, p = 0.047). Disease duration was moderately correlated with JND threshold (r = 0.52, p = 0.039) and the clinical assessment of rigidity (ρ = 0.57, p = 0.020). JND threshold also correlated moderately with levodopa equivalent dosage (r = 0.54, p = 0.03). Discussion and conclusion: This dissertation challenges prevailing assumptions about ankle proprioceptive decline in aging, demonstrating that a habitually active lifestyle can preserve ankle proprioceptive function. In contrast, people with PD showed evidence of impaired position sense. Importantly, proprioceptive decline was associated with Parkinsonian muscle rigidity, establishing for the first time, a link between abnormal proprioceptive perception and abnormal control of muscle tone.Item Proprioceptive training is effective in improving movement and motor dysfunction: A Systematic Review(2022) Winter, Viola; Huang, Qiyin; Sertic, Jacquelyn; Konczak, Jürgen