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Biomedical subjects

R P Di Fabio

Publications and source records attributed to R P Di Fabio.

At least 19 recordsLinked to original sources
PubMed2001

Suppression of the vertical vestibulo-ocular reflex in older persons at risk of falling.

A case-control design was used to assess eye-head-trunk coordination for community-dwelling elders performing a stand-walk task. Eighteen elders with a high risk of falling were matched to 18 subjects with low risk on the basis of age, living status (living alone or with someone) and category of residence (independent living or assisted living facility). Standard electro-oculography was used in conjunction with an electromagnetic tracking device to measure eye and head-trunk motion, respectively. For the low-risk group, the mean slope of gaze-head and gaze-trunk relationships was significantly greater than zero (0.91 and 0.64, respectively), whereas high-risk elders did not demonstrate slope magnitudes significantly different from zero (0.52 and 0.16, respectively) due to large inter-subject variations. While the majority of subjects showed some counter-rotation of the eyes with head pitch, a greater percentage of subjects in the high-risk group did not suppress this response and consequently gaze and gaze velocity overcompensated for head pitch. These findings suggest that the vertical vestibulo-ocular reflex is not adequately suppressed during the stand-walk task in elders who are at a high risk of falling. Possible mechanisms contributing to these findings are discussed.

Accidental Falls↗
PubMed2001

Evaluating eye-body coordination during unrestrained functional activity in older persons.

BACKGROUND: Traditional paradigms for the study of ocular-motor control restrain subject motion and have not adequately quantified the sensorimotor strategies used by older persons to control gaze while performing activities of daily living. The purpose of our study was to describe eye-head-trunk coordination during a functional activity in freely moving community-dwelling older persons. METHODS: Thirty-five community-dwelling older persons (age range 71-92 years) participated in this study. Surface electro-oculography was used with an electromagnetic tracking device to measure vertical eye movement and linear and angular head position while each subject performed a stand-from-chair task. RESULTS: Standing from a chair involved low-frequency head motion (median z = 0.25 Hz; median pitch = 0.32 Hz). The distribution of phase for eyes versus vertical body motion were skewed toward head-trunk leading, suggesting that eye motion follows vertical body motion. Vertical gaze, however, was in phase with and moved in the same direction as head pitch. CONCLUSIONS: Gaze (eye position in space) was an active, integrated component of the standing motion. The results imply that both the oculomotor system and the head motor system in older persons are coordinated to direct gaze and, when necessary, work to suppress the vestibuloocular reflex. The interaction of eye-head-trunk motion provides a basis for understanding how a breakdown in the gaze control mechanisms in older persons might contribute to the risk of falling and fall-related injuries.

Aged↗
PubMed2001

Follow the eyes.

Explore the source record for details and available documents.

Dominance, Ocular↗
PubMed2001

Effect of aerobic exercise on tracking performance in elderly people: a pilot study.

BACKGROUND AND PURPOSE: Although much is known about the benefits of aerobic exercise on cardiovascular health, little research has been done on the effect of aerobic exercise on motor performance. This study examined whether aerobic exercise has an effect on visuospatial information processing during finger-movement tracking in elderly subjects. SUBJECTS: Fifteen elderly subjects (mean age=83.2 years, SD=5.7, range=72-91) from a senior housing complex were randomly assigned to a control group or an experimental (exercise) group. Twelve subjects completed the study, and data obtained for 10 subjects were used for data analysis (2 control subjects were eliminated to allow for matched-pairs analysis between the experimental and control groups). The control group (n=5) had a mean age of 80.2 years (SD=7.8). Subjects in the experimental group (n=5) had a mean age of 84.8 years (SD=2.5). METHODS: The intervention consisted of group exercise 3 times a week for 8 consecutive weeks, and included calisthenics (eg, marching in place, side stepping, mock boxing), stationary bicycling, and walking. A finger-movement tracking test and submaximal graded exercise tolerance step tests were performed before and after training to determine changes in finger-movement tracking and any aerobic training effects. RESULTS: Matched-pairs t tests showed a difference in tracking from pretest to posttest in the experimental group compared with the control group. Step test performance did not differ between the 2 groups. DISCUSSION AND CONCLUSION: The results of this small-scale study with a limited number of subjects indicate that, for elderly people, finger-movement tracking performance can improve with aerobic exercise, despite the absence of an aerobic training effect. Possible mechanisms for the treatment effect on information processing are discussed.

Aged↗
PubMed1999

Manipulation of the cervical spine: risks and benefits.

Manipulation of the cervical spine (MCS) is used in the treatment of people with neck pain and muscle-tension headache. The purposes of this article are to review previously reported cases in which injuries were attributed to MCS, to identify cases of injury involving treatment by physical therapists, and to describe the risks and benefits of MCS. One hundred seventy-seven published cases of injury reported in 116 articles were reviewed. The cases were published between 1925 and 1997. The most frequently reported injuries involved arterial dissection or spasm, and lesions of the brain stem. Death occurred in 32 (18%) of the cases. Physical therapists were involved in less than 2% of the cases, and no deaths have been attributed to MCS provided by physical therapists. Although the risk of injury associated with MCS appears to be small, this type of therapy has the potential to expose patients to vertebral artery damage that can be avoided with the use of mobilization (nonthrust passive movements). The literature does not demonstrate that the benefits of MCS outweigh the risks. Several recommendations for future studies and for the practice of MCS are discussed.

Cervical Vertebrae↗
PubMed1998

Tracking control in the nonparetic hand of subjects with stroke.

OBJECTIVE: To examine in subjects with stroke using their nonparetic side how different levels of stimulus-response (S-R) compatibility, which require different levels of information processing, affect manual tracking control. DESIGN: Descriptive study comparing finger movement tracking performance under S-R-compatible and S-R-incompatible conditions between subjects with stroke and healthy controls. Four two-factor analysis of variance tests with one independent factor (group, gender, laterality, or order) and one repeated measures factor (position) comprised the data analysis. SETTING: University-based research setting. PATIENTS: Forty subjects with chronic stroke: 20 right hemiplegia (average age, 65.2+/-2.3 yrs); 20 left hemiplegia (average age, 68.6+/-2.3 yrs). Fifty-one healthy controls: 24 using nondominant hand (average age, 68.6+/-2.1 yrs); 27 using dominant hand (average age, 68.7+/-2.0 yrs). All were right-handed. MAIN OUTCOME MEASURE: Tracking accuracy index (AI), based on root-mean-square error normalized to scale of each subject's tracking target. RESULTS: In S-R-incompatible condition, AI of subjects with stroke was not significantly different from controls (F[1, 89]=1.73, p=.19). In S-R-compatible condition, AI of control subjects was significantly better than subjects with stroke (F[1, 89]=14.3, p=.0003). CONCLUSION: Manual tracking is impaired in nonparetic hand of subjects with stroke, suggesting that information processing, distinctly separate from motor weakness, may be an underestimated problem impairing controlled movements in individuals with stroke.

Adult↗
PubMed1998

Extended outpatient rehabilitation: its influence on symptom frequency, fatigue, and functional status for persons with progressive multiple sclerosis.

OBJECTIVE: To determine the influence of an extended outpatient rehabilitation program on symptom frequency, fatigue, and functional status for persons with multiple sclerosis (MS). DESIGN: Nonequivalent pretest/posttest control-group design, with posttest 1 year after initial assessment. Multiple regression analysis and analysis of covariance were used to control for symptom severity at the initial assessment and comorbid factors including depression, cognitive function, and social interaction. Effect sizes (ES) provided a descriptive measure of the change in outcomes. SETTING: Outpatient multidisciplinary rehabilitation clinic. PATIENTS: Forty-six patients with definite chronic progressive MS; 20 received treatment and 26 were in a nontreatment comparison group ("waiting list"). INTERVENTION: Rehabilitation services for 5 hours, 1 day per week, over 1 year. MAIN OUTCOME MEASURES: The MS-Related Symptom Checklist composite score, fatigue frequency, and selected items from the Rehabilitation Institute of Chicago Functional Assessment Scale. RESULTS: Receiving treatment was a significant predictor of reduced symptom frequency (partial r2 = .26) at the 1-year follow-up. The ES adjusted for baseline values indicated substantial reductions in symptom frequency for the treatment group (EStreatment = .27 vs ESwaitlist = -.32). Fatigue was significantly reduced at the time of follow-up for the treatment group compared with the waiting list group (EStreatment = .46 vs ESwaitlist = -.20). There were no statistically significant differences among groups regarding functional status, but there appeared to be less loss of functional status in the treatment group compared with the waiting list group (EStreatment = -.07 vs ESwaitlist = -.70). CONCLUSIONS: An extended outpatient rehabilitation program for persons with definite progressive MS appears to effectively reduce fatigue and the severity of other symptoms associated with MS.

Adult↗