Trunk muscle performance in early Parkinson's disease.

BACKGROUND AND PURPOSE: Altered trunk function has been observed in people with Parkinson's disease (PD). SUBJECTS: This study investigated the trunk function of people with PD, as compared with people without PD. METHODS: Range of motion (against 1 N.m of resistance), isometric torque, and isoinertial performance against moderate resistance were assessed using an Isostation B-200. RESULTS: Group effects between the subjects with PD and the subjects without PD were found for all variables. Range of motion into extension and maximum and average isometric torque in the directions of extension and right rotation showed group effects between subjects classified as being in Hoehn and Yahr stage I and subjects classified as being in Hoehn and Yahr stage II. CONCLUSION AND DISCUSSION: People with PD exhibit less axial range of motion and isometric and isoinertial ability compared with persons without PD. There is a loss of the ability to extend the trunk early in the disease. These findings suggest the importance of further investigation into the role of strengthening programs soon after a diagnosis of PD in order to potentially delay changes in trunk function and subsequent functional difficulties.

Outcomes 5 years post-traumatic brain injury (with further reference to neurophysical impairment and disability).

The assessment of recovery and outcomes post-traumatic brain injury (TBI) has often been poorly researched and reported in past literature. Indeed, an accurate documentation of outcomes in this population had never been performed in the state of South Australia. To redress this situation this study collected data on people who had sustained a TBI 5 years previously, using medical records, personal interview/questionnaire and neurophysical assessment in order to investigate broad outcomes as well as the specific nature and prevalence of any residual physical impairment and disability. The results (n = 67) indicate that the subjects' living arrangements had not altered significantly, and nearly half had returned to some form of paid work, though over 50% were reliant on the welfare system. The majority (57%) felt they had improved in all areas, 19% partially improved and 8% felt they had actually deteriorated. Considering the physical data, the most frequent areas of residual impairment were headaches, followed by balance difficulties and fatigue/weakness. Functionally, 30% had some degree of deficit in upper limb activity and 9% required assistance for particular transfer tasks. Overall balance was impaired in 34% and gait was altered in 24% with 9% reliant on wheelchairs for mobility. Such data may be used in the education of people with TBI and those who live and/or work with them, as well as in future studies assessing the impact of various factors on recovery and outcomes. Evidence was also provided that residual physical issues should be considered along with the more researched areas of cognition and psychosocial issues.

Is there a divided attention deficit in patients with early Parkinson's disease?

Divided attention was studied in a group of patients with early Parkinson's disease and compared to normal controls matched for age, gender and intellectual status using a dichotic monitoring task. The Parkinson patients had more difficulty dividing their attention between two competing auditory inputs than the normal subjects. This impairment in divided attention or general attentiveness may be due to changes in the ascending monoamine projections, which have been shown to have a role in auditory attention. A right ear advantage (REA) was also observed. Not only were speech messages discriminated better by the right than the left ear, but these messages were processed more quickly by the right ear.

Bilateral femoral rotations measured during walking: a new parameter to summarize and describe individual gait.

The aim of this study was to develop and assess a method of analysis of femoral rotations to describe and summarize an individual's gait. Twelve normal subjects underwent walking trials at both natural and slow speeds, controlled by a metronome. The three-dimensional rotations of each femur were measured, simultaneously, during walking using a 3SPACE Tracker. The phase lags between the three rotations for each leg, obtained by cross-correlations, provided the primary data. The device was found to be reliable and gave significant test--retest repeatability. The analyses provided summary parameters describing mathematically the patterns of rotations and showed there was repeatability within and between sessions. A strong systematic subject effect in all analyses indicated that these parameters provide a highly specific description of how an individual walks.

The reliability of postural sway measures using the 3SPACE Tracker.

OBJECTIVE: To investigate the reliability of three-dimensional postural control sway measures, in a normal population, using an electromagnetic device. DESIGN: A repeated measures design was used within and between sessions. BACKGROUND: Electromagnetic measurement has been proposed as a method of measuring postural sway; however, reliability within a normal population has not been shown. METHOD: An electromagnetic device, the 3SPACE Tracker, measured postural sway at the pelvis using sway path length and displacements in the anterior-posterior, medial-lateral and vertical direction. Ten subjects performed a postural control task involving two trials for six different sensory conditions, on two separate occasions, two weeks apart. RESULTS: The reliability of the technique was demonstrated by the repeatability of results for individual subjects within and between sessions. Individual subjects and sensory conditions were discriminated. Sway path length was the most consistent of the measures used. CONCLUSIONS: Three dimensional measures of postural sway are reliable and discriminatory in a normal population.

Position sense at the elbow after fatiguing contractions.

Fatigue is often associated with increased clumsiness. One possible explanation for this is that the proprioceptive signals from receptors in and around muscles change during muscle fatigue. Thirteen human subjects were tested for their ability to match the elbow angle of one arm with the contralateral arm, before and after a fatiguing contraction of one arm. Contractile fatigue was induced by a series of maximal voluntary contractions of the elbow flexors of the dominant arm. While fatigue of either the target arm or the matching arm usually changed the ability of individual subjects to match arm position, this effect varied markedly from one subject to another and no consistent pattern was discerned. In particular, there was no reciprocal change when the fatigued arm was the matching arm compared with when the nonfatigued arm was the matching arm. The absence of a consistent reciprocal effect indicates that the fatigue-related changes in the ability to match arm position are not solely due to changes in proprioceptive signals and that central fatigue processes are probably involved.

Auditory attention in early Parkinson's disease: an impairment in focused attention.

Focused attention in the auditory modality was studied in a group of Parkinson patients and compared to matched controls using a Dichotic monitoring task. Parkinson patients detected more phonemic distractors on the unattended input than the normal controls, despite a high level of ipsilateral responses for target detection and target discrimination. This impairment in focused attention may be attributed to degenerative changes in the ascending monoamine pathways which have been implicated in the role of auditory attention.

Patients with early Parkinson's disease are not impaired on spatial orientating of attention.

The shifting of attention to visual stimuli was studied in twenty patients with early Parkinson's disease (stage I or II as defined by the Hoehn and Yahr scale) and twenty normal controls matched for age, sex and intellectual status. Both groups were screened to exclude dementia, psychiatric disease and other neurological abnormalities. The speed of shifting attention to visual stimuli was measured using the cost and benefit paradigm. The results showed an overall increase in response latencies in patients with early Parkinson's disease compared to the Control group, but without a concomitant slowness to shift their attention toward a visual spatial target. This slowness which appears to reflect a delay in the decision-making process, regardless of the demands of the task, was independent of motor impairment, mood, intellectual status and Levodopa medication. While the Parkinson patients and normal controls showed a 38 msec benefit when the target stimulus was expected in a given location, all subjects failed to demonstrate a cost when the target stimulus was presented in an unexpected location. This may be a reflection of age. Alternatively, subjects may have learned to inhibit responses to the invalid cue.

Distractibility in early Parkinson's disease.

Post-mortem evidence has shown a depletion of dopamine in the mesocortical and mesolimbic pathways in brains of Parkinson patients. Since these dopaminergic pathways have been implicated in the control of attention in animals, selective attention to visual stimuli was studied in eight patients with early Parkinson's disease (Stage I or II as defined by the Hoehn and Yahr Scale) and eight normal controls of comparable age, sex and Full Scale Intelligence Quotient. Subjects with dementia, psychiatric disease and other neurological abnormalities were excluded. The Parkinson patients were more prone to interference in the presence of distractor items than the normal controls as shown on the focussing + distraction and switching + distraction of attention paradigms on the Distractor task. There findings are not accounted for by mood, intellectual status or memory and thus may be as a result of the loss of dopamine in the mesocortico-limbic projections.

Motor planning in Parkinson patients.

This study was designed to determine if Parkinsonian patients exhibited a deficit in motor planning. Thirty adult males, 15 with Parkinson's disease and 15 normal controls, were given a gestural test which had two components. The first component required the symbolic representation of implement usage on verbal command and on imitation (representational items) and the second component required the imitation of non-symbolic hand positions (non-representational items). The results indicated that Parkinsonian patients performed at a significantly lower gestural level on the representational tasks and made significantly more spatial errors on non-representational tasks than the normal controls.