John J. Nicholas

Anticipatory postural adjustments during self inflicted and predictable perturbations in Parkinson's disease.

This study investigated the relation between impaired anticipatory postural adjustments and bradykinesia in Parkinsons disease. Patients with Parkinsons disease and age matched controls stood on a platform. In one series of experiments, they performed fast, discrete shoulder flexion or extension movements. In another series, they were required to press a trigger with the right thumb and thus to release a load that was suspended from a bar which they were holding in front of them in extended arms. One more series included catching a load on the same bar. Anticipatory changes in the activity of postural muscles before fast voluntary movements occurred in patients and controls although the patients showed higher variability of anticipatory patterns. During load dropping and catching, control subjects had reproducible, although smaller, anticipatory changes in postural muscle activity. Such changes were absent in all but one patient. Two sources of these postural perturbations were analysed. The anticipatory postural adjustments in different muscle groups may counteract perturbations of different origin. The distal to proximal sequencing of joint involvement in postural reactions may be related to different reference points and working points associated with these tasks compared with reaching limb movements. The deficit in anticipatory postural adjustments in Parkinsons disease is likely to be unrelated to bradykinesia and is more likely to reflect the deficits in the basic processes of preparation and initiation of a motor act.

Feedforward postural adjustments in a simple two-joint synergy in patients with Parkinson's disease

Patients with Parkinsons disease, age-matched controls and young control subjects performed discrete elbow or wrist movements in a sagittal plane under the instruction to move one of the joints as fast as possible. Relative stability of the other, postural joint was comparable in all 3 groups, while movement time was the highest in the patients and the lowest in young controls. Typically, EMG patterns in both muscle pairs acting at the joints demonstrated a commonly observed tri-phasic pattern. A cross-correlation analysis of the EMGs confirmed virtually simultaneous bursts in the wrist and elbow flexors and in the wrist and elbow extensors. In all 3 groups, there were no signs of anticipatory activation of postural muscles in about 90% of movements. We consider postural anticipation not a separate process, but a separate peripheral pattern of a single control process that may involve a number of joints and muscles. We conclude that the postural deficits in Parkinsons disease are not related to a basic deficit in the ability to generate feedforward postural adjustments but to other factors that may include the specificity of maintaining the vertical posture in the field of gravity.

Anticipatory postural adjustments during standing in below-the-knee amputees

OBJECTIVE: We studied the role of adaptive changes within the central nervous system in anticipatory postural adjustments seen in unilateral below-the-knee amputees. DESIGN: Changes in electromyographic and mechanical variables were compared during standardized tasks performed by standing subjects. BACKGROUND: Anticipatory postural adjustments represent an important mechanism of postural control which was expected to be changed in amputees because of both mechanical and secondary, neurological reasons. METHODS: Six patients after a below-the-knee amputation and six control subjects stood on a force platform and performed fast bilateral shoulder movements and also dropped or caught a load from (into) extended hands. Anticipatory changes in the background activity of postural muscles were analysed. RESULTS: In amputees, there were cases of marked asymmetry in anticipatory changes of the background muscle activity which were larger on the intact side of the body but were commonly small or absent on the side of the amputation. This asymmetry could lead to larger mediolateral forces and displacements of the centre of pressure. CONCLUSIONS: We suggest that asymmetrical patterns of anticipatory postural adjustments reflect central adaptive changes secondary to the amputation. Rehabilitation approaches would benefit from understanding and taking advantage of the adaptive changes within the central nervous system. RELEVANCE: We demonstrated asymmetries in patterns of anticipatory postural adjustments during voluntary arm movements and load manipulations by standing unilateral amputees. This finding is of potential importance for rehabilitation of amputees and their prosthetic training.

The quality of life after orthotopic liver transplantation: An analysis of 166 cases

We surveyed by questionnaire 346 patients who underwent orthotopic liver transplantation to determine their postoperative status. One hundred sixty-six patients returned the questionnaires, which were administered at least 12 months after the transplants. Universally, the patients could perform necessary activities of daily living, but 36.7% noted some extremity weakness, 18.1% noted pain in an extremity, and 40.4% noted arthritis. Of the respondents, 41.3% rode a bike often, 28.4% swam, and endurance improved from 43.9% severely affected to 8.0% severely affected. Posttransplant employment was related to marital status (3.18 times more likely to be employed if married); duration of liver disease with patients having the disease more than 2 years 3.22 times more likely to be employed. Patients without pain, weakness, or arthritis were 7.8 times more likely employed. The exact nature of the musculoskeletal complaints remains to be defined.

Are there deficits in anticipatory postural adjustments in Parkinson's disease?

We studied anticipatory postural adjustments in patients with Parkinsons disease who dropped a load from extended arms while standing. Anticipatory postural adjustments were seen when load dropping was induced by a fast, bilateral shoulder abduction but not when it was induced by pressing a trigger with the right thumb. We conclude that anticipatory postural adjustments in patients with Parkinsons disease can change with the magnitude of an action which is used to trigger a predictable postural perturbation. Thus, the described deficits in anticipatory postural adjustments in patients with Parkinsons disease are likely to be of quantitative rather than qualitative nature.

Problems Experienced and Perceived by Prosthetic Patients

Ninety-four patients from two amputee clinics completed a 123-item questionnaire. Results were tabulated and subjected to statistical analysis by computer. Results indicate patients feel decreased ability to defend themselves, a sense of difficulty with appearances, and perceive they did not receive rehabilitation care in transfers, tub baths, driving, etc. Tests for depression were more strongly positive in patients who most recently had undergone amputation.

Rehabilitation staff perceptions of characteristics of geriatric rehabilitation patients

OBJECTIVEnTo determine if professionals treating older rehabilitation patients regarded them as having different characteristics than younger rehabilitation patients, to derive factors from these perceptions, and to examine the impact of the discipline of the professional and other factors on these perceptions.nnnDESIGNnRehabilitation professionals at a random sample of facilities accredited by the Commission on Accreditation of Rehabilitation Facilities were surveyed to determine their level of agreement with 60 items addressing characteristics of older rehabilitation patients. The items were derived from focus groups with rehabilitation staff members.nnnPARTICIPANTSnOne thousand sixty-three rehabilitation professionals from nine disciplines (nursing, occupational therapy, physiatry, physical therapy, psychology, social work, speech pathology, therapeutic recreation, and vocational counseling) responded to the questionnaire and were included in the study.nnnRESULTSnThere was a wide range of agreement levels across the 60 items (range of median agreement, 12.7% to 93.5%). Factor analysis resulted in six categories of perceptions regarding older rehabilitation patients: (1) physical limitations, (2) motivational deficits, (3) psychological distress/need for support, (4) maturity and positive coping skills, (5) need for privacy/decreased adaptability, and (6) discharge complications. Significant differences across disciplines were found for five of six factors. Nurses agreed more strongly with the negative psychological factors (2, 3, and 5) compared to physical therapists, psychologists, and social workers. Physicians scored significantly higher than two other disciplines on the physical limitations factor. These differences may be related to the distinct role each discipline plays in the rehabilitation process. Older professionals also scored higher on four factors, likely because of personal rather than professional experience with aging.nnnCONCLUSIONSnTreating professionals recognize differences between younger and older rehabilitation patients. Many of these perceived differences can be viewed as variables that require more effort and skill on the part of the treating professional. The training of rehabilitation professionals needs to better prepare individuals from all disciplines to adapt to age-specific differences.

Naturalization of the alien hand: case report.

The alien hand syndrome is an involuntary motor phenomenon that occurs infrequently and mostly in stroke patients. A case is reported of a 67-year-old man with left hemiparesis whose hand crept and crawled, especially at night, which caused him to awaken by grasping his collar. The disturbing nocturnal activity of the hand was stilled by placing it in a common oven mitt.

Motor control research in rehabilitation medicine

Progress in rehabilitation medicine requires an understanding of the basic rules of motor coordination, as well as of the contribution of adaptive processes within the central nervous system to the patterns of impaired movements. We assume that patterns of voluntary movements reflect rules of coordination that are used by the intact central nervous system of healthy persons. In pathological conditions that may include cognitive, central neurological, and peripheral disorders, the central nervous system may reconsider these rules leading to different peripheral patterns of voluntary movements. In such conditions, changed motor patterns may be considered adaptive to a primary disorder. They may even be viewed as optimal for a given state of the system of movement production. We suggest that the emphasis of therapeutic approaches must be placed not on restoring the motor patterns to as close to normal as possible, but on assisting the central nervous system to develop optimal adaptive reactions to the original underlying problem.

Bacterial discitis caused by limb gangrene requiring below-knee amputation

Two patients presented with disabling back pain and were unable to participate in physical therapy activities after being admitted to an acute rehabilitation center. Both patients had bacterial discitis of the lumbar spine that was apparently caused by infected ischemic limb tissue, ultimately removed at below-knee amputation. The literature describes many cases of bacterial discitis infected from many sources, but not from ischemic limb tissue requiring subsequent amputation. Many such cases may exist, however, and earlier recognition of this condition will enable appropriate treatment before vertebral destruction and/or neurological sequelae.