The immediate effect of a novel audio-visual cueing strategy (simulated traffic lights) on dual-task walking in people with Parkinson's disease.

BACKGROUND: Gait deficits are exacerbated during the addition of a concurrent cognitive task in individuals with Parkinson's disease (PD). The provision of auditory and/or visual cues has been reported to facilitate gait performance in these patients. AIM: To investigate whether individuals with PD could use traffic lights as an audio-visual cueing strategy to enhance dual-task walking performance. DESIGN: Cross-sectional comparative study. SETTING: The Hong Kong Polytechnic University. POPULATION: Fifteen PD and 13 healthy individuals. METHODS: All participants were instructed to walk at their natural pace, followed by 2 randomized conditions: 1) walking while doing serial subtractions of three, starting from a random number between 60 to 100; 2) doing the same tasks with the addition of traffic lights signals as audio-visual cues. Primary outcomes included stride length, cadence and gait velocity. RESULTS: Individuals with PD had more deterioration in all gait parameters than healthy controls for both single- and dual-task walking. With the use of traffic lights, individuals with PD showed significant increases in stride length (by 8.8%), cadence (by 9.6%), and gait velocity (by 21.0%, P=0.000). CONCLUSION: Traffic lights could be used as combined preparatory and ongoing audio-visual cues to enhance dual-task walking performance in people with PD. CLINICAL REHABILITATION IMPACT: Positive findings from the present study suggest a promising treatment intervention to benefit people with PD, who often have to conduct concurrent cognitive task during walking in their daily activities.

Self-efficacy outcomes of people with brain injury in cognitive skill training using different types of trainer-trainee interaction.

PRIMARY OBJECTIVE: To evaluate the effects of different trainer-trainee interaction patterns on the self-efficacy outcomes of trainees with brain injury. RESEARCH DESIGN: A pre-test and post-test randomized clinical trial design. METHODS AND PROCEDURES: One hundred and three subjects with brain injury were recruited and 83 subjects participated in analogical problem-solving training that was delivered in three respective interaction modes: (a) direct trainer-trainee interaction, (b) self-paced computer-assisted and (c) on-line training with real-time audio-visual interaction. Quizzes on daily behavioural problem- solving and a problem-solving self-efficacy rating scale were adopted as outcome measures. The trainees in the trainer-administered group that received instructions in person with a continuous 'human touch' showed more significant improvement in their problem-solving self-efficacy than the two other groups. CONCLUSIONS: Interactive modes of cognitive skill training can be flexible enough to match the needs of individual trainees. However, human interaction is considered important in promoting self-efficacy in trainees with brain injury.

Mental imagery for relearning of people after brain injury.

OBJECTIVE: This paper reported on the application of mental imagery to the relearning of daily task performance in people with brain injury. METHOD: The changes in two subjects who had suffered from cerebral infarction shown throughout a 3-week mental imagery programme were described. The subjects' improvement in task performance and other clinical outcomes illustrated the programme's therapeutic effects on skill relearning, maintenance and generalization. RESULTS: After completing the programme, the subjects showed improvements in performance at both the trained and untrained tasks. Feedback from the patients also suggested its ability to enhance their day-to-day functioning. Clinical assessment results indicated that the subjects experienced an increase in the attention and sequential processing functions but not in the motor and other cognitive functions. CONCLUSION: Mental imagery appears to be effective at enhancing the task relearning of subjects after brain injury. The skills acquired under this treatment regime can be retained and then generalized to other tasks. Its therapeutic effect is probably mediated by the improved attention and planning and execution functions associated with the rehearsal. Further research should conduct clinical controlled trials to gather evidence on its efficacy at promoting functional regain in people suffering from neurological disorders.

Responses to whole head-and-body tilts with and without passive ankle dorsiflexion in the absence of visual feedback.

OBJECTIVES: We have investigated lower limb responses in seven blindfolded healthy subjects to well controlled tilts in the standing position. Our aims were (1) to determine the effect of head acceleration magnitude on responses evoked by whole head-and-body tilts, and (2) to establish whether tilt-evoked responses are modifiable by passive ankle dorsiflexion. Whole head-and-body tilts evoked responses in the biceps femoris, medial gastrocnemius and tibialis anterior muscles. METHODS: Seven young healthy subjects stood on a spring-activated tilting apparatus and underwent sudden whole head-and-body tilts of about 15 degrees from the vertical position, with or without passive ankle dorsiflexion. Head acceleration was recorded with a linear accelerometer and ankle angular displacement with a potentiometer. Surface EMG signals were recorded in the right biceps femoris, medial gastrocnemius and tibialis anterior muscles. RESULTS: As the peak of head acceleration was increased from 0.5 g to 1.8 g, the frequency of occurrence of tilt-evoked responses increased from 7% to 60% of trials in the biceps femoris muscle during whole head-and-body tilts. In general, the more proximal muscle (biceps femoris) was activated before the more distal muscle (medial gastrocnemius) during whole head-and-body tilts, while the opposite pattern was found during tilt with dorsiflexion. CONCLUSIONS: Our results indicate that the occurrence of tilt-evoked responses increases with an increase in the amplitude of tilting acceleration. This suggests that tilt-evoked responses are dependent, at least in part, on vestibular stimulation. In addition, the spatio-temporal pattern of biceps femoris and medial gastrocnemius muscle activation was opposite during whole head-and-body tilts and tilts with dorsiflexion. This finding suggests that foot/ankle somatosensory inputs can modify tilt-evoked responses.

Community-based cognitive rehabilitation services for persons with traumatic brain injuries in China.

The present study aims to explore the need for cognitive rehabilitation services (CRS) in the community for persons with brain injuries and to understand the level of knowledge and attitudes towards cognitive rehabilitation of health care professionals in the city of Guangzhou in southern China, including their use of innovative CRS. One hundred and fifty-five medical and allied health professionals responded to a self-administered questionnaire. Of this number, 128 completed questionnaires were returned; a response rate of 82.58%. Of the respondents, 95.4% agreed with the need to develop CRS in China. They identified four areas as those for which CRS is most urgently needed: language, memory, orientation and attention rehabilitation. The relative appropriateness of settings for such CRS delivery was ranked, from most to least, as the home, hospital and community, respectively. In prioritising the modes of CRS, it was suggested that the order of preference would be face-to-face, computer-assisted and online/web-based. Home-based intervention was also ranked top among the service treatment settings. The respondents also showed a preference for the innovative online mode, which they felt should be conducted in a home rather than a hospital setting.

Learning to live independently with expert systems in memory rehabilitation.

Expert systems (ES), which are a branch of artificial intelligence, has been widely used in different applications, including medical consultation and more recently in rehabilitation for assessment and intervention. The development and validation of an expert system for memory rehabilitation (ES-MR) is reported here. Through a web-based platform, ES-MR can provide experts with better decision making in providing intervention for persons with brain injuries, stroke, and dementia. The application and possible commercial production of a simultaneously developed version for "non-expert" users is proposed. This is especially useful for providing remote assistance to persons with permanent memory impairment when they reach a plateau of cognitive training and demand a prosthetic system to enhance memory for day-to-day independence. The potential use of ES-MR as a cognitive aid in conjunction with WAP mobile phones, Bluetooth technology, and Personal Digital Assistants (PDAs) is suggested as an avenue for future study.

Self-regulatory learning and generalization for people with brain injury.

PRIMARY OBJECTIVE: brain injury can result in the loss of previous learnt behaviours that affect an individual's daily functioning. The use of self-regulation helps the individual to relearn the lost behaviours by bringing him/her to self-conscious level through independent and reflective learning derived using a social cognitive perspective. The purpose of this paper is to report on clinical observations made with the use of self-regulation in people with brain injury during the relearning of lost functions. METHODS AND PROCEDURES: daily tasks were used to assess the relearning ability of the subjects pre- and post-programme. EXPERIMENTAL INTERVENTION: one-week self-regulatory training on five selected daily tasks. MAIN OUTCOMES AND RESULTS: these provisory observations would suggest that, with specific guidance for people with different needs, such as with impaired cognitive function and depression, self-regulation is effective in enhancing their relearning. CONCLUSION: Self-regulatory training is effective in enhancing the relearning of lost functions.

Mental set can modulate response onset in the lower limb muscles to falls in humans.

The objective of this study was to investigate the modulation of the ankle muscle electromyographic (EMG) response as a function of mental set. Thirteen young healthy subjects underwent 40 unexpected and self-initiated drops from 30 cm above two separate force-plates. Following unexpected drops, reflex activities were observed in the medial gastrocnemius (MG) and tibialis anterior (TA) at mean latencies (+/- SD) of 83.59 +/- 10.1 and 99.43 +/- 21.82 ms, respectively. Following self-initiated drops, the response latency of the MG was significantly shortened (to 71.98 +/- 10 ms, P<0.05), and the TA was significantly lengthened (to 183.33 +/- 45 ms, P<0.05) when compared with unexpected drops. Such a modulation was associated with a significant reduction of the impact force on landing as compared with unexpected drops (by 17%, P<0.05). Interestingly, a negative correlation was found between the onset of the TA EMG response and the magnitude of the impact force on landing during expected (r= -0.66, P<0.05) but not unexpected drops.

Evaluation of physiological work demands and low back neuromuscular fatigue on nurses working in geriatric wards.

This study evaluated the physiological demands and low back neuromuscular fatigue patterns following a daytime work shift of 21 female nurses working in geriatric wards. Subjects' heart rate (HR) at work was monitored for 8 h and surface electromyogram (EMG) of their back muscle was recorded during a 1-minute horizontal trunk holding test before and after work. Results showed that the nurses had heart rates exceeding 90 beats/min in 57% and 110 beats/min in 19% of their working hours. The EMG revealed a significant drop in initial median frequency (MF) (p = 0.04) and increase in negative slope of the MF/time plot (p<0.001) of the back muscle after work. These suggest that the muscles were fatigued after work. The nurses rated patient lifting, transfer and turning as most physically demanding, and these corresponded to the highest heart rates recorded. The physiological and neuromuscular strain on the nurses indicated that extreme care should be exercised at work, particularly towards the end of a work shift when the muscles have become fatigued.

The motor dysfunction of patients with knee osteoarthritis in a Chinese population.

OBJECTIVE: To determine the extent of motor dysfunction in people with knee osteoarthritis (OA), as compared with similarly aged subjects without knee OA, in a Chinese population. METHODS: Seventy-six subjects participated in this study. Isometric peak torque of the knee muscles, range of knee motion at rest and during walking, gait velocity, cadence, and stride length were compared. RESULTS: The isometric peak torque of both the quadriceps and the hamstrings of the affected leg of patients with knee OA were weaker than those of the controls (most P < 0.05). The gait velocity was 23.4% slower (P = 0.001), the cadence 33.3% less (P < 0.001), and the stride length 13.4% shorter (P = 0.010) in the patients with OA. The range of knee motion in the patients was reduced by 11.2% at rest (P = 0.003) and by 14.7% during walking (P = 0.001). CONCLUSION: Patients with knee OA exhibited statistically significant deficiencies in the physical performance tested, as compared with similarly aged subjects without knee OA (by 9.6% to 33.3%), in a Chinese population. The indication that this study group seems less severely limited than those reported in Western literature warrants further investigation.

Consistency of performance on the functional capacity assessment: static strength and dynamic endurance.

OBJECTIVE: To explore the degree of consistency in a subject's performance in physical strength and endurance. DESIGN: Thirty healthy men, aged 19 to 26 yr, were recruited to participate in protocols to assess static strength and dynamic endurance tests on their upper limbs with the Baltimore Therapeutic Equipment Primus. Retests were conducted 7 days after the initial test. RESULTS: The intraclass correlation coefficients were 0.71 to 0.97 and 0.32 to 0.90 for static and dynamic endurance strengths, respectively. These results indicated that the consistency of the subjects' performance across occasions was high for testing static strength, although it was more varied for testing endurance strength. CONCLUSIONS: Higher consistency was observed among subjects in the assessment of static strength than dynamic endurance strength. The range of motion traveled by the limb, speed of performance, and ergonomic design of attachments seemed to confound the subjects' performance on the instrument. Stringent assessment protocols, ergonomically designed hardware, and clear instructions and practice trials before the formal testing were essential to maximize the subjects' consistency of performance. The results of this study were applicable and generalized to other performance-based instruments for physical and functional capacity evaluation and work simulators.

Work profile and functional capacity of formwork carpenters at construction sites.

PURPOSE: This study established a work profile and functional capacity for formwork carpenters (FCs) working at construction sites. METHOD: Thirty male FCs aged 19-45 were recruited by convenient sampling from the construction training centres. All FCs participated in an interview/questionnaire and a standardized functional capacity evaluation (FCE) using the Baltimore Therapeutic Equipment Primus (BTE Primus) and Valpar Component Work Sample (VALPAR19). Thirty male adults (office workers) aged 19-45 participated in the exact FCE for comparison. RESULTS: The results of the questionnaire indicated that the job demands of formwork carpenters were frequent lifting (46.7%), carrying (50.0%) and handling (60.0%). Significantly higher lifting and carrying capacities were revealed among the FCs, but not in their isometric strengths and the endurance of the upper limbs (chi2 = 6.48, df = 2, p < 0.05). CONCLUSIONS: The dynamic and repetitive sub-maximal nature of the work of formwork carpentry induced an elevation of job-specific lifting and carrying capacities among the FCs. The job and functional capacity profiles would be useful for formulating guidelines for the rehabilitation of injured workers and the training of new workers in the trade.

Reflex interactions during whole head-and-body tilts are modified by age in humans.

We have demonstrated that lower limb extensor muscle response to tibial nerve stimulation is significantly facilitated by whole head-and-body tilt in the forward direction. Our aim was to examine whether this reflex interaction is influenced by age. Reflexes were elicited in lower limb muscles by electrical stimulation (ES) of the right tibial nerve. We compared reflexes during supported stance (ESalone) and sudden forward tilting of the whole head-and-body (Tilt+ES) between 10 healthy subjects aged 66 +/- 4 years and 13 subjects aged 27 +/- 3 years. In young subjects the area of response evoked in the ipsilateral vastus lateralis (iVL) was significantly increased by 74% during Tilt+ES as compared with ESalone (p < 0.05). Moreover, the latency of contralateral VL and soleus muscle responses (cVL and/or cSO) was significantly shorter by 61 ms during Tilt+ES than ESalone (p < 0.01). In contrast, older subjects showed no significant increase in the excitability of iVL muscle response and cVL and/or cSO muscle responses during Tilt+ES as compared with ESalone, despite the application of similar intensity of ES and head acceleration as in young subjects. Our findings showed that the interaction between ES-evoked and tilt-evoked responses in lower limb extensor muscles is modified with age, which suggests modifications of sensorimotor integration involved in balance control.

Human soleus H-reflex excitability is decreased by dynamic head-and-body tilts.

The modulation of soleus (SO) H-reflex excitability during dynamic whole head-and-body tilts (WHBT) was investigated in normal healthy subjects. Between 30 and 70 ms, and 151 and 190 ms after head acceleration onset, the H-reflex amplitude was smaller than during quiet standing by 7.6% (p < 0.01) and 15.4% (p = 0.06) respectively. This finding suggested that dynamic WHBT reduced the excitability of the predominantly monosynaptic stretch reflex are in the majority of the subjects studied.

Transcutaneous electrical nerve stimulation: nonparallel antinociceptive effects on chronic clinical pain and acute experimental pain.

OBJECTIVE: To investigate to what extent a single 60-minute session of transcutaneous electrical nerve stimulation (TENS) would modify chronic clinical pain, acute experimental pain, and the flexion reflex evoked in chronic low back pain patients. STUDY DESIGN: Thirty young subjects with chronic low back pain were randomly allocated to two groups, receiving either TENS or placebo stimulation to the lumbosacral region for 60 minutes. The flexion reflex was elicited by an electrical stimulation applied to the subject's right sole and recorded electromyographically from the biceps femoris and the tibialis anterior muscles. MAIN OUTCOME MEASURES: Subjective sensation of low back pain and the electrically induced pain were measured by two separate visual analog scales, termed VAS(LBP) and VAS(FR), respectively. Data obtained before, during, and 60 minutes after TENS and placebo stimulations were analyzed using repeated measures ANOVA. RESULTS: The VAS(LBP) score was significantly reduced to 63.1% of the prestimulation value after TENS (p<.001), but the reduction was negligible after placebo stimulation (to 96.7%, p = .786). In contrast, no significant change was found in the VASFR score (p = .666) and the flexion reflex area (p = .062) during and after stimulation within each group and between the two groups (p = .133 for VASFR and p = .215 for flexion reflex area). CONCLUSIONS: The same TENS protocol had different degrees of antinociceptive influence on chronic and acute pain in chronic low back pain patients.

Intense peripheral electrical stimulation evokes brief and persistent inhibition of the nociceptive tail withdrawal reflex in the rat.

In a study of modulation of nociception by sensory inputs, electrical stimulation was applied to specific sites in the hindlimb and effects on the nociceptive tail withdrawal reflex were monitored in the lightly anaesthetized rat. Stimulation was applied to previously defined sites in the hindlimb, meridian points femur-futu (ST-32), fengshi (GB-31) and zusanli (ST-36). It consisted of a 4 Hz train of 2 ms square pulses given for 20 min at 20 x the threshold intensity required for muscle twitch. Tail withdrawal was provoked by application of a noxious heat stimulus applied to the tip of the tail. Results were expressed as a percentage of the maximal possible inhibition which is achieved when the post-treatment latency is 2 x the pre-treatment latency otherwise known as the cut off. During stimulation, the latency of the withdrawal increased to approximately 70% of the maximal possible inhibition. Following stimulation, the inhibition persisted for > 1 h. Stimulation at 2 or 6 Hz elicited similar effects but stimulation at 8 Hz evoked inhibition during the stimulation only. Stimulation applied to sites away from defined meridian points inhibited tail withdrawal during the stimulation; no post-stimulation effect was produced. In acutely transected animals (< or = 48 h), stimulation of meridian points elicited a small, brief increase in latency but during stimulation only. At 7 and 14 days after spinal transection, this response during stimulation was greater in magnitude and a brief post-stimulation increase was also observed. The return of this latter effect was coincident with the return of bladder function. These data suggest that high intensity, low frequency electrical stimulation of hindlimb meridian points in the lightly anaesthetized rat produces both brief and persistent inhibitory effects on the nociceptive tail withdrawal reflex. These effects appear to be elicited by different mechanisms. The persistent effect may represent a plastic change in central inhibitory mechanisms. Data from spinal animals indicate a major participation of supraspinal structures but that spinal mechanisms are also capable of sustaining both types of effect.

Responses to dynamic head-and-body tilts are enhanced in Parkinson's disease.

BACKGROUND: Previous studies demonstrated that destabilizing responses to slow perturbations were enhanced in patients with Parkinson's disease (PD). Our objectives were to investigate the influence of PD on responses to faster whole head-and-body tilts in the standing position, and to establish whether any modification of tilt-evoked responses in PD patients was related to possible changes in the modulation of soleus (SO) H-reflex. METHODS: Ten PD patients and 10 age-matched normal subjects assumed a standing position on an L-shaped tilting apparatus. Their head and shoulders were firmly attached to the back support of the apparatus, while their feet were fixated to the standing platform. With their vision occluded, the subjects's whole head-and-body was suddenly tilted forward to 20 degrees, at a peak head acceleration of 0.7 g +/- 0.1 g. Tilt-evoked responses were recorded from the lower limb muscles bilaterally. In addition, 40 H-reflexes were elicited in the SO muscle at 30-190 ms intervals after the onset of head acceleration. The M response amplitude was kept within +/- 15% of its control value. RESULTS: PD patients demonstrated an abnormally high responsiveness to whole head-and-body tilts in comparison with age-matched normal subjects. This was shown by the significantly larger proportion of PD patients manifesting responses in the SO, biceps femoris and vastus lateralis muscles (p < 0.05), as well as their significantly larger SO response area (413%; p < 0.01). In contrast, the amplitude of the SO H-reflex was significantly increased by only 14% (p < 0.05) in these patients, and only at 30-70 ms after head acceleration onset. CONCLUSIONS: The overexcitable tilt-evoked responses of PD patients could originate from a reduced ability to suppress responses when the body is supported. This enhanced excitability of tilt-evoked responses was probably not due to motoneuronal hyperexcitability or decreased presynaptic inhibition of the group Ia terminals involved in the mainly monosynaptic H-reflex pathway. Thus, we hypothesize that the control of spinal interneurons involved in the tilt-evoked responses may be defective in PD.

Extensor muscle responses to tibial nerve stimulation are enhanced during dynamic tilts in standing humans.

We studied the interaction between muscle responses evoked in standing by electrical stimulation (ES) of the tibial nerve and dynamic tilts of the head-and-body in 13 young healthy subjects. Subjects were attached to an L-shaped tilting apparatus and underwent sudden forward tilting of their head-and-body as a whole, without ankle rotation. During such tilts, the area of response evoked in the ipsilateral vastus lateralis (iVL) muscle by the ES was significantly increased by 74% as compared to quiet supported stance (P = 0.01). The response latency of the contralateral VL and soleus muscles i.e. the crossed extension reflex, was significantly shorter during tilt (54 +/- 22 ms) than during quiet supported stance (115 +/- 13 ms, P < 0.01). The increased excitability of extensor muscles activated by ES during tilt seems appropriate to maintain stance during a forward perturbation of the body.

SR 48968 specifically depresses neurokinin A- vs. substance P-induced hyperalgesia in a nociceptive withdrawal reflex.

To determine the role of neurokinin A and tachykinin NK2 receptors in processing of nociceptive information at the spinal level, the selective NK2 receptor antagonist, SR 48968 (S)-N-methyl-N [4-(4-acetylamino-4-[phenyl piperidino)-2-(3,4-dichlorophenyl)-butyl] benzamide, was tested for its effects on the hyperalgesia produced in the tail flick reflex by intrathecal administration of neurokinin A and of substance P. SR 48968 was also tested in a model in which noxious peripheral stimulation has been shown to produce hyperalgesia via a substance P mechanism. SR 48968 given intrathecally had a dose-dependent inhibitory effect on both the behaviour and the hyperalgesia induced by neurokinin A but not on either of these effects produced by substance P. In addition, systemic administration of SR 48968 depressed the hyperalgesic effect of intrathecal administration of neurokinin A. First, this evidence indicates a unique role for neurokinin A in the spinal cord as distinct from that of its homologue, substance P. and confirms that neurokinin A acts via the tachykinin NK2 receptor, rather than non-specifically via the NK1 receptor. Second, the data indicate that in this model substance P does not express any of its effects non-selectively via activation of NK2 receptors. Third, SR 48968 appears to have access to the spinal cord upon systemic administration. Fourth, intrathecal administration of the NK1 receptor antagonist, CP-96,345 [(2S,3S)-cis-2-(diphenylmethyl)-N-[(2-methoxy-phenyl)-methyl]-1- azabicyclo [2.2.2]-octan-3-amine], had no effect on the responses to intrathecal administration of neurokinin A. Finally, the hyperalgesia produced by sustained noxious thermal stimulation of the tip of the tail was unaffected by intrathecal administration of SR 48968; thus, it remains to find a physiological response in which endogenous neurokinin A and NK2 receptors at the spinal level are involved in the rat in vivo.

Functional modulation of the human flexion and crossed extension reflexes by body position.

The effects of body position on the electrically evoked flexion (FR) and crossed extension reflexes (CER) were investigated in humans. The FR area in the ipsilateral tibialis anterior muscle was significantly smaller during sitting than supported stance by 36% (P < 0.01). In contrast, the excitability of extensor muscles on both sides was enhanced in standing. For instance, twice as many subjects manifested a response in the ipsilateral vastus lateralis (VL) and the contralateral VL and/or soleus muscles (i.e. the CER) in standing than sitting. The FR and CER modulation observed seems to be dictated by the difference in functional demand between sitting and supported stance.