Kingston Centre

Results of our previous studies have shown that the slow, shuffling gait of Parkinson's disease patients is due to an inability to generate appropriate stride length and that cadence control is intact and is used as a compensatory mechanism. The reason for the reduced stride length is unclear, although deficient internal cue production or inadequate contribution to cortical motor set by the basal ganglia are two possible explanations. In this study we have examined the latter possibility by comparing the long-lasting effects of visual cues in improving stride length with that of attentional strategies. Computerized stride analysis was used to measure the spatial (distance) and temporal (timing) parameters of the walking pattern in a total of 54 subjects in three separate studies. In each study Parkinson's disease subjects were trained for 20 min by repeated 10 m walks set at control stride length (determined from control subjects matched for age, sex and height), using either visual floor markers or a mental picture of the appropriate stride size. Following training, the gait patterns were monitored (i) every 15 min for 2 h; (ii) whilst interspersing secondary tasks of increasing levels of complexity; (iii) covertly, when subjects were unaware that measurement was taking place. The results demonstrated that training with both visual cues and attentional strategies could maintain normal gait for the maximum recording time of 2 h. Secondary tasks reduced stride length towards baseline values as did covert monitoring. The findings confirm that the ability to generate a normal stepping pattern is not lost in Parkinson's disease and that gait hypokinesia reflects a difficulty in activating the motor control system. Normal stride length can be elicited in Parkinson's disease using attentional strategies and visual cues. Both strategies appear to share the same mechanism of focusing attention on the stride length. The effect of attention appears to require constant vigilance to prevent reverting to more automatic control mechanisms.

To identify the fundamental deficit in gait hypokinesia in Parkinson's disease (PD) we conducted a series of experiments that compared PD subjects with age- and height-matched controls in their capacity to regulate either stride length, cadence (steps per minute) or both parameters to three conditions. In the first condition the spatial and temporal parameters of gait were documented for slow, normal and fast walking. The second condition compared parkinsonian gait with the walking pattern of elderly controls whilst controlling for two movement speeds: fast (control preferred) speed and slow (PD preferred) speed. In the third condition we examined the ability of PD subjects to regulate one parameter (e.g. stride length) when the other two parameters (e.g. velocity and cadence) were held at control values. A total of 34 PD subjects and 34 matched controls were tested using a footswitch stride analysis system that measured the spatial and temporal parameters of gait for a series of 10 m walking trials. Parkinsonian subjects exhibited marked gait hypokinesia in each of the experiments. Although they retained the capacity to vary their gait velocity in a similar manner to controls, their range of response was reduced. Within the lower velocity range, PD subjects could vary their speed of walking by adjusting cadence and, to a lesser extent, stride length. However, when the speed of walking was controlled, the stride length was found to be shorter and the cadence higher in PD subjects than in controls. Stride length could not be upgraded by internal control mechanisms in response to a fixed cadence set for age and height-matched velocity. In contrast, cadence was readily modulated by external cues and by internal control mechanisms when stride length was fixed to the values obtained for age- and height-matched controls. It was concluded that regulation of stride length is the fundamental problem in gait hypokinesia and the relative increase in cadence exhibited by PD subjects is a compensatory mechanism for the difficulty in regulating stride length. These findings are discussed in the context of the hypothesized role of the basal ganglia in generating internal cues for the maintenance of the gait sequence and in relation to the structuring of movement rehabilitation strategies.

This study classified speech impairment in 200 patients with Parkinson's disease (PD) into five levels of overall severity and described the corresponding type (voice, articulation, fluency) and extent (rated on a five-point scale) of impairment for each level. From two-minute conversational speech samples, parameters of voice, fluency and articulation were assessed by two trained-raters. Voice was found to be the leading deficit, most frequently affected and impaired to a greater extent than other features in the initial stages. Articulatory and fluency deficits manifested later, articulatory impairment matching voice impairment in frequency and extent at the 'Severe' stage. At the final stage of 'Profound' impairment, articulation was the most frequently impaired feature at the lowest level of performance. This study illustrates the prominence of voice and articulatory speech motor control deficits, and draws parallels with deficits of motor set and motor set instability in skeletal controls of gait and handwriting.

BACKGROUND AND PURPOSE: The Timed "Up & Go" Test (TUG) is used to measure the ability of patients to perform sequential locomotor tasks that incorporate walking and turning. This study investigated the retest reliability, interrater reliability, and sensitivity of scores obtained with the TUG in detecting changes in mobility in subjects with idiopathic Parkinson disease (PD). SUBJECTS: The performance of 12 people with PD was compared with that of 12 age-matched comparison subjects without PD. METHODS: The subjects with PD completed 5 trials of the TUG after withdrawal of levodopa for 12 hours ("off" phase of the medication cycle) as well as an additional 5 trials 1 hour after levodopa was administered ("on" phase of the medication cycle). They were scored on the Modified Webster Scale at both sessions. The comparison subjects also performed 5 TUG trials. All trials were videotaped and timed by 2 experienced raters. The videotape was later rated by 3 experienced clinicians and 3 inexperienced clinicians. RESULTS: For the subjects with PD, within-session performance was highly consistent, with correlations (r) ranging from.80 to.98 for the "off" phase and from.73 to.99 for the "on" phase. The performance of the comparison subjects across the 5 trials was also highly consistent (r=.90-.97). Comparisons showed differences between trials 1 and 2 on the TUG for both groups. Removal of data for trial 1 (the practice trial) further enhanced retest reliability. There was close agreement in TUG scores among raters despite different levels of experience (intraclass correlation coefficient [3,1]=.87-.99). Mean TUG scores were different between the "on" and "off" phases of the levodopa cycle and between subjects with PD and comparison subjects during the "on" phase. CONCLUSION AND DISCUSSION: Retest reliability and interrater reliability of the TUG measurements were high, and the measurements reflected changes in performance according to levodopa use. The TUG can also be used to detect differences in performance between people with PD and elderly people without PD.

BACKGROUND AND PURPOSE: Exacerbation of movement disorders while doing 2 tasks (dual task performance) is a characteristic feature of Parkinson disease (PD). The aim of this investigation was to identify whether the type of secondary task (motor or cognitive) determined the severity of dual task interference. SUBJECTS AND METHODS: Footstep patterns for 15 people with PD and 15 comparison subjects without PD were compared when they walked: (1) at a self-selected speed, (2) while simultaneously performing a motor task (coin transference), and (3) while simultaneously performing a cognitive task (digit subtraction). Gait speed, stride length, cadence, and the percentage of the gait cycle in double-limb stance (DS) were examined with a computerized stride analyzer. RESULTS: When there was no second task, the mean stride length was less in the group with PD (1.29 m) than in the comparison group (1.51 m), and the mean gait speed was less in the group with PD (71.47 m/min) than in the comparison group (87.29 m/min). The mean cadence was less in the group with PD (110.79 steps/min) than in the comparison group (115.81 steps/min). The percentage of the gait cycle in DS was greater in the group with PD (33.38%) than in the comparison group (31.21%). Both groups reduced their stride length and speed when they had to change from unitask performance to dual task performance and DS increased. For the group with PD, cadence also decreased. For both groups, the type of secondary task had a negligible effect on the performance decrement. DISCUSSION AND CONCLUSION: Although the performance of simultaneous motor or cognitive tasks compromised gait in people with PD, the type of secondary task was not a major determinant of the severity of dual task interference.

Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) which are associated with the preparation and execution of voluntary, or internally determined movements. Supplementary motor area activity may be abnormal in Parkinson's disease since its major input from the basal ganglia is disrupted. Investigation of the abnormalities in supplementary motor area activity associated with movement deficits in Parkinson's disease may therefore reveal functions of the basal ganglia and the supplementary motor area. Movement-related potentials associated with sequential movements were investigated under various cueing conditions in Parkinson's disease subjects and age-matched controls. In controls, MRPs revealed involvement of the supplementary motor area in movements which can be internally determined (non-cued and externally cued, predictable movements, but not unpredictable movements). In Parkinson's disease, however, the supplementary motor area was only involved in movements which must be internally determined (non-cued movements, but not externally cued movements); therefore impaired internal control mechanisms, operating via the supplementary motor area, are bypassed when external cues are given. As a result, Parkinson's disease patients are more reliant on external cues and are unable to use predictive models to internally guide movement. Supplementary motor area involvement also relied on the predictability (in controls) or presence (in Parkinson's disease) of timing cues and not spatial cues, indicating a role of the supplementary motor area and basal ganglia in the temporal organizations of sequential movement rather than the programming of specific movements. For non-cued movements, abnormalities in MRPs for Parkinson's disease subjects consisted of delayed MRP onset and peak times, and prolonged cortical activity following movement. These observations led to a proposed model of the interaction between the basal ganglia and the supplementary motor area, involving the temporal organization of voluntary and internally determined sequential movements.

Freezing of gait (FOG) has been identified as one of the main contributors to gait disturbances in Parkinson's disease. While the pathophysiology remains enigmatic, several factors such as step length and the sequence effect (step to step reduction in amplitude) may lead to the occurrence of FOG. It was hypothesized that by reducing step length, FOG episodes would present more frequently if a significant sequence effect (measured as a regression slope) was co-existent in the subject. Twenty-six participants with Parkinson's disease were separated clinically into a freezing (PD + FOG, n = 16) and non-freezing (PD-FOG, n = 10) group, with 10 age-matched control participants. Testing involved walking trials where preferred step length was set at 100%, 75%, 50% and 25% of normalized step length. The number of FOG episodes increased in the 50% condition and further increased in the 25% condition compared to other conditions. The participants with FOG also demonstrated a larger average regression slope, with significant differences in the 75%, 50% and 25% conditions when compared to the PD-FOG and control groups. There were no significant differences when comparing the slope of the PD-FOG and control group, indicating the reduced step length and the sequence effect may have led to the occurrence of FOG. These findings support the possible dual requirement of a reduced step length and a successive step to step amplitude reduction to lead to FOG.

We examined whether people with Parkinson's disease (PD) have a central amplitude regulation disorder using three-dimensional (3-D) gait analyses to compare the effects of medication and attentional strategies on gait in 12 PD subjects and 12 matched comparison subjects. Subjects with PD first performed several 10-m gait trials at preferred speed while off levodopa. They then walked at preferred speed on levodopa; off levodopa with cues; and on levodopa with cues. Control subjects walked at preferred speed and then with visual cues to match their stride length to PD values. As well as spatiotemporal footstep data, pelvic and lower limb kinematic profiles and angle-angle diagrams were produced for sagittal, coronal, and transverse plane movements using a 3-D motion analysis system. In people with PD, decreased step length was accompanied by reduced movement amplitude across all lower limb joints, in all movement planes. When control subjects were required to walk with short steps matched to the size of PD comparisons, they displayed a similar multijoint reduction in amplitude. For PD subjects, both levodopa and visual cues increased movement amplitude across all lower limb joints. Amplitude increased further when levodopa and visual cues were combined, resulting in normalization of step length. This finding suggested that reduced step length is due to a mismatch between cortically selected movement amplitude and basal ganglia maintenance mechanisms. Levodopa and cues normalized amplitude across all joints by altering motor set and bypassing defective basal ganglia mechanisms.

The purpose of this investigation was to clarify abnormalities in the stride length-cadence relation in gait hypokinesia in Parkinson's disease (PD). A second aim was to investigate the effect of levodopa medication on the foot-step pattern. In the first experiment, 20 subjects with idiopathic PD and 20 age-, sex-, and height-matched controls performed a series of 10 m walking trials at cadence rates ranging from 40 steps/min to 180 steps/min. Cadence rates were set by an electronic metronome, and gait patterns were measured by using a footswitch stride-analyzer system. By instructing subjects to concentrate on walking in time to the metronome beat, the baseline stride length could be monitored for a range of velocities with the compensatory effects of cadence removed. Linear-regression analysis revealed that the mean slope for the regression of stride length against cadence was not different from normal in PD, although there was a statistically significant difference in mean intercept between the PD group (0.25) and the control group (0.59); [t (19) = -4.76; p = 0.0001]. The second experiment evaluated the effects of levodopa on stride-length regulation in 10 subjects with idiopathic PD on average 45 min before and after the first morning dose was administered. There was a statistically significant increase in stride length for all cadence rates from premedication to postmedication phases and the maximal stride length was achieved at higher cadence rates after medication. The slope of the regression of stride length against cadence did not alter according to medication status, although the mean intercept was significantly lower before levodopa (-0.06) compared with after levodopa (0.27); [t (9) = -3.83; p = 0.004]. These results suggest that defective scaling of stride length underlies gait disturbance in PD.

Festination and freezing of gait (FOG) are poorly understood gait disorders that cause disability and falls in people with Parkinson disease (PD). In PD, basal ganglia malfunction leads to motor set deficits (hypokinesia), while altered motor cue production leads to a sequence effect, whereby movements becomes progressively smaller as in festination. We suggest both factors may contribute to FOG. Disturbance of set maintenance by the basal ganglia in PD has previously been examined in gait, but limited systematic evaluation of the sequence effect exists. In this study, we investigated the step-to-step amplitude relationship in 10 PD subjects with clinical evidence of festination and FOG. Four conditions were examined: off levodopa, off with attentional strategies, off with visual cues, and on levodopa. Participants demonstrated a sequence effect (F = 6.24; P = 0.001), which was reversed only by use of visual cues. In contrast, medication, attentional strategies, and visual cues all improved hypokinesia. Variability was marked both within and between participants in all conditions. The variability of FOG is suggested to relate to a combination of factors, including the sequence effect and its variability, as well as the severity of hypokinesia and its response to medications.

This randomized controlled clinical trial was conducted to compare the effects of movement rehabilitation strategies and exercise therapy in hospitalized patients with idiopathic Parkinson's disease. Participants were randomly assigned to a group that received movement strategy training or musculoskeletal exercises during 2 consecutive weeks of hospitalization. The primary outcome was disability as measured by the Unified Parkinson's Disease Rating Scale, UPDRS (motor and ADL components). Secondary outcomes were balance, walking speed, endurance, and quality of life. Assessments were carried out by blinded testers at baseline, after the 2 weeks of treatment and 3 months after discharge. The movement strategy group showed improvements on several outcome measures from admission to discharge, including the UPDRS, 10 m walk, 2 minute walk, balance, and PDQ39. However, from discharge to follow up there was significant regression in performance on the 2 minute walk and PDQ39. For the exercise group, quality of life improved significantly during inpatient hospitalization and this was retained at follow-up. Inpatient rehabilitation produces short term reductions in disability and improvements in quality of life in people with Parkinson's disease.

OBJECTIVE: This paper provides a systematic review of research findings published between 1989 and 1998 concerning non-pharmacological strategies to alleviate behavioural disturbances in elderly persons with dementia. METHOD: Data collection strategies included computer literature searches, manual searches of selected journals and checks of references listed in previous reviews. To warrant inclusion, studies were required to include some measure of behaviour before and after the introduction of an intervention. Papers were appraised in the following domains: design, sampling technique, setting, behaviours studied, measurement tools, data collection methods, type of interventions and feasibility. An overall validity rating was assigned to each article using predetermined rules. RESULTS: Forty-three studies met criteria for inclusion including five randomised controlled trials. Validity ratings were as follows: one strong, 15 moderate, and 27 weak. Areas of scientific weakness included small numbers of subjects, inadequate descriptions of study participants, imprecise data collection methods, high attrition rates and insufficient statistical analysis. Despite this, there is evidence to support the efficacy of activity programs, music, behaviour therapy, light therapy, carer education and changes to the physical environment. The evidence in favour of multidisciplinary teams, massage and aromatherapy is inconclusive. CONCLUSIONS: It was easier to interpret the results of rigorously designed studies that focused on a single behaviour or single intervention tailored to the needs of individuals and carers. Future studies should seek to replicate the findings outlined here, improving methodologies where necessary and including outcome measures that encompass the interests of people with dementia, family caregivers and health professionals.

OBJECTIVE: To evaluate the effect of the 6-PACK programme on falls and fall injuries in acute wards. DESIGN: Cluster randomised controlled trial. SETTING: Six Australian hospitals. PARTICIPANTS: All patients admitted to 24 acute wards during the trial period. INTERVENTIONS: Participating wards were randomly assigned to receive either the nurse led 6-PACK programme or usual care over 12 months. The 6-PACK programme included a fall risk tool and individualised use of one or more of six interventions: "falls alert" sign, supervision of patients in the bathroom, ensuring patients' walking aids are within reach, a toileting regimen, use of a low-low bed, and use of a bed/chair alarm. MAIN OUTCOME MEASURES: The co-primary outcomes were falls and fall injuries per 1000 occupied bed days. RESULTS: During the trial, 46 245 admissions to 16 medical and eight surgical wards occurred. As many people were admitted more than once, this represented 31 411 individual patients. Patients' characteristics and length of stay were similar for intervention and control wards. Use of 6-PACK programme components was higher on intervention wards than on control wards (incidence rate ratio 3.05, 95% confidence interval 2.14 to 4.34; P<0.001). In all, 1831 falls and 613 fall injuries occurred, and the rates of falls (incidence rate ratio 1.04, 0.78 to 1.37; P=0.796) and fall injuries (0.96, 0.72 to 1.27; P=0.766) were similar in intervention and control wards. CONCLUSIONS: Positive changes in falls prevention practice occurred following the introduction of the 6-PACK programme. However, no difference was seen in falls or fall injuries between groups. High quality evidence showing the effectiveness of falls prevention interventions in acute wards remains absent. Novel solutions to the problem of in-hospital falls are urgently needed. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12611000332921.

This study contrasted the volume level of speech production with perceived volume. Fifteen idiopathic patients with Parkinson's disease who have hypophonic dysarthria and 15 healthy age- and sex-matched control subjects participated in this study. Testing took place in a sound-proof room. Ability to regulate volume was tested at three instructional levels of loudness: participants were given no instructions regarding volume (to elicit normal default volume) or were asked to read loudly or quietly. Two types of volume-perception judgments were made. First, an estimate of one's own volume, immediately after speaking (that is, immediate perception), and secondly, an estimation of reading volume after hearing one's own voice played back (that is, playback perception). These perceptual ratings were compared with actual speech volume produced in reading and conversation tasks. It was found that there was less of a difference between patients' production and perception of speech volume compared with that of the control subjects. While patients spoke more quietly than control subjects, they nevertheless perceived (immediate and playback perception) their own speech to be louder than did the control subjects. Patients overestimated the volume of their speech during both reading and conversation. The findings raise the question as to whether impaired speech production is driven by a basic perceptual fault or whether perception is abnormal as a consequence of impaired mechanisms involved in the generation of quiet speech.

While the beneficial effect of levodopa on traditional motor control tasks have been well documented over the decades, its effect on speech motor control has rarely been objectively examined and the existing literature remains inconclusive. This paper aims to examine the effect of levodopa on speech in patients with Parkinson's disease. It was hypothesized that levodopa would improve preparatory motor set related activity and alleviate hypophonia. Patients fasted and abstained from levodopa overnight. Motor examination and speech testing was performed the following day, pre-levodopa during their "off" state, then at hourly intervals post-medication to obtain the best "on" state. All speech stimuli showed a consistent tendency for increased loudness and faster rate during the "on" state, but this was accompanied by a greater extent of intensity decay. Pitch and articulation remained unchanged. Levodopa effectively upscaled the overall gain setting of vocal amplitude and tempo, similar to its well-known effect on limb movement. However, unlike limb movement, this effect on the final acoustic product of speech may or may not be advantageous, depending on the existing speech profile of individual patients.

OBJECTIVE: To determine (1) the most effective of three treatment approaches to retrain seated weight distribution long-term after stroke and (2) whether improvements could be generalized to weight distribution in standing. SETTING: Inpatient rehabilitation unit. DESIGN: Forty asymmetrical acute stroke subjects were randomly allocated to one of four groups in this pilot study. Changes in weight distribution were compared between the 10 subjects of each of three treatment groups (task-specific reach, Bobath, or Balance Performance Monitor [BPM] feedback training) and a no specific treatment control group. One week of measurement only was followed by two weeks of daily training sessions with the treatment to which the subject was randomly allocated. Measurements were performed using the BPM daily before treatment sessions, two weeks after cessation of treatment and 12 weeks post study. Weight distribution was calculated in terms of mean balance (percentage of total body weight) or the mean of 300 balance points over a 30-s data run. RESULTS: In the short term, the Bobath approach was the most effective treatment for retraining sitting symmetry after stroke (p = 0.004). Training with the BPM and no training were also significant (p = 0.038 and p = 0.035 respectively) and task-specific reach training failed to reach significance (p = 0.26). At 12 weeks post study 83% of the BPM training group, 38% of the task-specific reach group, 29% of the Bobath group and 0% of the untrained group were found to be distributing their weight to both sides. Some generalization of symmetry training in sitting to standing was noted in the BPM training group which appeared to persist long term. CONCLUSIONS: Results should be treated with caution due to the small group sizes. However, these preliminary findings suggest that it might be possible to restore postural symmetry in sitting in the early stages of rehabilitation with therapy that focuses on creating an awareness of body position.

The basal ganglia may be involved in bimanual co-ordination. Parkinson's disease (which impairs basal ganglia output) is clinically reported to cause difficulties in the performance of co-ordinated bimanual movements. Nevertheless, any bimanual co-ordination difficulties may be task specific, as experimental observations are equivocal. To infer the role of the basal ganglia in co-ordinating the two arms, this study investigated the bimanual co-ordination of patients with Parkinson's disease. Sixteen Parkinson's disease patients and matched control subjects performed a bimanual cranking task, at different speeds (1 and 2 Hz) and phase relationships. All subjects performed the required bimanual in-phase movement on a pair of cranks, at fast (2 Hz) and slow (1 Hz) speeds. However, the Parkinson's disease patients were unable to perform the asymmetrical anti-phase movement, in which rotation of the cranks differed by 180 degrees, at either speed; but instead reverted to the in-phase symmetrical movement. For Parkinson's disease patients, performance of the in-phase movement was more accurate and stable when an external timing cue was used; however, for anti-phase movement, the external cue accentuated the tendency for patients to revert to more symmetrical, in-phase movements.

Hypokinetic movement can be greatly improved in Parkinson's disease patients by the provision of external cues to guide movement. It has recently been reported, however, that movement performance in parkinsonian patients can be similarly improved in the absence of external cues by using attentional strategies, whereby patients are instructed to consciously attend to particular aspects of the movement which would normally be controlled automatically. To study the neurophysiological basis of such improvements in performance associated with the use of attentional strategies, movement-related cortical potentials were examined in Parkinson's disease and control subjects using a reaction time paradigm. One group of subjects were explicitly instructed to concentrate on internally timed responses to anticipate the presentation of a predictably timed go signal. Other subjects were given no such instruction regarding attentional strategies. Early-stage premovement activity of movement-related potentials was significantly increased in amplitude and reaction times were significantly faster for Parkinson's disease subjects when instructed to direct their attention toward internally generating responses rather than relying on external cues. It is therefore suggested that the use of attentional strategies may allow movement to be mediated by less automatic and more conscious attentional motor control processes which may be less impaired by basal ganglia dysfunction, and thereby improve movement performance in Parkinson's disease.

PURPOSE: The aim of this study was to examine whether older people are prepared to engage in appropriate falls prevention strategies after discharge from hospital. DESIGN AND METHODS: We used a semi-structured interview to survey older patients about to be discharged from hospital and examined their knowledge regarding falls prevention strategies to utilize in the post-discharge period. The study was part of a prospective cohort study, nested within a larger, randomized controlled trial. Participants (n = 333) were asked to suggest strategies to reduce their falls risk at home after discharge, and their responses were compared with current reported research evidence for falls prevention interventions. RESULTS: Participants' strategies (n = 629) were classified into 7 categories: behavioral, support while mobilizing, approach to movement, physical environment, visual, medical, and activities or exercise. Although exercise has been identified as an effective falls risk reduction strategy, only 2.9% of participants suggested engaging in exercises. Falls prevention was most often conceptualized by participants as requiring 1 (35.4%) or 2 (40.8%) strategies for avoiding an accidental event, rather than engaging in sustained multiple risk reduction behaviors. IMPLICATIONS: Results demonstrate that older patients have low levels of knowledge about appropriate falls prevention strategies that could be used after discharge in spite of their increased falls risk during this period. Findings suggest that health care workers should design and deliver falls prevention education programs specifically targeted to older people who are to be discharged from hospital.

QUESTIONS: What factors are associated with adherence of older adults to group exercise interventions for the prevention of falls? What is the relationship between adherence and the falls prevention efficacy of the intervention? DESIGN: Systematic review with meta-analysis of randomised trials. PARTICIPANTS: Older adults (60 years and older) undertaking a group exercise intervention for falls prevention. INTERVENTION: Group exercise not in combination with a home program and intended at least in part for falls prevention. OUTCOME MEASURES: Adherence was measured as the mean proportion of sessions attended, including participants who discontinued the intervention. Falls prevention efficacy was measured as the proportion of fallers in the intervention versus the control group at follow-up. Various program-related factors, including intervention duration, session frequency, and components of the exercise regimen were examined for each of the studies. RESULTS: Of the 210 articles identified, 18 studies met the inclusion criteria and were analysed. The pooled estimate of adherence across the studies was 0.74 (95% CI 0.67 to 0.80). Lower levels of adherence were associated with group exercise interventions that had a duration of 20 weeks or more, two or fewer sessions per week, or a flexibility component. No significant relationship was found between adherence and falls prevention efficacy. CONCLUSION: Program-related factors may influence adherence to group exercise interventions for the prevention of falls. Further research is encouraged to more precisely determine the effect of intervention level factors on adherence, and the effect of adherence on intervention efficacy.