Asunto(s)

RESUMEN

Purpose To evaluate whether a protocol for early intervention addressing the psychosocial risk factors for delayed return to work in workers with soft tissue injuries would achieve better long-term outcomes than usual (stepped) care. Methods The study used a controlled, non-randomised prospective design to compare two case management approaches. For the intervention condition, workers screened within 1-3 weeks of injury as being at high risk of delayed returned to work by the Örebro Musculoskeletal Pain Screening Questionnaire-short version (ÖMPSQ-SF) were offered psychological assessment and a comprehensive protocol to address the identified obstacles for return to work. Similarly identified injured workers in the control condition were managed under usual (stepped) care arrangements. Results At 2-year follow-up, the mean lost work days for the Intervention group was less than half that of the usual care group, their claim costs were 30% lower, as was the growth trajectory of their costs after 11 months. Conclusions The findings supported the hypothesis that brief psychological risk factor screening, combined with a protocol for active collaboration between key stakeholders to address identified psychological and workplace factors for delayed return to work, can achieve better return on investment than usual (stepped) care.

Asunto(s)

RESUMEN

The original version of this article unfortunately contained a spelling error in one of the co-authors's names. The family name of the co-author was incorrectly displayed as "James McCauley" instead of "James McAuley. The original article has been corrected.

RESUMEN

In recent years, there has been increasing interest in studying causal mechanisms in the development and treatment of back pain. The aim of this article is to provide an overview of our current understanding of causal mechanisms in the field. In the first section, we introduce key concepts and terminology. In the second section, we provide a brief synopsis of systematic reviews of mechanism studies relevant to the clinical course and treatment of back pain. In the third section, we reflect on the findings of our review to explain how understanding causal mechanisms can inform clinical practice and the implementation of best practice. In the final sections, we introduce contemporary methodological advances, highlight the key assumptions of these methods, and discuss future directions to advance the quality of mechanism-related studies in the back pain field.

Asunto(s)

RESUMEN

BACKGROUND: Clinical prediction rules can assist clinicians to identify patients with low back pain (LBP) who are likely to recover quickly with minimal treatment; however, there is a paucity of validated instruments to assist with this task. METHOD: We performed a pre-planned external validation study to assess the generalizability of a simple 3-item clinical prediction rule developed to estimate the probability of recovery from acute LBP at certain time points. The accuracy of the rule (calibration and discrimination) was determined in a sample of 956 participants enrolled in a randomized controlled trial. RESULTS: The calibration of the rule was reasonable in the new sample with predictions of recovery typically within 5-10% of observed recovery. Discriminative performance of the rule was poor to moderate and similar to that found in the development sample. CONCLUSIONS: The results suggest that the rule can be used to provide accurate information about expected recovery from acute LBP, within the first few weeks of patients presenting to primary care. Impact analysis to determine if the rule influences clinical behaviours and patient outcomes is required.

Asunto(s)

RESUMEN

BACKGROUND: Olfactory hallucinations are known to occur in idiopathic Parkinson's disease (IPD) but are much less well-described than visual hallucinations. OBJECTIVE: To report the prevalence, clinical features, response to treatment and prognosis of olfactory hallucinations in IPD. METHODS: 205 consecutively reviewed IPD patients and 205 non-IPD control patients attending the local hospital were surveyed for the presence of olfactory hallucinations by specific questioning; the IPD patients were followed up for at least three years. RESULTS: Of 188 patients who had a clinical course remaining consistent with IPD, four were initially found to have olfactory hallucinations, yielding a prevalence of 2.1% (95% confidence interval 0.4-5.4%). Two further patients developed such hallucinations later during the study. Olfactory hallucinations were not always accompanied by other hallucination modalities. The patients had a long duration of disease treated with dopaminergic medication, loss of sense of smell typical for IPD, no dementia or features suggestive of non-idiopathic PD after three years follow-up, a lack of insight into their hallucinations with consequent failure to report them spontaneously, and a good and lasting response to modest doses of atypical antipsychotics. CONCLUSIONS: This study confirms the significant prevalence of olfactory hallucinations, describes their clinical features and indicates that they may occur in isolation and not predict other psychotic or dementing features. The nuisance that such hallucinations cause, their ease of treatment and their failure to be volunteered as a symptom means that specific questioning for their presence should be included in routine assessment of patients with IPD.

Asunto(s)

Asunto(s)

RESUMEN

OBJECTIVE: Parkinson's disease is a relatively common progressive neurodegenerative disorder, one of whose main features is difficulty with walking. This can be partially corrected by providing cues for the placement of each step. We piloted the potential benefit of simple custom-designed 'walking glasses' worn by the patient that provide visual and auditory cues to aid in step placement. DESIGN: We used a repeated measures design to compare gait performance when unaided and when using the walking glasses with different patterns of visual and auditory stimulation by timing patients' walking over a 'real-life' predefined 30-m course. SETTING: Hospital outpatient clinic. SUBJECTS: Fifteen patients with idiopathic Parkinson's disease who had significant gait problems and no other condition affecting gait performance. MAIN MEASURES: Timed walk. RESULTS: Using the glasses, 8 of 15 patients achieved a significant and meaningful average improvement in walking time of at least 10% (mean (95% confidence interval) improvement in these patients was 21.5% (3.9%)), while a further 2 had subjective and modest objective benefit. Different patterns of visual and auditory cues suited different patients. Visual cueing alone with a fixed horizontal cue line present all the time statistically resulted in the greatest improvement in walking time. CONCLUSIONS: This pilot study shows promising improvement in the gait of a significant proportion of Parkinson's disease patients through the use of a simple, inexpensive and robust design of walking glasses, suggesting practical applicability in a therapy setting to large numbers of such patients.

Asunto(s)

RESUMEN

OBJECTIVE: Estimates of treatment effects reported in placebo-controlled randomized trials are less subject to bias than those estimates provided by other study designs. The objective of this meta-analysis was to estimate the analgesic effects of treatments for non-specific low back pain reported in placebo-controlled randomized trials. METHODS: Medline, Embase, Cinahl, PsychInfo and Cochrane Central Register of Controlled Trials databases were searched for eligible trials from earliest records to November 2006. Continuous pain outcomes were converted to a common 0-100 scale and pooled using a random effects model. RESULTS: A total of 76 trials reporting on 34 treatments were included. Fifty percent of the investigated treatments had statistically significant effects, but for most the effects were small or moderate: 47% had point estimates of effects of <10 points on the 100-point scale, 38% had point estimates from 10 to 20 points and 15% had point estimates of >20 points. Treatments reported to have large effects (>20 points) had been investigated only in a single trial. CONCLUSIONS: This meta-analysis revealed that the analgesic effects of many treatments for non-specific low back pain are small and that they do not differ in populations with acute or chronic symptoms.

Asunto(s)

RESUMEN

The placebo is an important tool to blind patients to treatment allocation and therefore minimise some sources of bias in clinical trials. However, placebos that are improperly designed or implemented may introduce bias into trials. The purpose of this systematic review was to evaluate the adequacy of placebo interventions used in low back pain trials. Electronic databases were searched systematically for randomised placebo-controlled trials of conservative interventions for low back pain. Trial selection and data extraction were performed by two reviewers independently. A total of 126 trials using over 25 different placebo interventions were included. The strategy most commonly used to enhance blinding was the provision of structurally equivalent placebos. Adequacy of blinding was assessed in only 13% of trials. In 20% of trials the placebo intervention was a potentially genuine treatment. Most trials that assessed patients' expectations showed that the placebo generated lower expectations than the experimental intervention. Taken together, these results demonstrate that imperfect placebos are common in low back pain trials; a result suggesting that many trials provide potentially biased estimates of treatment efficacy. This finding has implications for the interpretation of published trials and the design of future trials. Implementation of strategies to facilitate blinding and balance expectations in randomised groups need a higher priority in low back pain research.

Asunto(s)

RESUMEN

Clinical practice guidelines state that the tissue source of low back pain cannot be specified in the majority of patients. However, there has been no systematic review of the accuracy of diagnostic tests used to identify the source of low back pain. The aim of this systematic review was therefore to determine the diagnostic accuracy of tests available to clinicians to identify the disc, facet joint or sacroiliac joint (SIJ) as the source of low back pain. MEDLINE, EMBASE and CINAHL were searched up to February 2006 with citation tracking of eligible studies. Eligible studies compared index tests with an appropriate reference test (discography, facet joint or SIJ blocks or medial branch blocks) in patients with low back pain. Positive likelihood ratios (+LR) > 2 or negative likelihood ratios (-LR) < 0.5 were considered informative. Forty-one studies of moderate quality were included; 28 investigated the disc, 8 the facet joint and 7 the SIJ. Various features observed on MRI (high intensity zone, endplate changes and disc degeneration) produced informative +LR (> 2) in the majority of studies increasing the probability of the disc being the low back pain source. However, heterogeneity of the data prevented pooling. +LR ranged from 1.5 to 5.9, 1.6 to 4.0, and 0.6 to 5.9 for high intensity zone, disc degeneration and endplate changes, respectively. Centralisation was the only clinical feature found to increase the likelihood of the disc as the source of pain: +LR = 2.8 (95%CI 1.4-5.3). Absence of degeneration on MRI was the only test found to reduce the likelihood of the disc as the source of pain: -LR = 0.21 (95%CI 0.12-0.35). While single manual tests of the SIJ were uninformative, their use in combination was informative with +LR of 3.2 (95%CI 2.3-4.4) and -LR of 0.29 (95%CI 0.12-0.35). None of the tests for facet joint pain were found to be informative. The results of this review demonstrate that tests do exist that change the probability of the disc or SIJ (but not the facet joint) as the source of low back pain. However, the changes in probability are usually small and at best moderate. The usefulness of these tests in clinical practice, particularly for guiding treatment selection, remains unclear.

Asunto(s)

RESUMEN

Despite the fact that Parkinson's disease (PD) is a relatively common neurological condition, the physiological derangements that result in its clinical features remain unclear. On combining findings from psychophysical, clinical and electrophysiological studies, an overriding theme is proposed that PD deficits are essentially quantitative rather than qualitative in nature. This may arise because the normal function of the basal ganglia is to activate neural processes selectively, providing appropriate diversion of "attentional" resources for decision-making aspects of motor tasks and appropriate "energising" of the executive aspects of such tasks. It is suggested that these concepts of attention, an idea stemming from psychophysical studies, and of energisation, which has derived from kinematic studies, may in fact reflect the same universal process of selective facilitation of particular processes and inhibition of others. In PD, without efficient facilitation, tasks may still be performed but less well than in normal individuals. Possible underlying mechanisms of basal ganglial function are discussed in the context of new findings on direct and indirect pathway actions and the role that oscillatory modulations may play in achieving selective facilitation is explored. Further investigation of disturbances of such mechanisms in PD may prove important in understanding the underlying pathophysiology of the condition.

Asunto(s)

Asunto(s)

RESUMEN

OBJECTIVES: Although Parkinson's disease is typically characterised by bradykinesia, rigidity, and rest tremor, the possibility that two additional motor deficits are manifest during small hand muscle activity was explored-namely, weakness and abnormal physiological tremor. METHODS: A paradigm previously used in normal subjects reliably records the strength, tremor and surface EMG of index finger abducting contractions against a compliant (elastic) resistance. In addition to the well known physiological tremor at around 10 Hz, there are other co existing peak tremor frequencies at around 20 and 40 Hz; the last of these frequencies corresponds to the range of EMG Piper rhythm. The same technique was used to study parkinsonian patients while on and off dopaminergic medication. RESULTS: The maximum strength of finger abduction produced by first dorsal interosseous contraction was considerably lower when patients were off medication (mean (SD) 6.27 (1.49) N when off v 12.33 (3.64) N when on). There was also a marked reduction in the power of Piper frequency finger tremor (p<0.0005) and EMG (p<0.0005) oscillations that did not simply result from weaker contraction. CONCLUSION: As the components of physiological tremor at higher frequencies are thought to derive from CNS oscillations important in motor control, their loss in parkinsonism in association with severe off symptoms may represent an important pathophysiological link between dopaminergic depletion and parkinsonian motor deficits.

Asunto(s)

RESUMEN

In recent years there has been increasing interest in oscillatory neural activity in the CNS and in the role that such activity may have in motor control. It is thought that physiological tremor may be a manifestation in the periphery of such central oscillatory activity and that some pathological tremors are the result of derangement of these oscillators. This review re-evaluates both early and recent studies on physiological and pathological tremors and other peripheral oscillations in order to gain a new perspective on the nature and function of their central progenitors. This approach, namely using tremor as a 'window' into the function of central oscillations, is particularly suited to human investigations because of the obvious limitations of direct central recording. It is argued that physiological tremor is likely to be multifactorial in origin, with contributions not only from CNS 10-Hz range oscillatory activity, but also from motor unit firing properties, mechanical resonances and reflex loop resonances. Different origins are likely to dominate under different conditions. While some pathological tremors appear to arise as a distortion of central or peripheral components of physiological tremor, others arise de novo, such as the pathological oscillation of 3- to 6-Hz parkinsonian tremor. CNS oscillations outside the 10-Hz range are also found to modulate limb activity in normal individuals, and oscillatory activity exists in other motor systems such as eye movements. Finally, it is shown how studies of peripheral oscillations may help develop hypotheses on the role of CNS oscillations in motor control, including the proposed 'binding' function of synchronized oscillations and the possibility that motor signals could be coded by frequency of modulating oscillation as well as by synaptic connectivity.

Asunto(s)

RESUMEN

Primary orthostatic tremor is characterized by unsteadiness and shakiness of the legs while standing. It is due to a remarkably strong and regular EMG modulation at approximately 16 Hz that is thought to be of CNS origin. Previous studies have shown that the tremor frequency is the same in all involved muscles and that the time relation between bursts of activity in different muscles may be fixed (e.g. always co-contracting or always contracting in an alternating pattern). Here we have used frequency domain analysis of postural muscle EMG signals in five primary orthostatic tremor patients and in two normal controls to explore the nature of such fixed timing patterns. The timing is found not to relate simply to the relative conduction times for passage of rhythmic bursts from a central oscillation to different muscles. Indeed, although the timing pattern (expressed as phase) of the 16-Hz EMG bursts in different postural muscles remains constant while the subject adopts a certain steady posture, it is different for different subjects and also changes when the same subject adopts a different posture. It seems unlikely that such complex task-dependent timing relations of rhythmic postural muscle activity are due to the primary pathology of primary orthostatic tremor. Instead, we suggest that the abnormally strong peripheral manifestation of a 16-Hz CNS oscillation merely unmasks normal central processes so that the timing patterns may provide a clue to the nature of postural motor control.

Asunto(s)

RESUMEN

A hospital-based cross-sectional study examined 657 consecutive referrals with low back pain over two years to a district rheumatology service serving a population of about 250,000 people. Five hundred and thirty-eight had mechanical/degenerative low back pain. The mean age was 48.6 (range 18-80 SD 15.3) years; 64% were women. Patients with radiating pain or neurological deficit (Quebec Task Force classification) were significantly more disabled (Roland disability score p < 0.001) and depressed (Modified Zung score p < 0.05) than those without radiating pain. Women were more impaired (p = 0.02) than men but had similar disabilities (mean Roland score 11.7, range 0-24 SD 6.5). Fifty-three per cent of patients were receiving benefits and were significantly more likely to have musculoskeletal comorbidities than those in work (p < 0.025). It is concluded that the Quebec Task Force classification of low back pain impairment is a helpful descriptor and related to both physical and psychological disability and handicap in employment.

Asunto(s)

RESUMEN

To investigate the possibility that rhythmic activity originating in the central nervous system may modulate human eye movements, anticipatory eye movements were generated by tracking an intermittently obscured sinusoidally moving target. Eight subjects tracked intermittently obscured sinusoids of three different frequencies and of two different amplitudes. Eye movements were recorded by an infra-red reflection technique. The eye velocity records were analysed in the frequency domain by power spectral estimates. During periods where the target was obscured, eye movements consisted of a staggered series of anticipatory saccades with intervening smooth anticipatory eye movements or relatively stationary periods. In sections where the intervening smooth components of anticipatory tracking were of high velocity (above 15 deg/s), a superimposed smooth tremulous oscillation at around 10 Hz was sometimes present. Coherence analysis showed that this 10 Hz range oscillation of smooth anticipatory movement was not derived from head tremor and that the same oscillation was present in both eyes. This oscillation was not generally observed during smooth tracking of pseudorandom waveforms. Investigation of anticipatory eye movements has revealed a 10-Hz range oscillation or "tremor" superimposed upon smooth movements that might in other circumstances be inhibited by direct visual feedback. This smooth eye movement oscillation is thought to originate from the central nervous system and may reflect a widespread frequency modulation of motor commands.

Asunto(s)

Asunto(s)

RESUMEN

1. A 10 Hz range centrally originating oscillation has been found to modulate slow finger movements and anticipatory smooth eye movements. To determine if an interaction or linkage occurs between these two central oscillations during combined visuo-manual tracking, frequency and coherence analysis were performed on finger and eye movements while they simultaneously tracked a visual target moving in intermittently visible sinusoidal patterns. 2. Two different frequencies of common or linked oscillation were found. The first, at 2-3 Hz, was dependent on visual feedback of target and finger tracking positions. The second, at around 10 Hz, still occurred when both target and finger positions were largely obscured, indicating that this common oscillation was generated internally by the motor system independent of visual feedback. Both 3 and 10 Hz oscillation frequencies were also shared by the right and left fingers if subjects used these together to track a visual target. 3. The linking of the 10 Hz range oscillations between the eyes and finger was task specific; it never occurred when eye and finger movements were made simultaneously and independently, but only when they moved simultaneously and followed the target together. However, although specific for tracking by the eyes and fingers together, the linking behaviour did not appear to be a prerequisite for such tracking, since significant coherence in the 10 Hz range was only present in a proportion of trials where these combined movements were made. 4. The experiments show that common oscillations may modulate anatomically very distinct structures, indicating that single central oscillations may have a widespread distribution in the central nervous system. The task-specific manifestation of the common oscillation in the eye and finger suggests that such mechanisms may have a functional role in hand-eye co-ordination.

Asunto(s)