Prevalence Of Dyskinesia Research Articles

Long-Term Follow-Up of the LEAP Study: Early Versus Delayed Levodopa in Early Parkinson's Disease.

The Levodopa in EArly Parkinson's disease study showed no effect of earlier versus later levodopa initiation on Parkinson's disease (PD) progression over 80 weeks. We now report the effects over 5 years. The Levodopa in EArly Parkinson's disease study randomly assigned patients to levodopa/carbidopa 300/75 mg daily for 80 weeks (early start) or to placebo for 40 weeks followed by levodopa/carbidopa 300/75 mg daily for 40 weeks (delayed start). Follow-up visits were performed 3 and 5 years after baseline. We assessed the between-group differences in terms of square root transformed total Unified Parkinson's Disease Rating Scale score at 3 and 5 years with linear regression. We compared the prevalence of dyskinesia, prevalence of wearing off, and the levodopa equivalent daily dose. A total of 321 patients completed the 5-year visit. The adjusted square root transformed total Unified Parkinson's Disease Rating Scale did not differ between treatment groups at 3 (estimated difference, 0.17; standard error, 0.13; P = 0.18) and 5 years (estimated difference, 0.24; standard error, 0.13; P = 0.07). At 5 years, 46 of 160 patients in the early-start group and 62 of 161 patients in the delayed-start group experienced dyskinesia (P = 0.06). The prevalence of wearing off and the levodopa equivalent daily dose were not significantly different between groups. We did not find a difference in disease progression or in prevalence of motor complications between patients with early PD starting treatment with a low dose of levodopa 40 weeks earlier versus 40 weeks later over the subsequent 5 years. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The prevalence of impulsive compulsive behaviors in patients treated with apomorphine infusion: a retrospective analysis.

Impulsive compulsive behaviors (ICBs) can affect a significant number of Parkinson's disease (PD) patients. We have studied brain samples from a brain bank of PD patients who received apomorphine via continuous infusion in life to assess the prevalence and outcome of ICBs. A search on the Queen Square Brain Bank (QSBB) database for cases donated from 2005 to 2016 with a pathological diagnosis of idiopathic PD was conducted. Notes of all donors who used apomorphine via continuous infusion for at least three months were reviewed. Clinical and demographic data were collected, as well as detailed information on treatment, prevalence and outcomes of ICBs. 193 PD cases, 124 males and 69 females, with an average age at disease onset of 60.2 years and average disease duration of 17.2 years were reviewed. Dementia occurred in nearly half of the sample, depression in one quarter, and dyskinesias in a little over 40%. The prevalence of ICBs was 14.5%. Twenty-four individuals used apomorphine infusion for more than three months. Patients on apomorphine had younger age at disease onset, longer disease duration, and higher prevalence of dyskinesias. The prevalence of de novo ICB cases among patients on apomorphine was 8.3%. Apomorphine infusion was used for an average of 63.1 months on an average maximum dose of 79.5 mg per day. Ten patients remained on apomorphine until death. Apomorphine can be used as an alternative treatment for patients with previous ICBs as it has low risk of triggering recurrence of ICBs.

Functional neurological disorders in Parkinson disease

ObjectiveTo ascertain demographic and clinical features of Parkinson disease (PD) associated with functional neurological features.MethodsA standardised form was used to extract data from electronic records of 53 PD patients with...

Levodopa Effect and Motor Function in Late Stage Parkinson's Disease.

It is unclear to which degree Levodopa (L-dopa) remains effective also in the late stage of Parkinson's disease (PD) and to which degree motor fluctuations and dyskinesias remain a problem. To assess responsiveness of motor symptomatology to L-dopa in a group of patients with late stage PD. Moreover, to investigate the extent to which motor fluctuations and dyskinesias occur. Thirty PD patients in Hoehn and Yahr (HY) stages IV and V in "on" were included. L-dopa responsiveness was assessed with a standardized L-dopa test in the defined "off" and defined "on" states. Motor function was assessed by the Unified PD Rating Scale (UPDRS) III and timed tests. Motor fluctuations and dyskinesias were assessed by the UPDRS IV. The participants were further monitored for 10 days with a mobile movement-analyses-system, the Parkinson's Kinetigraph (PKG). The median (q1-q3) L-dopa equivalent daily dose (LEDD) was 799 (536-973) mg. The UPDRS III score improved with ≥15% in 15 (50%) and with ≥30% in six (20%) participants during the L-dopa test. The median (q1-q3) UPDRS III score in "off" was 46 (37-53) and in "on" 36 (28-46). Twenty-one (70%) of the participants reported either predictable or unpredictable "off" fluctuations (items 36-37). The prevalence of dyskinesias (item 32, duration of dyskinesias ≥1) was 47%. The PKG indicated that dyskinesias primarily were mild and that a majority had a pronounced "off" symptomatology, spending a large proportion of the day either asleep or very inactive. Half of a group of patients with late stage PD had an L-dopa response of ≥15% on the UPDRS III. According to the UPDRS IV, a majority of the patients had motor fluctuations and about half had dyskinesias, although the PKG results suggested that these were not very severe.

Dopamine receptors and BDNF-haplotypes predict dyskinesia in Parkinson's disease

ObjectiveDyskinesia is a known side-effect of the treatment of Parkinson's Disease (PD). We examined the influence of haplotypes in three dopamine receptors (DRD1, DRD2 and DRD3) and the Brain Derived Neurotrophic Factor (BDNF) on dyskinesia. MethodsPatient data were drawn from a population-based case-control study. We included 418 patients with confirmed diagnoses by movement disorder specialists, using levodopa and a minimum three years disease duration at the time of assessment. Applying Haploview and Phase, we created haploblocks for DRD1-3 and BDNF. Risk scores for DRD2 and DRD3 were generated. We calculated risk ratios using Poisson regression with robust error variance. ResultsThere was no difference in dyskinesia prevalence among carriers of various haplotypes in DRD1. However, one haplotype in each DRD2 haploblocks was associated with a 29 to 50% increase in dyskinesia risk. For each unit increase in risk score, we observed a 16% increase in dyskinesia risk for DRD2 (95%CI: 1.05–1.29) and a 17% (95%CI: 0.99–1.40) increase for DRD3. The BDNF haploblock was not associated, but the minor allele of the rs6265 SNP was associated with dyskinesia (adjusted RR 1.31 (95%CI: 1.01–1.70)). ConclusionCarriers of DRD2 risk haplotypes and possibly the BDNF variants rs6265 and DRD3 haplotypes, were at increased risk of dyskinesia, suggesting that these genes may be involved in dyskinesia related pathomechanisms. PD patients with these genetic variants might be prime candidates for treatments aiming to prevent or delay the onset of dyskinesia.

Prevalence of wearing-off and dyskinesia among the patients with Parkinson's disease on levodopa therapy: a multi-center registry survey in mainland China.

ObjectiveChronic levodopa (L-dopa) treatment in Parkinson’s disease (PD) is often associated with the development of motor complications, but the corresponding epidemiological data is rare in Chinese PD patients. The present survey was to investigate the prevalence rate of wearing-off (WO) and dyskinesia among the patients with PD in China.MethodsFrom May 2012 to October 2012, a 3-step registry survey for wearing off (WO) and dyskinesia patients with PD receiving levodopa therapy was performed simultaneously at 28 movement disorders clinics in China.ResultsThere were 1,558 PD patients fulfilling the inclusion criteria. Among them, 1,051 had at least one positive response of 9-item wearing off questionnaire (WOQ-9), 724 and 160 patients were finally diagnosed with WO and dyskinesia by movement disorders specialists, respectively. The overall prevalence rates of WO and dyskinesia were 46.5% (95% CI 44.0% - 48.9%) and 10.3% (95% CI 8.8% - 11.8%), respectively. The mean score of WOQ-9 for those with WO was 3.8 (SD = 1.8), with movement slowness being the most common motor symptoms and pain/aching being the most common non-motor symptoms. Better improvement of motor symptoms (n = 354, 87.8%) and long-term disease control and drug selection (n = 288, 71.5%) were the two most frequently considered factors when movement disorders specialists adjusted therapeutic strategies for patients with WO.ConclusionsThis survey provided the first multi-center epidemiological data of motor complications among PD patients on L-dopa therapy from mainland China. WO prevalence rate among Chinese PD patients was in line with, while dyskinesia prevalence rate was lower than previous reports from other Countries.Electronic supplementary materialThe online version of this article (doi:10.1186/2047-9158-3-26) contains supplementary material, which is available to authorized users.

Serotonergic antidepressant drugs and L-dopa-induced dyskinesias in Parkinson's disease.

Serotonergic system is believed to play a role in levodopa-induced-dyskinesias pathogenesis, and serotonin transporter has been evaluated as potential target. To retrospectively investigate the potential effect of selective serotonin reuptake inhibitors (SSRIs) during dopaminergic treatment, in the development of dyskinesias in patients with Parkinson's disease (PD). One hundred and thirty-five consecutive patients with PD, with 10-year follow-up since diagnosis. Age at PD onset, duration of levodopa treatment, maximum daily dose, and SSRIs exposure were collected. Risk, latency, and severity of dyskinesias were evaluated comparing patients with and without SSRIs exposure. Forty-nine patients received SSRIs for a variable period, 86 were never treated; no significant difference between the groups was observed (P=0.897) in the prevalence of dyskinesias. Considering latency between PD diagnosis and dyskinesias onset, patients exposed to SSRIs developed dyskinesias later (6.48±1.99 vs 5.70±1.89years, P=0.020). The median dyskinesia severity score was 0 in the exposed group vs 1 in non-exposed patients (P=0.025). Multivariate analysis demonstrated SSRIs exposure as the only independent predictor, protecting from severe dyskinesia. Use of SSRIs in patients with PD did not protect from dyskinesias; however, exposure may delay the onset and reduce the severity, confirming modulation of the serotonergic system as possible antidyskinetic strategy.

EPA-1792 – Movement disorders in psychiatric emergency: findings from a tunisian cohort of 335 patients

Movement disorders are a frequent finding in psychiatric practice, even in emergency. Studies on acute movement disorders in psychiatric emergency are rare. To determine characteristic features of patients presenting with movement disorders in psychiatric emergency. We conducted a retrospective study over one year period including all patients presenting in psychiatric emergency of Razi Hospital for movement disorders (from October2012 to September2013). Clinical, etiological and therapeutic features were analyzed. We included 335patients consulting in emergency for movement disorders (3.36% of all consultations in psychiatric emergency; sex-ratio: 3.53; mean age of 37.8 years). Main movement disorders (unique or in association) were acute and tardive dyskinesia(40%), Parkinsonian syndrome(34%), tremor(28%), acute dystonia(16.2%) (Mainly torticolis(22%), orofacial dystonia(17%)), akathisia(5.7%), oculogyric crisis(2.4%). Only one patient presented with neuroleptic malignant syndrome. Etiologies were mostly iatrogenic causes (drug abuse, weaning, errors, incomplinace). Most of patients had chronic psychosis (38.5%); 6.8% had simulated mevement disorders and 3.9% hysterical conversions. Anticholinergics (Trihexyphenidyle chlorhydrate in 64.5%) and benzodiazepines(14.3%) were the most used drugs in emergency. Only 3.9% of patients were admitted in hospitalization in emergency. Our series shows the relative frequency (>3%) of movement disorders as a chief complaint in psychiatric emergency. The predominance of young male adults may be explained by the higher prevalence of dyskinesias in our series, for which younger age and masculine sex are risk factors. It is necessary to distinguish authentic movement disorders from psychogenic ones and simulations to avoid abusive prescriptions of anticholinergics, often explicitly claimed by simulators.

Association of common genetic variants of HOMER1 gene with levodopa adverse effects in Parkinson’s disease patients

Levodopa is the most effective symptomatic therapy for Parkinson's disease, but its chronic use could lead to chronic adverse outcomes, such as motor fluctuations, dyskinesia and visual hallucinations. HOMER1 is a protein with pivotal function in glutamate transmission, which has been related to the pathogenesis of these complications. This study investigates whether polymorphisms in the HOMER1 gene promoter region are associated with the occurrence of the chronic complications of levodopa therapy. A total of 205 patients with idiopathic Parkinson's disease were investigated. Patients were genotyped for rs4704559, rs10942891 and rs4704560 by allelic discrimination with Taqman assays. The rs4704559 G allele was associated with a lower prevalence of dyskinesia (prevalence ratio (PR)=0.615, 95% confidence interval (CI) 0.426-0.887, P=0.009) and visual hallucinations (PR=0.515, 95% CI 0.295-0.899, P=0.020). Our data suggest that HOMER1 rs4704559 G allele has a protective role for the development of levodopa adverse effects.

Risk factors in development of motor complications in Chinese patients with idiopathic Parkinson’s disease

Motor complications induced by levodopa (L-dopa) treatment in Parkinson’s disease (PD) are not well documented in patients of Chinese ethnicity. We performed a cross-sectional study to investigate the prevalence of dyskinesias and motor fluctuations, and the factors determining their development, in a population of Chinese patients with PD. Among 137 patients with PD, 98 (71.5%) had received a L-dopa preparation. Motor fluctuations were found in 74.5% and dyskinesias in 77.6% of the 98 patients. Patients with dyskinesias were younger at onset of disease than those without. Patients with dyskinesias and motor fluctuations had significantly longer duration of PD and L-dopa treatment, higher daily doses of L-dopa, and higher scores in the 39-item Parkinson’s Disease Questionnaire (PDQ-39), when compared to patients without motor complications. Among these factors, motor fluctuations were best predicted by duration of L-dopa treatment and dyskinesias by disease duration. We conclude that motor complications are closely related to disease and treatment parameters, especially the treatment and disease duration.

Fourteen-year final report of the randomized PDRG-UK trial comparing three initial treatments in PD

Ten-year follow-up results from the Parkinson's Disease Research Group of the United Kingdom trial demonstrated that there were no long-term advantages to initiating treatment with bromocriptine compared with l-dopa in early Parkinson disease (PD). Increased mortality in patients on selegiline combined with l-dopa led to premature termination of this arm after 6 years. Between 1985 and 1990, 782 patients were recruited into an open pragmatic multicenter trial and were randomized to l-dopa/decarboxylase inhibitor (DDCI), l-dopa/DDCI plus selegiline, or bromocriptine. The main endpoints were mortality, disability, and motor complications. For final follow-up, health-related quality of life and mental function were also assessed. Median duration of follow-up at final assessment was 14 years in the 166 (21%) surviving participants who could be contacted. After adjustment for baseline characteristics, disability scores were better in the l-dopa than in the bromocriptine arm (Webster: 16.6 vs 19.8; p = 0.03; Northwestern University Disability: 34.3 vs 30.0, p = 0.05). Physical functioning (difference 20.8; 95% CI 10.0, 31.6; p < 0.001) and physical summary scores (difference 5.2; 95% CI 0.7, 9.7; p = 0.03) on the 36-item short-form health survey were also superior on l-dopa. Differences in mortality rates and prevalence of dyskinesias, motor fluctuations, and dementia were not significantly different. Initial treatment with the dopamine agonist bromocriptine did not reduce mortality or motor disability and the initially reduced frequency in motor complications was not sustained. We found no evidence of a long-term benefit or clinically relevant disease-modifying effect with initial dopamine agonist treatment.

Tardive dyskinesia and new antipsychotics

To provide an update on tardive dyskinesia rates in patients treated with first-generation or second-generation antipsychotics in studies published since the last systematic review in 2004. Across 12 trials (n = 28 051, age 39.7 years, 59.7% male, 70.9% white, followed for 463 925 person-years), the annualized tardive dyskinesia incidence was 3.9% for second-generation antipsychotics and 5.5% for first-generation antipsychotics. Stratified by age, annual tardive dyskinesia incidence rates were 0.35% with second-generation antipsychotics in children, 2.98% with second-generation antipsychotics versus 7.7% with first-generation antipsychotics (P < 0.0001) in adults, and 5.2% with second-generation antipsychotics versus 5.2% with first-generation antipsychotics (P = 0.865) in the elderly (based almost exclusively on one retrospective cohort study). In four adult studies (n = 2088, age 41.2 years, 71.2% male, 62.0% white), tardive dyskinesia prevalence rates were 13.1% for second-generation antipsychotics, 15.6% for antipsychotic-free patients, and 32.4% for first-generation antipsychotics (P < 0.0001). Current evidence supports a lower tardive dyskinesia risk for second-generation antipsychotics than for first-generation antipsychotics. Tardive dyskinesia incidence was higher with second-generation antipsychotics than previously reported, possibly due to recent studies with relatively short mean durations and use of nonstandard tardive dyskinesia definitions.

The Management Approaches to Dyskinesia Vary from Country to Country

Many Parkinson’s disease (PD) patients treated with levodopa develop motor fluctuations and/or dyskinesia. This large, retrospective study was conducted to compare the prevalence and treatment of dyskinesia in PD patients in seven countries. A total of 380 physicians were interviewed and completed patient record forms retrospectively for their last 5 patients with dyskinesia (total 1,900). The overall prevalence of dyskinesia in PD patients was 34%, but the rate varied from 24 to 51% according to geographical location. This study showed that 51.0% of Japanese physicians and 50.6% of UK physicians were dissatisfied with current treatment strategies for dyskinesia. Regardless of geographical location, physicians were dissatisfied with the current treatment strategies for dyskinesia.

2.249 Investigation on the prevalence of dyskinesia following the switch from pulsatile rotigotine or L-DOPA to continuous rotigotine

2.249 Investigation on the prevalence of dyskinesia following the switch from pulsatile rotigotine or L-DOPA to continuous rotigotine

Relationship of extrapyramidal symptoms to age at onset and drug treatment in middle-aged and elderly schizophrenic patients

The relationship between antipsychotic drugs and dyskinesias and other extrapyramidal symptoms (EPS) in schizophrenia is not simple. There is a need to study variables that may influence the occurrence of EPS in schizophrenic patients receiving drugs. The present study examined the relationship of age at onset of illness and treatment to the development of EPS in 122 middle-aged and elderly schizophrenic patients, 84 treated and 38 who had never received antipsychotic drugs. The illness had an early onset (before 45 years, EOS) in 68 patients and a late onset (after 45 years, LOS) in 54 patients. The patients were evaluated for dyskinesia and parkinsonism using abnormal involuntary movements scale (AIMS) and Simpson–Angus scale. The prevalence of dyskinesia and parkinsonism was similar in all the patient groups. The scores on limb-axial and severity subscales of AIMS were significantly higher in the treated than the untreated patients of the early onset group. This was not so with the late onset patients. The total parkinsonism score was higher among the treated, notably the LOS patients. The development of dyskinesia and parkinsonism in schizophrenia is possibly related to the age at onset of the illness. In late onset forms the ageing of the patient and a possible neurological abnormality related to schizophrenia might enhance the EPS-inducing effect of drugs.

Dyskinesias and motor fluctuations in Parkinson's disease. A community-based study.

We investigated the prevalence of dyskinesias and motor fluctuations, and the factors determining their occurrence, in a community-based population of patients with Parkinson's disease. Among 124 patients with Parkinson's disease, 87 (70%) had received a levodopa preparation. Among these 87 patients, 28% were experiencing treatment-induced dyskinesias and 40% response fluctuations. The prevalence of motor fluctuations was best predicted by disease duration and dose of levodopa, whereas dyskinesias could be best predicted by duration of treatment. Patients with a shorter time from symptom onset to initiation of levodopa and younger patients had developed motor complications earlier, and patients who had started treatment with a dopamine agonist had developed these treatment complications later. Although a satisfactory response to medication was associated with higher rates of motor complications, poor or moderate response was associated with lower quality of life in patients with a disease duration of </=5 years or >/=10 years. We conclude that motor fluctuations are most strongly related to disease duration and dose of levodopa, and dyskinesias to duration of levodopa treatment. However, poorer quality of life associated with inadequate dosage of levodopa may be the price for a low rate of motor complications in patients with Parkinson's disease.

Pergolide for levodopa-induced complications in Parkinson's disease.

To compare the efficacy and safety of adjunct pergolide therapy versus placebo in patients with Parkinson's disease suffering from the complications of levodopa therapy. Electronic searches of MEDLINE, EMBASE and the Cochrane Controlled Trials Register. Handsearching of the neurology literature as part of the Cochrane Movement Disorders Group's strategy. Examination of the reference lists of identified studies and other reviews. Contact with Eli Lilly and Company Limited. Randomised controlled trials of pergolide versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease and long-term complications of levodopa therapy. Data was abstracted independently by each author and differences settled by discussion. The outcome measures used included Parkinson's disease rating scales, levodopa dosage, 'off' time measurements and the frequency of drop outs and adverse events. A large number of small RCTs were identified, but these were part of a large multicentre trial which was eventually published in full. The final publication was used as the only subject for this review. The time patients spent 'off' was reduced by 1.8 hours with pergolide compared with 0.2 hours with placebo (p < 0.001). Dyskinesia developed or deteriorated in 62% of pergolide-treated compared with 25% placebo-treated patients (p < 0. 05). The excess in dyskinesia prevalence and severity resolved by the end of the study with levodopa reduction. Levodopa dose was reduced more in those receiving pergolide (235 mg v 51 mg; p < 0. 001). Pergolide produced significant improvement in Hoehn and Yahr stage (p < 0.05) and both the motor and activities of daily living parts of a modified Columbia rating scale (both p < 0.001). Significantly more patients suffered nausea (24% v 13%; p < 0.001) and hallucinations (14% v 3%; p < 0.01) on pergolide. No difference was found in the numbers remaining on treatment at the end of the study (pergolide 84% v placebo 82%) but withdrawals due to adverse events were greater in those taking pergolide (10% v 4%). Based on this single large multicentre study, pergolide reduces 'off' time and improves impairment and disability due to Parkinson's disease whilst allowing a reduction in levodopa dose. This is at the expense of dopaminergic adverse events. Further trials are required to compare pergolide with the newer dopamine agonists.

The brain hallucinates and gets caught in the web

In the past year, we had a remarkable glimpse of brain activity during hallucination in a patient with schizophrenia (Silbersweig; figure). In his typical hallucination, a patient saw moving, coloured scenes with rolling, disembodied heads, which were giving him instructions. 150 positron emission tomography and an image-analysis protocol, designed to image transient subjective experiences, illustrated which areas had increased regional cerebral blood flow during the hallucinations. Increased brain activity was noted in visual and auditory-associated cortices, as well as paralimbic and subcortical areas. Such studies provide clues to the pathophysiology of schizophrenia and to the neural substrate of conscious perceptual experience. Fascinating new clues to schizophrenia also emerged on the genetics/epidemiology front. Gorwood and colleagues tested the hypothesis that the age of onset of schizophrenia decreases in successive generations. This inheritance pattern, anticipation, results from unstable trinucleotide repeat DNA sequences at the disease locus. The study took place on an island in the Indian Ocean and was based on 97 patients with schizophrenia belonging to 24 families with at least two generations of patients. In the younger generation, the age of onset was significantly less than the expected age of onset based on the data from the older generation. This evidence could accelerate the search for pathological genetic processes implicated in schizophrenia. Psychiatrists are concerned about the potential iatrogenic effects of typical antipsychotics, which are linked to tardive dyskinesia. These effects may be relieved by the findings of McCreadie and colleagues. Dyskinesia was assessed in four groups of elderly individuals including normal people, relatives of schizophrenics, nevermedicated patients with schizophrenia, and medicated patients. The prevalence of dyskinesia was similar in never-medicated and medicated patients (about 40%), and was significantly higher than that in first-degree relatives and normal controls (15%). McCreadie reported that never-medicated patients had classic tardive dysthinesia, including chewing movements, tongue protrusion, lip smacking, and writhing. The researchers conclude that it is the illness per se that is associated with dyskinesias in elderly schizophrenic patients. However, psychiatrists may be chagrined by the work of Mojtabai and Nicholson. These researchers evaluated the inter-rater reliability of ratings of delusions and bizarre hallucinations among 50 psychiatrists selected randomly from the American Psychiatry Association Membership Directory. The inter-rater reliability estimates were quite low (K about 0-40), and call into question the adequacy of psychiatric training.

Dyskinesia in mentally handicapped women: relationship to level of handicap, age and neuroleptic exposure.

The prevalence of dyskinesia in a randomly selected set of 61 mentally handicapped women with a range of diagnoses, levels of IQ and exposure to neuroleptics was assessed using the Abnormal Involuntary Movements Scale (AIMS). Overall, 64% of patients had dyskinesia on the AIMS. There was no correlation with neuroleptic exposure, although 43% of patients had been significantly exposed. There was no correlation between the presence of dyskinesia and the original handicapping diagnosis, and there was no increase in dyskinesia as the patients age increased. There was a significant increase in dyskinesia as IQ fell. This study backs the contention that there is a close association between cognitive impairment and movement disorder.

Prevalence of tardive dyskinesia in samples of elderly people in Hong Kong.

The prevalence of dyskinesia was studied in 4 samples of elderly Chinese people in Hong Kong--a psychogeriatric clinic, a mental hospital, a geriatric day hospital and a senior citizen centre. Research Diagnostic Criteria were used to identify cases of tardive dyskinesia. The overall prevalence of spontaneous dyskinesia was 2.4% and tardive dyskinesia was 25.9%. The rate of spontaneous dyskinesia differs across the study samples and is related to nervous system conditions associated with increased age. On the other hand, the rate of dyskinesia associated with antidepressants may not be significantly different from that of spontaneous dyskinesia.