Systematic evaluation of rating scales for impairment and disability in Parkinson's disease.

We assessed the clinometric characteristics of rating scales used for the evaluation of motor impairment and disability of patients with Parkinson's disease (PD), conducting a systematic review of PD rating scales published from 1960 to the present. Thirty studies describing clinometrics of 11 rating scales used for PD were identified. Outcome measures included validity (including factor structure), reliability (internal consistency, inter-rater, and intrarater) and responsiveness. We traced three impairment scales (Webster, Columbia University Rating Scale [CURS] and Parkinson's Disease Impairment Scale), four disability scales (Schwab and England, Northwestern University Disability Scale [NUDS], Intermediate Scale for Assessment of PD, and Extensive Disability Scale), and four scales evaluating both impairment and disability (New York University, University of California Los Angeles, Unified Parkinson's Disease Rating Scale [UPDRS], and Short Parkinson Evaluation Scale). The scales showed large differences in the extent of representation of items related to signs considered responsive to dopaminergic treatment or to those signs that appear late in the disease course and lack responsiveness to treatment. Regardless of the scale, there was a conspicuous lack of consistency concerning inter-rater reliability of bradykinesia, tremor, and rigidity. Overall disability items displayed moderate to good inter-rater reliability. The available evidence shows that CURS, NUDS, and UPDRS have moderate to good reliability and validity. In contrast to their widespread clinical use for assessment of impairment and disability in PD, the majority of the rating scales have either not been subjected to an extensive clinometric evaluation or have demonstrated clinometric shortcomings. The CURS, NUDS, and UPDRS are the most evaluated, valid, and reliable scales currently available.     

Evaluation of Parkinson's disease: reliability of three rating scales

We studied the three most commonly used rating scales in Parkinson's Disease (Hoehn and Yahr Clinical Staging, Webster Rating Scale, Columbia University Rating Scale) in order to examine the agreement between observers. Six neurologists, experts at using such scales, evaluated 48 patients suffering from the idiopathic form of Parkinson's Disease. Reliability using the K index was moderate, although a slight superiority was found with the Columbia University Rating Scale. Analysis of the various items used has suggested that scales of disability could be a valid alternative to those examined.     

Evaluation of Parkinson's disease: a new approach to disability.

Testing the reliability and usefulness of disability scales in Parkinson's disease has been the object of a study carried out by 4 neurologists on 48 patients using 2 rating scales--Hoehn and Yahr staging and Columbia University Rating Scale--and 2 disability scales--Northwestern University Disability Scale and Extensive Disability Scale, a new scale conceived for this purpose, which is more accurate in examining in a different way the physical incapacity and handicap of parkinsonian patients in their daily living. The examiners worked in pairs and did not discuss their rating scores before the end of the study. As far as interobserver agreement is concerned, the results of the disability scales are better than those of the rating scales. The Northwestern Disability Scale and the new scale are similar in reliability and consistency; however, the Extensive Disability Scale has proved to be a better indicator of the functional status. We suggest a more extensive employment of disability scales in clinical studies.     

Minimal clinically important change on the unified Parkinson's disease rating scale.

The Unified Parkinson's Disease Rating Scale (UPDRS) is the main outcome measure in clinical trials of Parkinson's disease (PD). The minimal change that represents a clinically meaningful improvement is unknown. The objective of this study was to determine the minimal change on the UPDRS that represents a clinically meaningful improvement in early PD after 6 months of treatment. Data from two independent randomized treatment trials over 6 months involving 603 patients with de novo PD were analyzed to determine the minimal clinically important change (MCIC), referred to the status before treatment, for the UPDRS motor, activities of daily living (ADL), and total scores. An anchor-based method using ratings on a seven-point global clinical improvement was used. A change of five points on the UPDRS motor part was found to be the most appropriate cutoff score for all Hoehn and Yahr stages I to III, and a change of eight points for the UDPRS total score. For the UDPRS ADL score, an MCIC of two points for Hoehn and Yahr stages I/I.5 and II and of three points for Hoehn and Yahr stage II.5/III was the most appropriate cutoff score. These data give the first estimate for cutoffs defining clinically important changes in UPDRS ADL and motor scores. Further studies using larger databases from more diverse study populations are encouraged to better define and solidify the MCIC for the UPDRS.     

The relationship of pain and health-related quality of life in Korean patients with Parkinson's disease

Background – Parkinson’s disease (PD) is a chronic progressive neurodegenerative disorder. Increasing attention has been focused on the pain and health‐related quality of life (HrQOL) in patients with PD. Objective – To evaluate the relationship between pain and the HrQOL in patients with PD. Methods – Eighty‐two patients with PD were included and classified into two groups according to the presence of pain. The Hoehn and Yahr scale, the Unified Parkinson’s Disease Rating Scale (UPDRS), the Modified Somatic Perception Questionnaire (MSPQ), the Zung Depression Inventory – Self‐rating Depression Scale (SDS), the Visual Analogue Scale and the Medical Outcomes Study 36‐Item Short Form Health Survey (SF‐36) were administered. The factors influencing the pain, HrQOL and parkinsonian manifestations were evaluated. Results – The PD with pain group had higher UPDRS part III scores, lower SF‐36 scores, higher SDS scores and higher MSPQ scores than the PD without pain group. The presence of pain, high Hoehn and Yahr stage, advanced age and somatic perception were the factors that had a negative effect on the physical component of the HrQOL. Depression and somatic perception were the most important predictive factors for the mental component of the HrQOL. Depression and poor parkinsonian motor abilities were the leading factors contributing to pain. Conclusion – Pain and depression were major detrimental factors affecting the physical and mental aspects of the HrQOL respectively. Therefore, the treatment of pain and depression can be important to improve the HrQOL.     

Bilateral subthalamic nucleus stimulation for Parkinson's disease

High frequency stimulation of the subthalamic nucleus (STN) is known to ameliorate the signs and symptoms of advanced Parkinson's disease. AIM: We studied the effect of high frequency STN stimulation in 23 patients. METHOD: Twenty-three patients suffering from severe Parkinson's disease (Stages III-V on Hoehn and Yahr scale) and, particularly bradykinesia, rigidity, and levodopa-induced dyskinesias underwent bilateral implantation of electrodes in the STN. Preoperative and postoperative assessments of these patients at 1, 3, 6 and 12 months follow-up, in "on" and "off" drug conditions, was carried out using Unified Parkinson's Disease Rating Scale, Hoehn and Yahr staging, England activities of daily living score and video recordings. RESULTS: After one year of electrical stimulation of the STN, the patients' scores for activities of daily living and motor examination scores (Unified Parkinson's Disease Rating Scale parts II and III) off medication improved by 62% and 61% respectively (p<0.0005). The subscores for the akinesia, rigidity, tremor and gait also improved. (p<0.0005). The average levodopa dose decreased from 813 mg to 359 mg. The cognitive functions remained unchanged. Two patients developed device-related complications and two patients experienced abnormal weight gain. CONCLUSION: Bilateral subthalamic nucleus stimulation is an effective treatment for advanced Parkinson's disease. It reduces the severity of "off" phase symptoms, improves the axial symptoms and reduces levodopa requirements. The reduction in the levodopa dose is useful in controlling drug-induced dyskinesias.     

Parkinson’s Disease Sleep Scale 2: application in an Italian population

Sleep disturbances and nocturnal disabilities are common in Parkinson’s Disease (PD). The PD sleep scale, second version (PDSS-2), has been proposed as a helpful tool for measuring sleep disorders in PD. We aimed to validate the Italian version of the PDSS-2. One hundred and twenty-three consecutive PD outpatients (76 males) were evaluated by means of PDSS-2, Epworth Sleepiness Scale, Hamilton Depression Rating Scale, Parkinson’s Disease Quality of Life Questionnaire (self-administered scales), Unified Parkinson’s Disease Rating (motor section) and Hoehn and Yahr Scales, and Mini Mental State Examination. PDSS-2 internal consistency was satisfactory (Cronbach’s α: 0.77) with significant item to total score correlation and high intra-class correlation coefficient for test–retest reliability (0.943). Total PDSS-2 score was correlated with the scores on all other clinical scales. The factor analysis identified five factors, related to five areas of nocturnal disturbances, similarly as the original PDSS-2. The five factors mainly reflected: (1) nocturnal movement-related problems, (2) quality of sleep, (3) dreaming distress, (4) fragmentation of sleep and (5) insomnia symptoms. The PDSS-2 scale has confirmed its usefulness in evaluating sleep problems in Italian PD patients.     

Rapid eye movement sleep behaviour disorder in young- and older-onset Parkinson disease: a questionnaire-based study

BackgroundRapid eye movement sleep behavior disorder (RBD) is common in Parkinson disease (PD).ObjectivesTo determine the frequency of clinically probable RBD (cpRBD) in young-onset (21 to ⩽40 years; YOPD) and older-onset PD (>40 years; OOPD) and characterize its pattern.MethodsA total of 156 patients with PD (YOPD-51, OOPD-105) were clinically examined and the presence of RBD was diagnosed using the minimal criteria for diagnosis of RBD (International Classification of Sleep Disorders, ICSD-1). RBD screening questionnaire based on the minimal criteria was used. The bed-partners were also interviewed with Mayo sleep questionnaire. Other scales included Unified Parkinson Disease Rating Scale part III (UPDRS III), Hoehn & Yahr stage, Mini Mental Status Examination, Pittsburgh Sleep Quality Index, Parkinson Disease Sleep Scale, Epworth Sleep Scale, Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale.ResultscpRBD was diagnosed in 30 (19.2%) patients, majority being OOPD rather than YOPD (86.7% vs 13.3%; P = 0.01). The frequency of RBD was significantly higher (P = 0.016) in OOPD (24.8%) compared to those with YOPD (7.8%). Most often (72.4%) RBD occurred after the onset of parkinsonian symptoms. RBD was independently associated with higher global PSQI scores, total ESS scores and total PDSS scores after adjusting for the effects of age, gender, Hoehn & Yahr stage and duration of illness.ConclusionsPatients with RBD were older with later-onset motor symptoms, a more advanced stage, poorer sleep quality, and more frequent daytime sleepiness. Older-onset PD had a higher frequency of RBD than young-onset PD.     

Observational study of sleep-related disorders in Italian patients with Parkinson’s disease: usefulness of the Italian version of Parkinson’s disease sleep scale

Sleep disturbances are common in patients with Parkinson's disease (PD). We aimed to evaluate prevalence and severity of nighttime sleep disturbances in Italian PD patients and to validate the Italian version of the Parkinson's disease sleep scale. A total of 221 PD patients and 57 healthy controls participated in a cross-sectional study with retest. PDSS, Epworth Sleepiness Scale (ESS), Hamilton Depression Rating Scale, Unified Parkinson's Disease Rating Scale (UPDRS), and Hoehn and Yahr staging were applied. PDSS total and individual items scores from patients were significantly lower than those in controls. Internal consistency of PDSS scale was satisfactory and intraclass correlation coefficient for test-retest reliability was 0.96 for total PDSS score. A significant negative correlation was found between total PDSS and ESS scores, and between total PDSS and HDRS scores. PDSS scores were also related to UPDRS sections II, III and IV, and H&Y stage. PDSS and ESS scores were not related to levodopa equivalent dose. Daytime sleepiness, depressive symptoms and disease severity correlate with sleep disturbances in Italian PD patients. The PDSS is a valid and reliable tool to evaluate sleep disturbances in Italian patients.     

Pallidotomy and quality of life in patients with Parkinson's disease: an early study.

The purpose of this study was to analyze the effect of stereotactic neurophysiologically guided pallidotomy on health-related quality of life (QoL) of patients with Parkinson's disease (PD). Eleven patients with PD (seven men, four women; mean age, 57.2 years; mean duration of disease, 14 years) with motor complications refractory to medical therapy underwent unilateral pallidotomy. Clinical assessment was carried out a week before surgery and 4 months after the surgical procedure and was based on the Core Assessment Program for Intracerebral Transplantations protocol. QoL was measured by means of the PDQ-39. A set of rating scales (Hoehn & Yahr, Unified Parkinson's Disease Rating Scale, Schwab and England, Northwestern University Disability Scale of Walking, Abnormal Involuntary Movement Scale), timed tests, and self-evaluations of motor function and mood were applied. Improvement was found in dyskinesias (74%) and off-period disability (42%). Cardinal motor signs improved significantly (30%-59%). Four dimensions of the PDQ-39 (Mobility, ADL, Emotions, Bodily Pain) showed a significant improvement (p <0.01-0.001). The global effect on QoL, measured through the PDQ-39 Summary Index (35.3%; 95% confidence interval: 15.60-54.97), was also significant (p<0.01) but unrelated to major clinical changes. Pallidotomy significantly improves QoL in patients with advanced PD. QoL measurement provides relevant information that is probably not attainable by clinical assessment.     

Echogenicity of the substantia nigra in Parkinson's disease and its relation to clinical findings

Recently an increased echogenicity of the substantia nigra (SN) in patients with Parkinson's disease (PD) was demonstrated by transcranial ultrasound (TCS). In this study we set out to compare SN echogenicitiy with disease characteristics (time of onset, duration, toxin exposure) in a large patients sample. Patients' history and exposure to toxins were recorded from 112 PD patients who underwent a thorough neurological examination including assessment of disease stage according to Hoehn and Yahr and CURS (Columbia University Rating Scale). Personality was assessed according to the Freiburg Personality Inventory. In all patients the area of SN echogenicity was encircled and measured by TCS. All except 9 patients had hyperechogenic SN areas exceeding the mean plus standard deviation values of an age matched control group (0.19cm²). The age of disease onset was lower in patients who displayed an area of SN echogenicity above this value. The area of SN echogenicity was larger contralateral to the side with more severe symptoms. None of the other characteristics correlated with ultrasound findings. We conclude that SN hyperechogenicity is a typical finding in PD. The cause of hyperechogenicity is so far unknown. Investigation of the underlying reason might disclose a pathogenic factor in PD. Received: 13 November 2000 / Received in revised form: 24 January 2001 / Accepted: 19 February 2001     

(123)I]beta-CIT SPECT imaging demonstrates reduced density of striatal dopamine transporters in Parkinson's disease and multiple system atrophy.

In vivo imaging of the dopamine transporter (DAT) with single photon emission computed tomography (SPECT) is a quantitative biomarker for Parkinson's disease (PD) onset and severity. This study has examined and compared the loss of striatal DAT in PD and multiple system atrophy (MSA) using [(123)I]beta-CIT SPECT imaging. One hundred and eighty-three patients (157 PD and 26 MSA) were studied. Clinical rating scales (Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale [UPDRS] scores) demonstrated that the MSA patients were more severely impaired than the PD patients. The striatal [(123)I]beta-CIT SPECT uptake was markedly reduced in both the PD and MSA groups. In addition, MSA patients showed more symmetric DAT loss compared with the PD patients, consistent with the more symmetric clinical motor dysfunction observed in MSA. While the loss of DAT was significantly reduced in all regions in both MSA and PD, comparison of the relative loss of the DAT did not significantly improve diagnostic accuracy in distinguishing between PD and MSA.     

重复经颅磁刺激治疗帕金森病

目的探讨重复经颅磁刺激对帕金森病患者的治疗作用。方法采用重复经颅磁刺激方法对8例帕金森病患者进行治疗,另选择7例帕金森病患者作为对照。采用改进的H&Y(HoehnandYahr)评分标准、SchwabandEngland日常生活能力评分量表以及帕金森病症状评分量表(UPDRS)进行疗效评估。结果8例接受重复经颅磁刺激治疗的患者,于治疗第3、6和9个月时进行H&Y评分和UPDRS评分,与治疗前相比,这两种评分均明显下降(P<0.05),而SchwabandEngland日常生活能力评分则明显提高,治疗前后相比差异具有显著性意义(P<0.05);对照组治疗前后相比差异无显著性意义(P>0.05)。结论重复经颅磁刺激有助于缓解帕金森病患者的症状。     

The interlocking finger test in patients with Parkinson’s disease and healthy subjects

The interlocking finger test (ILFT) is a bedside screening test in which the subject must imitate four bimanual finger gestures without symbolic meaning. We assessed the utility of the test in the cognitive evaluation of patients with Parkinson’s disease (PD). We evaluated 88 healthy subjects and 101 patients with PD using a simplified motor score of the Unified Parkinson’s Disease Rating Scale (UPDRS), Hoehn and Yahr and Schwab and England scales, Geriatric Depression Scale, Pfeffer Functional Activities Questionnaire, Clinical Dementia Rating, Mini-Mental State Examination, clock drawing test, digit span, word list battery of the Consortium to Establish a Registry for Alzheimer’s Disease assessment, Frontal Assessment Battery, semantic verbal fluency test, and the ILFT. Diagnoses of mild cognitive impairment and dementia were made using the Movement Disorder Society diagnostic criteria. ILFT scores in healthy subjects correlated significantly with age (p = 0.001) and only one healthy subject scored 2 in the test. ILFT scores were significantly lower in patients with PD and dementia (p = 0.001) and significantly correlated with cognitive and functional tests, but not with depressive symptoms (p = 0.607), Hoehn and Yahr scores (p = 0.907), or Schwab and England scores (p = 0.701). Twenty-five patients with dementia, three patients with mild cognitive impairment, and six patients with apparently normal cognition scored less than 3 in the ILFT. The area under the receiver operating characteristic curve for the ILFT to discriminate patients with dementia from those without it was 0.76 (cut-off score of 3/2: sensitivity of 61%, specificity of 0.85). In conclusion, the ILFT seems to be a useful bedside test to assess cognitive impairment in patients with PD.     

Social support plays a role in depression in Parkinson's disease: a cross-section study in a Chinese cohort

To investigate the association between social support and depression in Parkinson's disease (PD), 121 PD patients were enrolled in our study. Interview of questionnaires and neurological examinations, including Hamilton Depression Rating Scale, Chinese Social Support Rating Scale (SSRS), Hoehn and Yahr Stage, Schwab and England Scale (SE) and unified PD Rating Scale (UPDRS) were performed. Increased level of UPDRS and lowered social support were associated with depression in PD patients. Stepwise regression analysis showed that objective social support, UPDRS part 1 and duration of disease manifested significant correlation to patients' depression degree. Therefore, social support plays an important role in depression in PD.     

Body composition in Parkinson's disease: a study with dual-energy X-ray absorptiometry

Some investigators have reported that patients with Parkinson's disease (PD) tend to lose weight, and have a low body mass index. For this reason, it was suggested that PD patients have an increased metabolic rate. Using dual-energy X-ray absorptiometry (DXA) we determined, the body composition in 52 unselected PD patients (28 males, 24 females) and in 80 age and sex-matched healthy controls (40 males, 40 females). The mean+/-SD duration of PD was 5.9+/-4.8 years. PD severity was assesed with the Unified PD Rating Scale (UPDRS) and Hoehn & Yahr staging. PD patients and controls did not differ significantly in height, weight and body mass index. The total fat and percentage of fat were significantly higher (p<0.01) and the lean body mass and water content were lower (p<0.001 for each) in male PD patients when compared with male controls. All these values were similar in female PD patients and female controls. Fat mass, lean body mass and water content did not correlate with the UPDRS scores and Hoehn &Yahr staging, although PD patients with higher UPDRS scores had higher percentage of fat.     

Value and appropriate use of rating scales and apparative measurements in quantification of disability in Parkinson's disease

Summary Despite widespread use in pharmacotherapeutical trials, in the majority of rating scales used in Parkinson's disease (PD) validity, reliability and appropriate use have never been confirmed by statistical data. For this reason 350 unselected PD-pats. were investigated by an extensive standardized test-battery including registration of basis data, Columbia University Rating Scale (CURS), scale for assessment of functional disability (ADL), SCAG-scale, Hoehn & Jahr-scale (HY), mod. Webster step second-test (WSST), Purduepegboard, questionnaire for subjective complaints (SC), WDG, LPS1/2, 3/4, 6, 7, 10, clinical assessment of dementia, v. Zerssen-scale and orthostatic hypotension (60° tilt up). For CURS, SCAG and ADL instrumental reliability was calculated by Cronbach's alpha. For CURS, SCAG, ADL and the total data of complete test battery (CTB) principal component analysis (PCA) was performed for data reduction. CURS, SCAG and ADL showed high internal consistency (alpha 0.9). For CURS 5 factors accounting for 66% total variance could be extracted by PCA. They represent gait, rigidity, tremor, right/left dexterity (eigenvalues >1). For SCAG 3 factors (61% of total variance) representing dementia, depression and change of personality were extracted. For ADL 3 factors (67% of total variance) could be extracted, representing overall functional disability, handwriting and disablity by pain. PCA of the CTB identified 8 interpretable factors (66% of total variance) characterizing at least partially the clinical profile of PD: 1. motor disability (assessment by rating-scales) 2. dementia, 3. motor-disability (assessment by apparative measurements), 4. depression, 5. orthostatic hypotension, 6. WDG, 7. tremor and 8. pain. Our data confirm the suitability of the investigated scales and give a rational base for their appropriate use in a sense of data reduction and economical evaluation.     

Alpha-dihydroergocryptine in Parkinson's disease: a multiceuntre randomized double blind parallel group study

Introduction - A multicentre randomized double-blind parallel group study was carried out on 68 patients suffering from idiopathic Parkinson's disease (PD) treated with l -dopa for at least 1 year with inadequate therapeutic responsiveness. The aim of the study was to compare the efficacy of α-dihydroergocryptine (α-DHEC) vs lisuride as an adjunct therapy to l -dopa on dyskinesias and clinical fluctuations (Unified Parkinson's Disease Rating Scale [UPDRS] part IV), on the symptoms pattern (Columbia University Rating Scale [CURS]), on disability (Northwestern University Disability Scale [NUDS]), and to evaluate the incidence of adverse events. Patients and methods - Thirty-two patients (18 males, 14 females with a mean age of 64.5 ± 1.5 SEM) were randomized to α-dihydroergocryptine and 36 (16 males, 20 females with a mean age of 61.8 ± 1.4) to lisuride. The treatment lasted 3 months and the dosage was increased until it reached 60 mg/day of α-dihydroergocryptine and 1.2 mg/day of lisuride, while the l -dopa dosage was kept constant in both groups. Per protocol and intention to treat analyses were performed on response variables. Results - The adjunctive treatment with the two dopamine agonists determined a significant improvement of PD symptoms in both groups. Alpha-dihydroergocryptine showed a superior efficacy in reducing the clinical complications ( P <0.01 by ANOVA). The number of patients complaining of adverse events was 8 out of 32 (25%) for α-dihydroergocryptine and 24/36 (67%) for lisuride ( P <0.05). Conclusion - Alpha-dihydroergocryptine effect seems to be superior to that of lisuride both in terms of reduction of l -dopa therapy long term motor complications (UPDRS part IV) as well as in terms of the incidence and severity of adverse events.     

Contributions of dopaminergic drugs and disease severity to daytime sleepiness in Parkinson disease

BACKGROUND: Excessive daytime somnolence is a common report among patients who have Parkinson disease (PD). The relative contributions of disease severity and of the various dopaminergic drugs are unclear. OBJECTIVE: To separate and quantify the contributions of disease markers and drug doses. METHODS: Patients seen during a 7-month period at a center for movement disorders completed the Epworth Sleepiness Scale. Treatment subgroups were compared. The relationship to sedation of age; dopaminergic drug classes and doses; Hoehn and Yahr stage; duration of disease; total score on the motor subsection of the Unified Parkinson Disease Rating Scale; and the presence or absence of dementia, depression, or hallucinations was calculated using simple and multiple regression and t tests. RESULTS: The Epworth Sleepiness Scale scores were higher among patients with PD (mean [SD], 10.8 [5.3]; n = 368) compared with patients with other neurological disorders (mean, 8.5 [5.1]; n = 243; P<.001). A model containing the Hoehn and Yahr stage, levodopa dose, and use of a dopamine agonist was the best at predicting the total score of Epworth Sleepiness Scale in patients who have PD, but accounted for only 9% of the interindividual variance. The parameter estimates (SE) corresponded to a 1.02 (0.03)-point increase per Hoehn and Yahr stage, a 0.14 (0.06)-point increase per 100-mg increase in levodopa dose over 24 hours, and a 2.33 (0.57)-point increase with use of an agonist. There was no statistically significant dose response for agonists. No statistically significant difference in sedation among the commonly used dopamine agonists was found. CONCLUSIONS: Somnolence in patients with PD, which is on average 25% higher than in other neurological diseases, is related to PD stage, levodopa dose, and the use of a dopamine agonist. However, most of the variability in sedation levels in patients with PD as well as in controls is the result of, as yet, unidentified factors.     

Global versus factor-related impression of severity in Parkinson's disease: a new clinimetric index (CISI-PD).

In Parkinson's disease (PD), the Clinical Global Impression of Severity (CGIS) is often used as an additional outcome in clinical trials. It is hypothesized that this measure summarizes clinical assessment and is mainly influenced by the rating of four domains, namely, motor signs, disability, motor complications, and cognitive impairment. Ratings of these four factors were combined to form a new Clinical Impression of Severity Index for Parkinson's Disease (CISI-PD). A sample of 150 PD patients was evaluated using the following scales: Hoehn and Yahr staging, Schwab and England scale, Unified Parkinson's Disease Rating Scale, Scales for Outcomes in Parkinson's Disease-Motor Scale, CGIS, and CISI-PD. The results show that the CGIS is closely related to the above-mentioned measures (r=0.49-0.89). CISI-PD correlation with these scales was very similar (r=0.55-0.91), to the extent that the difference between corresponding coefficients was systematically less than 0.10. A multiple regression model showed that 92% of the CIGS variance was explained by the four CISI-PD items. Finally, the CISI-PD displayed adequate psychometric properties, with satisfactory internal consistency (alpha=0.90) and convergent (r>0.75) and known-groups validity. The CISI-PD is a valid and reliable measure that expands the information obtained via the CGIS.