Frequency and clinical correlates of retrocollis in Parkinson's disease

PurposeTo investigate the incidence of retrocollis and to determine its clinical correlates in patients with idiopathic Parkinson's disease (PD).MethodsSeventy-four patients with PD at Hoehn and Yahr stage 5 were examined for abnormal neck postures and were classified according to neck posture. Differences in age, age at PD onset, disease duration, years from PD onset to Hoehn and Yahr stage 5, cognitive state, the levodopa equivalent dose (LED) for dopaminergic drugs, and rigidity of the neck and upper and lower extremities were examined to determine the clinical correlates of abnormal neck posture. We also evaluated retrocollis in 356 patients with PD at Hoehn and Yahr stage 1, 2, 3, and 4 and 65 age matched normal controls.ResultsOf the 74 patients with PD at Hoehn and Yahr stage 5 examined, 21 (28.4%) had retrocollis, 3 (4.1%) had antecollis, and 1 (1.4%) had antecollis and torticollis. Whereas, only one patient had retrocollis in PD patients at Hoehn and Yahr stage 4 and under. Patients with antecollis were significantly younger than those with normal neck posture and retrocollis. There were no differences in age at PD onset, disease duration, sex, years from PD motor symptom onset to Hoehn and Yahr stage 5, cognitive state, or LED between patients with and without abnormal neck postures. Neck rigidity scores were significantly higher in patients with retrocollis and antecollis than in those with normal neck posture.ConclusionsRetrocollis is not rare in patients with PD at Hoehn and Yahr stage 5, and the incidence appeared to increase as axial rigidity increased.     

Impact of serum uric acid,albumin and their interaction on Parkinson’s disease

The study aimed to investigate the correlation between Parkinson’s disease (PD) and serum levels of uric acid (UA), albumin and their interaction. A cross-sectional study was conducted to evaluate the relationship of serum UA, albumin with PD. A total of 96 PD patients and 108 healthy controls were recruited at Huai’an First People’s Hospital, Nanjing Medical University. Baseline data included age, gender, body mass index (BMI), disease duration, Hoehn and Yahr scale (H&Y) stage, serum UA and albumin levels. The levels of serum UA and albumin were significantly lower in PD patients than those in controls (P = 0.001; P = 0.000). Serum albumin levels were strikingly different in H&Y group (P = 0.004). Multivariable logistic regression showed that the levels of serum UA (P = 0.001, adjusted OR 0.993, 95% CI 0.988–0.997) and albumin (P = 0.000, adjusted OR 0.513, 95% CI 0.425–0.620) were independent risk factors in PD. The receiver operating characteristic (ROC) curve analyses showed that the area under curve (AUC) for serum UA and albumin was 0.669 (95% CI 0.594–0.744) and 0.883 (95% CI 0.835–0.931), respectively. The combination of serum albumin and UA improved the AUC to 0.898 (95% CI 0.854–0.942). Serum UA and albumin levels significantly decreased in PD patients and were independent risk factors for PD. More studies are needed to confirm our findings.     

Peripheral markers for oxidative stress in Parkinson’s disease patients of Eastern India

Oxidative stress is thought to play a major role in the pathogenesis of Parkinson’s disease (PD). Neurons are highly susceptible to a defective antioxidant scavenging system, thus inducing oxidative changes in human red blood cells (RBCs), in vivo and in vitro. Previous studies on oxidative stress in RBCs in patients with PD have yielded controversial results claiming unaltered activity to reduced activity. We have thus undertaken this study to investigate the possibility of oxidative damage to the RBCs in PD by measuring the cytosolic antioxidant enzymes viz., catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (G-Px). The biochemical parameters were measured in erythrocytes of 80 PD patients and 80 normal age-matched healthy controls. The enzymes activities were correlated with age of patients, age of onset of disease, duration of disease, United Parkinson’s Disease Rating Scale (UPDRS) and Hoehn and Yahr stage. Patients with PD had higher red blood corpuscle (RBC) activity of SOD. The CAT, and G-Px activities were significantly lower in patients with PD compared to the controls. Erythrocyte SOD, CAT and G-Px were markedly lower in those PD patients who were suffering for a greater duration of the disease and in advanced cases of PD. A significant (P < 0.05) negative correlation of enzyme activities with disease duration, UPDRS score and Hoehn and Yahr stage of the disease was found. Results of our present study concludes the implication of oxidative stress as one of the risk factors, which can initiate or promote neurodegeneration in PD by playing a role in dopaminergic neuronal loss and was correlated to the severity of the disease.     

Objective sleep measures between patients with Parkinson's disease and community-based older adults

ObjectivesPrevious studies comparing objective sleep measures between patients with Parkinson's disease (PD) and control participants were limited by their small sample size. The purpose of this study was to compare objective sleep measures between large-scale cohorts of PD outpatients and community-based older adults.MethodsIn this cross-sectional study, we measured sleep parameters for 157 PD patients using an actigraph on the non-dominant wrist for six consecutive nights (95 Hoehn–Yahr stage I/II; 62 Hoehn–Yahr stage III–V). Moreover, two consecutive nights of actigraphy were performed on 1101 community-based control participants aged ≥60 years.ResultsIn multivariable analysis, sleep efficiency (SE) was significantly lower in patients with late-stage PD by 17.5% [95% confidence interval: 15.3%–19.7%] and early-stage PD by 9.4% [7.6%–11.1%] compared to the controls (67.1% and 75.3% vs. 84.6%, respectively). Similar results were observed for wake after sleep onset (WASO) and fragmentation index (FI). Total sleep time and sleep onset latency (SOL) were significantly shorter in patients with late- and early-stage PD stage compared to the controls. Among PD patients, significant association trends between advancement of individual Hoehn–Yahr stages and worsened sleep measures of SE, WASO, and FI were observed independently of age, gender, levodopa equivalent dose, and motor function parameter.ConclusionThis study demonstrated significant and quantitative differences in objective sleep quality and quantity between PD patients and control participants. Furthermore, with advancement of disease stages, objectively measured sleep quality worsened in PD patients.     

Risk factors for hip fracture among elderly patients with Parkinson's disease

Incidence of hip fracture among patients with Parkinson's disease (PD) is high, especially in elderly women. To determine effects of various factors on hip fracture risk, we prospectively studied fractures in a cohort of 115 elderly patients of both genders with PD (46 men, 69 women; mean age, 71.9 years) for 1 year. At baseline, we recorded body mass index (BMI), Hoehn and Yahr stage, and postmenopausal interval, and also measured bone mineral density (BMD) and serum concentrations of ionized calcium, intact parathyroid hormone (PTH), pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP; a bone resorption marker), and 25-hydroxyvitamin (25-OHD). During the year hip fractures occurred in 18 patients (2 male and 16 female). We compared baseline variables between patients with and without hip fracture. PD patients with decreased BMI, lower BMD, and low concentrations of serum ionized calcium, and 25-OHD (mean 4.0 ng/ml) with compensatory hyperparathyroidsim had increased risk of hip fracture. Female PD patients with long postmenopausal intervals also had increased hip fracture risk. BMI, illness duration, postmenopausal intervals, Hoehn and Yahr stage, 25-OHD, PTH, calcium, and ICTP were determinants of BMD in patients with fracture. Elderly PD patients with low BMI, low BMD, and serum 25-OHD concentrations < or =5 ng/ml with secondary hyperparathyroidism have increased risk of hip fracture, as do female PD patients with long postmenopausal intervals.     

Cardiac sympathetic denervation correlates with clinical and pathologic stages of Parkinson's disease

Attention has been drawn to cardiac sympathetic denervation in Parkinson's disease (PD) based on clinical studies using [123I] metaiodobenzylguanidine scintigraphy; however, the histologic correlates and time course of cardiac sympathetic denervation are poorly understood. To address these issues, we used tyrosine hydroxylase (TH) immunohistochemistry to detect cardiac sympathetic nerve fibers in the epicardium of 4 normal controls, 11 cases with incidental Lewy bodies (iLBs), and 14 cases of PD. Cardiac sympathetic innervation was significantly less in PD than in normal controls and cases with iLBs (P < 0.05). There was also a decrease in TH‐immunoreactive fibers in iLB cases compared to normal controls (P < 0.01). TH‐immunoreactive fibers correlated with the PD stage (r = ?0.75, P < 0.001), as well as with Hoehn & Yahr clinical stage (r = ?0.61, P < 0.001), and disease duration (r = ?0.63, P < 0.001). Immunohistochemistry for α‐synuclein showed neurites in epicardium in PD and iLB cases, but not in normal controls. The density of α‐synuclein neurites correlated with Braak PD stage (r = 0.38, P < 0.05), Hoehn & Yahr clinical stage (r = 0.44, P < 0.05), and disease duration (r = 0.42, P < 0.05). This study demonstrates that cardiac sympathetic degeneration and α‐synuclein pathology is present in presymptomatic phase of PD, and that both increase with disease duration and severity. © 2008 Movement Disorder Society.     

Risk factors for progression in Parkinson's disease

Using case-control methodology, we assessed prevalence and duration of exposure to putative risk factors for rapid progression of Parkinson's disease (PD) in patients not taking levodopa or direct dopamine agonists. We identified 31 patients termed "rapidly progressive" who were stage I or II (Hoehn and Yahr) on their first visit to our center and who progressed to stage III during the study period; we pair-matched this group with 31 "slowly progressive" patients who had the same symptom duration and the same Hoehn and Yahr stage at study entry, but whose parkinsonism did not progress to stage III during the study. Only age of PD onset was associated with different rates of PD progression; older patients at PD onset progressed more rapidly than younger patients.     

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.     

Screening for cognitive impairment in Parkinson’s disease – which marker relates to disease severity?

Summary. The frequency and pattern of cognitive deficits in Parkinson’s disease (PD) is under discussion. We assessed 157 consecutive subjects with PD (66.4 ± 8.9 years (mean ± standard deviation); average duration of disease 3.5 ± 1.3 years; average Hoehn and Yahr stage 2.4 ± 0.9) diagnosed in centers specialized for the diagnosis and treatment of PD with brief tests for memory (Memory Impairment Screen), attention (Letter Sorting Test) and semantic fluency (category animals). Impaired memory was observed in about one half of the subjects regardless of severity of disease as assessed by staging according to Hoehn and Yahr. With greater severity, free recall was impaired and subjects required the cues to recall the items. Performance in the Letter Sorting Test and the semantic fluency task declined with increasing Hoehn and Yahr stage, also. We conclude that cognitive deficits are frequent in PD. Further analyses reveal that even in selected screening tests (e.g. semantic fluency) a significant impairment with increasing disease severity (Hoehn and Yahr stage) as opposed to disease duration alone can be demonstrated.     

Altered gut microbiota in Parkinson's disease patients/healthy spouses and its association with clinical features

IntroductionIncreasing evidence shows that gut microbiota dysbiosis may play important roles in the occurrence and progression of Parkinson's disease (PD), but the findings are inconsistent. Besides, the effect of family environment on gut microbiota dysbiosis remains unclear.MethodsWe characterized the gut microbial compositions of 63 PD patients, 63 healthy spouses (HS) and 74 healthy people (HP) using 16S rRNA sequencing. Clinical phenotypes and microbial composition were analyzed comprehensively.ResultsThere were markedly different microbial compositions among PD, HS and HP samples by alpha/beta diversity. We also found differential microbial compositions among Hoehn & Yahr stage/disease duration. Eight inflammation-associated microbial genera shared a continuously increase trend with increased Hoehn & Yahr stage and disease duration, indicating characteristic bacteria associated with deterioration in PD. Additionally, seven bacterial markers were identified for accurately differentiating PD patients from the controls (area under the curve [AUC]: 0.856).ConclusionsOur study shows altered gut microbiota in PD patients. Importantly, inflammation-associated microbial genera may play roles in PD progression. Differential microbial compositions in HS and HP samples demonstrate that the gut microbiota are also affected by family environment. Disease-associated metagenomics studies should consider the family environmental factor. Our research provides an important reference and improves the understanding of gut microbiota in PD patients.     

The frequency and nature of sleep disorders in a community-based population of patients with Parkinson's disease

Sleep disturbances in Parkinson's disease (PD) are a common problem. The aim of this study was to detail the frequency and nature of sleep disorders in a representative population of PD patients. A recently identified prevalent population, consisting of 161 PD patients were used as a representative population. Twenty-seven of 122 (22%) patients were identified as having marked sleep disorders, with sleep fragmentation and nocturia being the most commonly reported problems. Sleep scores worsened with higher Hoehn and Yahr stages. Sleep disturbances are a relatively common complication of PD and worsen with increasing Hoehn and Yahr stage.     

Increased cortical excitability with longer duration of Parkinson's disease as evaluated by transcranial magnetic stimulation

Transcranial Magnetic Stimulation (TMS) was used to evaluate the cortical excitability and central motor pathways in Parkinson's disease (PD) and correlate with severity and duration of disease. 19 cases of PD and 13 controls were enrolled. The threshold intensity (TI), cortical latency (CL), central conduction time (CCT), motor evoked potential amplitude (MEP) obtained with TMS were correlated with Hoehn and Yahr and duration of disease. The threshold intensity (TI) was significantly lower in patients of PD than controls. The TI in patients with PD was 53.16-/+8.4% patients and 67.1-/+21.6% in controls (p<0.05). This strongly correlated with duration of disease, TI being lower in patients with disease duration more than 5 years. There was no difference in the other TMS parameters - CL, CCT, MEP between patients and controls. Our study revealed increased excitability in PD which was related to longer duration of disease.     

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.     

Therapeutic factors causing hallucination in Parkinson's disease patients, especially those given selegiline

Selegiline protects nigral dopaminergic neurons and is recommended for the treatment of patients in the early stage of Parkinson's disease (PD). We treated 112 PD patients and noted that those given selegiline had a high incidence of hallucination. Our objective was to determine which clinical therapeutic factors cause such hallucinations. The Kruskal-Wallis and chi-square test showed that in 94 patients, the severity of the hallucinations was significantly related to the duration of illness, Hoehn and Yahr stage, doses of levodopa and cabergoline, whether or not selegiline was used, and whether or not medication for constipation was required. In addition, patients who were treated with a low dose of levodopa (< or =300 mg/day), who had a low Hoehn and Yahr stage, and a short duration of illness (< or =8 years) together with a high dose of selegiline or cabergoline also tended to have hallucinations. MRI findings were not related to the incidence of hallucination. When selegiline is given to patients who have PD of long duration and a high Hoehn and Yahr stage, and who already are receiving levodopa and a dopamine agonist, the doses of levodopa and the dopamine agonists given, as well as the presence of constipation, may be related to the incidence of hallucination.     

123I]beta-CIT SPECT demonstrates decreased brain dopamine and serotonin transporter levels in untreated parkinsonian patients.

Striatal dopamine transporters (DATs) and serotonin transporters (SERTs) were evaluated in untreated patients with Parkinson's disease (PD) and controls using single-photon emission computed tomography (SPECT) with 2beta-carboxymethoxy-3beta-(4-iodophenyl)tropane ([123I]beta-CIT). The striatal DAT specific to non-displaceable uptake ratios of 29, and the SERT uptake measurements of 27, PD patients were compared with those of 21 and 16 controls, respectively. The results were correlated with Unified Parkinson's Disease Rating Scale (UPDRS) scores, the Hoehn & Yahr stage, age, duration of the disease, and the major PD signs. The specific DAT binding in the caudate, the putamen and the caudate/putamen ratio were measured. In all of the PD patients the striatal uptake values were bilaterally reduced, being 36.9% (P < 0.001) lower than those of the controls. In the hemiparkinsonian patients the reduction was greater on the side contralateral to the initial symptoms (33.3% vs. 27.8%) and the uptake ratios indicated a more pronounced deficit in the putamen (39.1%) than in the caudate (27.9%). The DAT uptake correlated with the UPDRS total score and activities of daily living (ADL) and motor subscores, the Hoehn & Yahr stage, and rigidity score. PD patients had significantly higher caudate to putamen ratios than the controls. In the PD patients the SERT values were lower in the thalamic and frontal regions. The SERT uptake ratio of the frontal area correlated with the UPDRS subscore I. [123I]beta-CIT SPECT provides a useful method for confirming the clinical diagnosis of PD with correlation to disease severity. Additionally, this technique allows the simultaneous measurement of SERT uptake and shows that PD patients, interestingly, seem to have decreased SERT availability in the thalamic and frontal areas.     

Respiratory chain enzyme activities in spermatozoa from untreated Parkinson's disease patients

We studied respiratory chain enzyme activities in spermatozoa homogenates from 12 untreated Parkinson's disease (PD) male patients and from 23 age matched healthy male controls. When compared with controls, PD patients showed significantly lower specific activities for complexes I+ III, II+III, and IV. However, citrate synthase corrected activities were similar in patients and controls. Values for enzyme activities in the PD group did not correlate with age at onset, duration, scores of the Unified Parkinson's Disease Rating Scales and Hoehn and Yahr staging. These results suggest that this tissue cannot be used to develop a diagnostic test for PD.     

Circadian activity rhythm in Parkinson's disease: findings from the PHASE study

ObjectiveCircadian disruptions in Parkinson's disease (PD) are characterized as amplitude reduction rather than as phase shift; however, large-scale studies evaluating circadian rhythms between PD patients and non-PD older adults have not been performed. The present study aimed to compare the circadian activity rhythm (CAR) between PD patients and non-PD older adults.MethodsIn this cross-sectional study on 157 PD outpatients and 1111 community-dwelling older adults (controls), physical activity was measured using actigraphy at 1-min intervals over 6 days in PD patients and 2 days in non-PD older adults. Data were base-10 log-transformed and regretted to the sigmoidally transformed cosine curve.ResultsThe mean amplitude (log counts/min) and acrophase were 1.85 (SD, 0.52) and 14:19 (SD, 1:15), respectively, in the controls (n = 1111); 1.42 (0.48) and 14:24 (1:20), respectively, in the early-stage (Hoehn–Yahr I and II) PD patients (n = 95); and 1.23 (0.54) and 13:41 (1:56), respectively, in the late-stage (Hoehn–Yahr III–V) PD patients (n = 62). Multivariable analysis revealed significantly lower amplitude in the early-stage and late-stage PD groups than in the controls. The acrophase significantly advanced in the late-stage PD group than in the controls. With the advancement of PD stage, amplitude and peak significantly decreased; trough increased; acrophase and active offset advanced; and robustness weakened.ConclusionsCompared with non-PD older adults, PD patients exhibited a phase advance in CAR, along with amplitude reduction. With an advanced stage of PD, a phase advance in CAR also occurred, along with amplitude reduction and weakened robustness.     

Association of daytime sleepiness with nigrostriatal dopaminergic degeneration in early Parkinson's disease

Abstract Introduction Many patients with Parkinson's disease (PD) report daytime sleepiness. Its etiology, however, is still not fully understood. The aim of this study was to examine if the amount of nigrostriatal dopaminergic degeneration is associated with subjective daytime sleepiness in patients with PD. Patients and methods We investigated 21 patients with PD clinically and by means of [¹²³I] FP-CIT-SPECT (DaTSCAN^R). Each patient filled in the Epworth sleepiness scale (ESS), the Parkinson's Disease Sleep Scale (PDSS), and the self-rating depression scale according to Zung (SDS) to assess sleepiness, sleep quality, and depressive symptoms. Results The mean specific dopamine transporter binding in the 21 PD patients (60.8 ± 10.4 years, nine females, median Hoehn and Yahr stage 2.0) was decreased. Nine patients were in Hoehn and Yahr stage 1 (58.7 ± 6.6 years, four females; ESS score 7.4 ± 4.5; PDSS score 105.1 ± 30.9), the other 12 patients were in Hoehn and Yahr stage 2 (62.4 ± 12.6 years, five females; ESS score 6.7 ± 4.7, PDSS score 97.1 ± 25.6). Age, gender, ESS, and PDSS scores were not significantly different in both groups. However, ESS scores showed an inverse correlation with mean DAT binding in the striatum (r = -0.627, p = 0.03), the caudate nucleus (r = -0.708, p = 0.01), and the putamen (r = -0.599, p = 0.04) in patients with Hoehn and Yahr stage 2. There was no correlation of the ESS score with age, disease duration, UPDRS motor score, PDSS score, or depression score. Conclusion Subjective daytime sleepiness seems to be associated with dopaminergic nigrostriatal degeneration in early PD.     

Spatial contrast sensitivity is reduced in bilateral Parkinson's disease

We studied the contrast sensitivity functions of 41 patients with idiopathic Parkinson's disease (PD) with a wide range of parkinsonian symptomatology (Hoehn and Yahr stages 1 to 4) and 22 age-matched control subjects in a parametric design. Results demonstrated reduced contrast sensitivity in PD patients but only in those patients who had progressed beyond Hoehn and Yahr stage 1. Furthermore, there were deficits in contrast sensitivity related to the severity of PD.     

Striatal dopamine transporter binding assessed by [I-123]IPT and single photon emission computed tomography in patients with early Parkinson's disease: implications for a preclinical diagnosis

BACKGROUND: Specific binding to dopamine transporters may serve as a tool to detect early loss of nigrostriatal dopaminergic neurons in patients with Parkinson's disease. OBJECTIVE: To determine striatal dopamine transporter binding using the cocaine analogue [I-123]N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chl orophenyl) tropane ([I-123]IPT) and single photon emission computed tomography. PATIENTS AND METHODS: We studied 9 control subjects (mean age, 58 years; range, 41-69 years) and 28 patients with early Parkinson's disease (Hoehn and Yahr stages I [n = 14] and II [n = 14] [symptom duration, <5 years]; mean age, 55.5 years; range, 36-71 years). Single photon emission computed tomography was performed 90 minutes after injection of 120 to 150 MBq of radioactive [I-123]IPT. RESULTS: Specific striatal [I-123] IPT binding (mean +/- SD) was significantly reduced in patients with early Parkinson's disease (ipsilateral striatum: 4.09+/-0.97; range, 2.46-6.40; contralateral striatum: 3.32+/-0.76; range, 1.80-5.13) compared with controls (left striatum: 7.28+/-0.94; range, 5.78-8.81; right striatum: 7.41+/-1.28; range, 5.58-9.44). IPT binding ratios (mean +/- SD) were significantly lower in patients with Hoehn and Yahr stage II (ipsilateral striatum: 3.47+/-0.75; contralateral striatum: 2.96+/-0.73) compared with those with Hoehn and Yahr stage I (ipsilateral striatum: 4.72+/-0.75; contralateral striatum: 3.69+/-0.61) (P<.001). The ipsilateral striatum of patients with Hoehn and Yahr stage I showed a significant mean+/-SD reduction of IPT binding (ipsilateral striatum: 4.72+/-0.75) compared with either right or left striatum of controls (P<.001). Only in 1 patient was IPT binding to the ipsilateral striatum (ratio, 6.40) higher than the lowest value observed in the striatum of a control subject (ratio, 5.58). CONCLUSIONS: Use of [I-123] IPT and single photon emission computed tomography demonstrates a reduction of dopamine transporter binding in patients with early Parkinson's disease. Significantly reduced IPT binding already observed in the ipsilateral striatum of patients with Hoehn and Yahr stage I demonstrates the potential of this method to detect preclinical disease.