Parkinson-ALS with a novel MAPT variant.

The mutations on microtubule associated protein tau (MAPT) gene manifest clinically with behavioural frontotemporal dementia (FTD), parkinsonism, such as progressive supranuclear palsy and corticobasal degeneration, and rarely with amyotrophic lateral sclerosis (ALS). FTD-parkinsonism and FTD-ALS are clinical overlaps included in the spectrum of MAPT mutation's phenotypes. The mutations on MAPT gene cause the dysfunction of tau protein determining its accumulation in neurofibrillary tangles. Recent data describe frequently the co-occurrence of the aggregation of tau protein and α-synuclein in patients with parkinsonism and Parkinson disease (PD), suggesting an interaction of the two proteins in determining neurodegenerative process. The sporadic description of PD-ALS clinical complex, known as Brait-Fahn-Schwarz disease, supports the hypothesis of common neuropathological pathways between different disorders. Here we report the case of a 54-year-old Italian woman with idiopathic PD later complicated by ALS carrying a novel MAPT variant (Pro494Leu). The variant is characterized by an amino acid substitution and is classified as damaging for MAPT functions. The case supports the hypothesis of tau dysfunction as the basis of multiple neurodegenerative disorders.

Automatic and controlled attentional orienting toward emotional faces in patients with Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative motor disorder that can associate with deficits in cognitive and emotional processing. In particular, PD has been reported to be mainly associated with defects in executive control and orienting attentional systems. The deficit in emotional processing mainly emerged in facial expression recognition. It is possible that the defects in emotional processing in PD may be secondary to other cognitive impairments, such as attentional deficits. This study was designed to systematically investigate the different weight of automatic and controlled attentional orienting mechanisms implied in emotional selective attention in PD. To address our purpose, we assessed drug-naïve PD patients and age-matched healthy controls with two dot-probe tasks that differed for stimuli duration. Automatic and controlled attentions were evaluated with stimuli lasting 100 ms and 500 ms, respectively. Furthermore, we introduced an emotion recognition task to investigate the performance in explicit emotion classification. The stimuli used in both the tasks dot-probe and emotion recognition were expressive faces displaying neutral, disgusted, fearful, and happy expressions.Our results showed that in PD patients, compared with healthy controls, there was 1) an alteration of automatic and controlled attentional orienting toward emotional faces in both the dot-probe tasks (with short and long durations), and 2) no difference in the emotion recognition task. These findings suggest that, from the early stages of the disease, PD can yield specific deficits in implicit emotion processing task (i.e., dot-probe task) despite a normal performance in explicit tasks that demand overt emotion recognition.

Criteria for identification of advanced Parkinson's disease: the results of the Italian subgroup of OBSERVE-PD observational study.

BACKGROUND: Frequency of Advanced Parkinson's Disease (APD) and its clinical characteristics are still not well defined. Here, we aimed to assess APD prevalence in the Italian OBSERVE-PD cohort, as well as treatment eligibility to device-aided therapies (DAT), and to compare the APD clinical judgment with the established Delphi criteria. METHODS: This sub-group analysis of the OBSERVE-PD study was performed on patients enrolled by 9 Movement Disorders centers in Italy. Motor and non-motor symptoms, PD characteristics, activities of daily living, and quality of life were assessed. Patient eligibility for DAT, response to current PD treatments, referral process, and the concordance between APD physician's judgment and Delphi criteria were also assessed. RESULTS: According to physician's judgment, 60 out of 140 patients (43%) had APD. The correlation between physician's judgment and the overall APD Delphi criteria was substantial (K = 0.743; 95%CI 0.633-0.853), mainly driven by a discrete concordance found for the presence of ≥ 2 h of daily OFF time, presence of troublesome dyskinesia, ≥ 5 times daily oral levodopa dosing, and activities of daily living limitation. Forty-four (73%) APD patients were considered eligible to DAT but only 18 of them (41%) used these therapies, while most patients, independently from their eligibility, continued to use 3-5 oral daily medications, due to fear of invasive solutions and need to have a longer time to decide. CONCLUSION: APD was frequent in the Italian OBSERVE-PD population. DAT in the eligible APD population proved to be underused, in spite of unsatisfactory symptoms control with oral medications in 67% of patients.

FDG PET in the differential diagnosis of degenerative parkinsonian disorders: usefulness of voxel-based analysis in clinical practice.

BACKGROUND: The early differential diagnosis among neurodegenerative parkinsonian disorders becomes essential to set up the correct clinical-therapeutic approach. The increased utilization of [18F] fluoro-deoxy-glucose positron emission tomography (FDG PET) and the pressure for cost-effectiveness request a systematic evaluation and a validation of its utility in clinical practice. This retrospective study aims to consider the contribution, in terms of increasing accuracy and increasing diagnostic confidence, of voxel-based FDG PET analyses in the differential diagnosis of these disorders, including Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, and cortico-basal syndrome. METHOD: Eighty-three subjects with a clinically confirmed diagnosis of degenerative parkinsonian disorders who underwent FDG brain PET/CT were selected. A voxel-based analysis was set up using statistical parametric mapping (SPM) on MATLAB to produce maps of brain hypometabolism and relative hypermetabolism. Four nuclear physicians (two expert and two not expert), blinded to the patients' symptoms, other physicians' evaluations, and final clinical diagnosis, independently evaluated all data by visual assessment and by adopting metabolic maps. RESULTS: In not-expert evaluators, the support of both hypometabolism and hypermetabolism maps results in a significant increase in diagnostic accuracy as well as clinical confidence. In expert evaluators, the increase in accuracy and in diagnostic confidence is mainly supported by hypometabolism maps alone. CONCLUSIONS: In this study, we demonstrated the additional value of combining voxel-based analyses with qualitative assessment of brain PET images. Moreover, maps of relative hypermetabolism can also make their contribution in clinical practice, particularly for less experienced evaluators.

Impulsivity Markers in Parkinsonian Subthalamic Single-Unit Activity.

BACKGROUND: Impulsive-compulsive behaviors are common in Parkinson's disease (PD) patients. However, the basal ganglia dysfunctions associated with high impulsivity have not been fully characterized. The objective of this study was to identify the features associated with impulsive-compulsive behaviors in single neurons of the subthalamic nucleus (STN). METHODS: We compared temporal and spectral features of 412 subthalamic neurons from 12 PD patients with impulsive-compulsive behaviors and 330 neurons from 12 PD patients without. Single-unit activities were extracted from exploratory microrecordings performed during deep brain stimulation (DBS) implant surgery in an OFF medication state. RESULTS: Patients with impulsive-compulsive behaviors displayed decreased firing frequency during bursts and a larger fraction of tonic neurons combined with weaker beta coherence. Information carried by these features led to the identification of patients with impulsive-compulsive behaviors with an accuracy greater than 80%. CONCLUSIONS: Impulsive-compulsive behaviors in PD patients are associated with decreased bursts in STN neurons in the OFF medication state. © 2021 International Parkinson and Movement Disorder Society.

New pharmacological and neuromodulation approaches for impulsive-compulsive behaviors in Parkinson's disease.

INTRODUCTION: A significant proportion of patients with Parkinson's disease (PD) display a set of impulsive-compulsive behaviors at some point during the course of illness. These behaviors range from the so-called behavioral addictions to dopamine dysregulation syndrome, punding and hoarding disorders. These behaviors have been consistently linked to the use of dopaminergic medications used to treat PD motor symptoms (dopamine agonists, levodopa, and other agents) and less consistently to neuromodulation techniques such as deep brain stimulation (DBS). Since there are still no approved treatments for these conditions, their pharmacological management is still a big challenge for clinicians. METHODS: We conducted an extensive review of current pharmacological and neuromodulation literature for the management of impulsive-compulsive disorders in PD patients. RESULTS: Pharmacological treatment approaches for impulsive-compulsive behaviors and DDS in PD patients include reduction of levodopa (LD), reduction/cessation of dopamine agonist (DA), and initiation of infusion therapies (apomorphine infusion and duodopa). Also, atomoxetine, a noradrenergic agent approved for the treatment of attention deficit hyperactivity disorder, showed some interesting preliminary results but there is still a lack of controlled longitudinal studies. Finally, while DBS effects on impulsive-compulsive disorders are still controversial, non-invasive techniques (such as transcranial magnetic stimulation and transcranial direct current stimulation) could have a potential positive effect but, again, there is still a lack of controlled trials. CONCLUSION: Managing impulsivity and compulsivity in PD patients is still a non-evidence-based challenge for clinicians. Controlled trials on promising approaches such as atomoxetine and non-invasive neuromodulation techniques are needed.

Raman profiling of circulating extracellular vesicles for the stratification of Parkinson's patients.

Parkinson's disease (PD) is a chronic neurodegenerative disorder, characterized by considerable clinical heterogeneity. Extracellular vesicles (EVs) were proposed as new biomarkers for PD because of their role as vehicles of multiple PD related molecules, but technical limitations exist in their detection and characterization in a clinical environment. We propose herein a Raman based protocol for the label-free analysis of circulating EVs as diagnostic and predictive tool for PD. After purification from serum of PD patients and healthy subjects, EVs were analyzed by Raman spectroscopy demonstrating the feasibility and reproducibility of the proposed biophotonic approach, its moderate accuracy in distinguishing PD patients from controls by their EV profile and the correlation between Raman data and clinical scales. Once validated, the Raman spectroscopy of circulating EVs could represent a reliable, automatable and sensitive method for the stratification of PD patients and for the evaluation of the effectiveness of rehabilitation and pharmacological treatments.

Reliability of administrative data for the identification of Parkinson's disease cohorts.

Parkinson's disease (PD) is a major worldwide public health problem with a prevalence that is expected to increase dramatically in the coming decades. Because administrative data are useful for epidemiologic and health service studies, we aimed to define procedural algorithms to identify PD patients (on a regional basis) using these data. We built two a priori algorithms, respecting privacy laws, with increasing theoretical specificity for PD including: (1) a hospital discharge diagnosis of PD; (2) PD-specific exemption; (3) a minimum of two separate prescriptions of an antiparkinsonian drug. The two algorithms differed for drugs included. Sensitivities were tested on an opportunistic sample of 319 PD patients from the databases of 5 regional movement disorders clinics. The estimated prevalence of PD in the sample population from Tuscany was 0.49 % for algorithm 1 and 0.28 % for algorithm 2. Algorithm 1 correctly identified 291 PD patients (sensitivity 91.2 %), and algorithm 2 identified 242 PD patients (sensitivity 75.9 %). We developed two reproducible algorithms demonstrating increasing theoretical specificity with good sensitivity in identifying PD patients based on an evaluation of administrative data. This may represent a low-cost strategy to reliably follow up a large number of PD patients as a whole for evaluating the effects of therapies, disease progression and prevalence.

Parkinson's Disease Case Ascertainment in the EPIC Cohort: The NeuroEPIC4PD Study.

BACKGROUND/AIMS: Large epidemiological prospective studies represent an important opportunity for investigating risk factors for rare diseases such as Parkinson's disease (PD). Here we describe the procedures we used for ascertaining PD cases in the EPIC (European Prospective Investigation into Cancer and Nutrition) study. METHODS: The following three-phase procedure was used: (1) elaboration of a NeuroEPIC4PD template for clinical data collection, (2) identification of all potential PD cases via record linkage and (3) validation of the diagnosis through clinical record revision, in a population of 220,494 subjects recruited in 7 European countries. All cases were labelled with the NeuroEPIC4PD diagnoses of 'definite', 'very likely', 'probable', or 'possible' PD. RESULTS: A total of 881 PD cases were identified, with over 2,741,780 person-years of follow-up (199 definite, 275 very likely, 146 probable, and 261 possible). Of these, 734 were incident cases. The mean age at diagnosis was 67.9 years (SD 9.2) and 458 patients (52.0%) were men. Bradykinesia was the most frequent presenting motor sign (76.5%). Tremor-dominant and akinetic rigid forms of PD were the most common types of PD. A total of 289 patients (32.8%) were dead at the time of the last follow-up. CONCLUSIONS: This exercise proved that it is feasible to ascertain PD in large population-based cohort studies and offers a potential framework to be replicated in similar studies.

Comparing the effects of augmented virtual reality treadmill training versus conventional treadmill training in patients with stage II-III Parkinson's disease: the VIRTREAD-PD randomized controlled trial protocol.

Background: Intensive treadmill training (TT) has been documented to improve gait parameters and functional independence in Parkinson's Disease (PD), but the optimal intervention protocol and the criteria for tailoring the intervention to patients' performances are lacking. TT may be integrated with augmented virtual reality (AVR), however, evidence of the effectiveness of this combined treatment is still limited. Moreover, prognostic biomarkers of rehabilitation, potentially useful to customize the treatment, are currently missing. The primary aim of this study is to compare the effects on gait performances of TT + AVR versus TT alone in II-III stage PD patients with gait disturbance. Secondary aims are to assess the effects on balance, gait parameters and other motor and non-motor symptoms, and patient's satisfaction and adherence to the treatment. As an exploratory aim, the study attempts to identify biomarkers of neuroplasticity detecting changes in Neurofilament Light Chain concentration T0-T1 and to identify prognostic biomarkers associated to blood-derived Extracellular Vesicles. Methods: Single-center, randomized controlled single-blind trial comparing TT + AVR vs. TT in II-III stage PD patients with gait disturbances. Assessment will be performed at baseline (T0), end of training (T1), 3 (T2) and 6 months (T3, phone interview) from T1. The primary outcome is difference in gait performance assessed with the Tinetti Performance-Oriented Mobility Assessment gait scale at T1. Secondary outcomes are differences in gait performance at T2, in balance and spatial-temporal gait parameters at T1 and T2, patients' satisfaction and adherence. Changes in falls, functional mobility, functional autonomy, cognition, mood, and quality of life will be also assessed at different timepoints. The G*Power software was used to estimate a sample size of 20 subjects per group (power 0.95, α < 0.05), raised to 24 per group to compensate for potential drop-outs. Both interventions will be customized and progressive, based on the participant's performance, according to a predefined protocol. Conclusion: This study will provide data on the possible superiority of AVR-associated TT over conventional TT in improving gait and other motor and non-motor symptoms in persons with PD and gait disturbances. Results of the exploratory analysis could add information in the field of biomarker research in PD rehabilitation.

Increased glucosylsphingosine levels and Gaucher disease in GBA1-associated Parkinson's disease.

INTRODUCTION: Gaucher's disease (GD) is caused by biallelic mutations in the GBA1 gene, leading to reduced glucocerebrosidase (GCase) activity and substrate (glucosylceramide and glucosylsphingosine, GlcSph) accumulation. GBA1 variant carriers are at risk of Parkinson's disease (PD), but only those with biallelic mutations cross the threshold of GCase reduction, leading to substrate accumulation and GD. The link between GBA1 mutations, GD and PD is not fully understood. Here we aimed at reporting the results of a large PD population screening with dried blood spot tests for GD. METHODS: We measured GCase activity and GlcSph levels in 1344 PD patients with dried blood spot tests, and performed GBA1 genetic sequencing. RESULTS: While the GCase activity was reduced in GBA1-PD carriers compared to wild type PD, GlcSph was increased in GBA1-PD compared to GBA1-controls, regardless of the underlying type of GBA1 variant. 13.6 % and 0.4 % of PD patients had mono- or biallelic GBA1 mutations respectively. GCase deficiency, lipid accumulation and clinical manifestations of GD was detected in five PD patients with biallelic GBA1 mutations, of whom four had a risk combined with a GD causing variant. CONCLUSIONS: GlcSph appearing higher in PD may represent a reliable biomarker of the disease and deserves to be further investigated. This study highlights the importance of screening PD patients for possible underlying GD, which is a treatable condition that should not be missed. We diagnosed GD cases carrying a "risk" variant in one allele, which is an unprecedented finding deserving further investigation.

Daytime course of sleepiness in de novo Parkinson's disease patients.

Normal subjects show an increase of sleepiness in the morning, early afternoon and before sleep. In the advanced stages of Parkinson's disease (PD) the mean level of sleepiness is quite high, while with respect to healthy subjects it seems to be unchanged in the early stages. The aim of this study was to evaluate the time-course of the sleepiness level during the wakefulness period in untreated patients with early-stage Parkinson's disease. Eighteen Parkinson's disease patients who had never been treated before with dopaminergic drugs (male = 9, female = 9, age: 68.39 ± 1.89, mean ± standard error) and 18 healthy subjects (male = 9, female = 9, age: 67.22 ± 1.98) were recruited for this study. All subjects underwent continuous actigraphic recording for three consecutive days, during which they also completed the Karolinska Sleepiness Scale (KSS) once an hour throughout wakefulness. Our results showed a higher level of sleepiness in the patients than the controls in the hours following awakening and in the early afternoon, specifically at 08:00 and 14:00 hours (08:00 hours, PD patients, KSS: 3 ± 0.3 versus healthy subjects, KSS: 2 ± 0.2, P < 0.05; 14:00 hours, PD patients, KSS: 4.4 ± 0.5 versus healthy subjects, KSS: 3 ± 0.3, P < 0.05). We suggest that some daytime hours are sensitive windows showing the first increase of sleepiness which will spread later to the whole daytime.

Validation of the Italian version of the Movement Disorder Society--Unified Parkinson's Disease Rating Scale.

The Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) has been available in English since 2008. As part of this process, the MDS-UPDRS organizing team developed guidelines for development of official non-English translations. We present here the formal process for completing officially approved non-English versions of the MDS-UPDRS and specifically focus on the first of these versions in Italian. The MDS-UPDRS was translated into Italian and tested in 377 native-Italian speaking PD patients. Confirmatory and exploratory factor analyses determined whether the factor structure for the English-language MDS-UPDRS could be confirmed in data collected using the Italian translation. To be designated an 'Official MDS translation,' the Comparative Fit Index (CFI) had to be ≥0.90 relative to the English-language version. For all four parts of the Italian MDS-UPDRS, the CFI, in comparison with the English-language data, was ≥0.94. Exploratory factor analyses revealed some differences between the two datasets, however these differences were considered to be within an acceptable range. The Italian version of the MDS-UPDRS reaches the criterion to be designated as an Official Translation and is now available for use. This protocol will serve as outline for further validation of this in multiple languages.

Psychosis associated to Parkinson's disease in the early stages: relevance of cognitive decline and depression.

OBJECTIVE: To evaluate the prevalence of psychosis associated with Parkinson's disease (PSY-PD) in its early stages, its incidence over a 24 month follow-up period and the association with motor and non-motor clinical features. METHODS: PRIAMO is a 2 year longitudinal observational study that has enrolled patients with parkinsonism in 55 Italian centres. A cohort of 495 patients with early disease stage PD (baseline Hoehn and Yahr score ≤ 2, disease's duration (median) 3.4 years) were followed for 2 years. PSY-PD was evaluated by means of a clinician rated questionnaire and defined as the presence of at least one of the following symptoms occurring for at least 1 month: illusions, hallucinations, jealousy ideas and persecutory ideas. Patients with and without PSY-PD were compared on several clinical variables, encompassing motor and non-motor features. RESULTS: The prevalence of PSY-PD at baseline was 3%; the incidences at 12 and 24 months were 5.2% and 7.7%, respectively. Longer disease duration and prescription of dopamine agonists at baseline were associated with the development of PSY-PD over the 24 month period. At this follow-up time, worse disease severity, decline in cognitive performances, presence of depressive symptoms and anxiety were more frequently observed in PSY-PD. CONCLUSIONS: Psychotic type symptoms may occur in the early stages of PD although less frequently than in later stages. Beyond dopaminergic treatment, there are disease related factors, such as disease severity and the occurrence of cognitive and depressive symptoms, which may underlie the onset of psychotic type symptoms from the earliest stages.

Frontal assessment battery scores and non-motor symptoms in parkinsonian disorders.

Using data from the PRIAMO study, we investigated non-motor symptoms (NMS) versus frontal lobe dysfunction in patients with idiopathic Parkinson disease (PD); 808 patients with PD and 118 with atypical parkinsonisms (AP) were consecutively enrolled at 55 Centers in Italy. Twelve categories of NMS were investigated. Cognitive impairment was defined as a Mini-Mental Status Evaluation score ≤ 23.8 and frontal lobe dysfunction as a Frontal Assessment Battery (FAB) score ≤ 3.48. Multivariable logistic regression was used to identify predictor of frontal lobe dysfunction in 524 PD patients, and a generalized linear model was used for each of the six FAB items. Not only the total FAB scores but also the single FAB items were lower in AP versus PD (p ≤ 0.005). Age (OR = 1.05), cognitive impairment (OR = 9.54), lack of cardiovascular symptoms (OR = 3.25), attention or memory problems (OR = 0.59) and treatment with L: -DOPA (OR = 5.58) were predictors of frontal lobe dysfunction. MMSE was negatively associated with all FAB items (ß ≤ -0.16) and age with all FAB items but prehension behavior (ß ≤ -0.01). Previous use of L: -DOPA was negatively associated with verbal fluency (ß = -0.32) possibly acting as surrogate marker of disease duration. Cognitive impairment is a predictor of frontal lobe dysfunction. Among NMS, lack of attention or memory problems were negatively associated with frontal impairment. Further studies are nonetheless needed to better identify the predictors of frontal impairment in PD patients.

Impulsivity is associated with firing regularity in parkinsonian ventral subthalamic nucleus.

Impulsive-compulsive behaviors (ICB) are over-represented in Parkinson's disease (PD) patients. Neurons in the ventral subthalamic nucleus (STN) might play a predominant role in the modulation of impulsivity. We characterized the firing regularity of 742 subthalamic neurons from 24 PD patients (12 ICB+ and 12 ICB-) in an OFF medication state. We computed the firing regularity in the dorsal and ventral STN regions, and we compared their performance in discriminating ICB patients. Regularity of ventral neurons in ICB+ patients is higher and supports a significant discrimination between the two cohorts. These results substantiate a ventral location of neurons involved in impulsivity.

Prevalence and impact of COVID-19 in Parkinson's disease: evidence from a multi-center survey in Tuscany region.

BACKGROUND: If Parkinson's Disease (PD) may represent a risk factor for Coronavirus disease 2019 (COVID-19) is debated and there are few data on the direct and indirect effects of this pandemic in PD patients. OBJECTIVE: In the current study we evaluated the prevalence, mortality and case-fatality of COVID-19 in a PD cohort, also exploring possible risk factors. We also aimed to investigate the effect of lockdown on motor/non-motor symptoms in PD patients as well as their acceptability/accessibility to telemedicine. METHOD: A case-controlled survey about COVID-19 and other clinical features in PD patients living in Tuscany was conducted. In non-COVID-19 PD patients motor/non-motor symptoms subjective worsening during the lockdown as well as feasibility of telemedicine were explored. RESULTS: Out of 740 PD patients interviewed, 7 (0.9%) were affected by COVID-19, with 0.13% mortality and 14% case-fatality. COVID-19 PD patients presented a higher presence of hypertension (p < 0.001) and diabetes (p = 0.049) compared to non-COVID-19. In non-COVID-19 PD population (n = 733) about 70% did not experience a subjective worsening of motor symptoms or mood, anxiety or insomnia. In our population 75.2% of patients was favorable to use technology to perform scheduled visits, however facilities for telemedicine were available only for 51.2% of cases. CONCLUSION: A higher prevalence of COVID-19 respect to prevalence in Tuscany and Italy was found in the PD population. Hypertension and diabetes, as for general population, were identified as risk factors for COVID-19 in PD. PD patients did not experience a subjective worsening of symptoms during lockdown period and they were also favorable to telemedicine, albeit we reported a reduced availability to perform it.

Predictive potential of pre-operative functional neuroimaging in patients treated with subthalamic stimulation.

PURPOSE: The aim of this study was to investigate the predictive potential of pre-operative regional cerebral blood flow (rCBF) in the pre-supplementary motor area (pre-SMA) and clinical factors in Parkinson's disease (PD) patients treated with subthalamic nucleus (STN) stimulation. METHODS: Ten patients underwent rCBF SPECT and motor Unified Parkinson's Disease Rating Scale (UPDRS) pre- and post-operatively during stimulation at 5 and 42 months. Statistical parametric mapping (SPM) was used to extract rCBF values in the pre-SMA because it is related with motor improvement. Post-operative outcomes included motor response to stimulation and percent improvement in UPDRS. Pre-operative predictors were explored by correlation test, linear regression and multivariate analyses. RESULTS: Higher pre-operative rCBF in the pre-SMA and younger age were associated with favourable outcomes at 5 and 42 months. Pre-operative rCBF results were significantly associated with baseline clinical factors. CONCLUSION: This study shows that PD patients with younger age have higher rCBF values in the pre-SMA and better outcome, thus giving the rationale to the hypothesis that STN stimulation could be considered early in the course of disease.

Brain metabolic correlates of dopaminergic degeneration in de novo idiopathic Parkinson's disease.

PURPOSE: The aim of the present study was to evaluate the reciprocal relationships between motor impairment, dopaminergic dysfunction, and cerebral metabolism (rCMRglc) in de novo Parkinson's disease (PD) patients. METHODS: Twenty-six de novo untreated PD patients were scanned with (123)I-FP-CIT SPECT and (18)F-FDG PET. The dopaminergic impairment was measured with putaminal (123)I-FP-CIT binding potential (BP), estimated with two different techniques: an iterative reconstruction algorithm (BP(OSEM)) and the least-squares (LS) method (BP(LS)). Statistical parametric mapping (SPM) multiple regression analyses were performed to determine the specific brain regions in which UPDRS III scores and putaminal BP values correlated with rCMRglc. RESULTS: The SPM results showed a negative correlation between UPDRS III and rCMRglc in premotor cortex, and a positive correlation between BP(OSEM) and rCMRglc in premotor and dorsolateral prefrontal cortex, not surviving at multiple comparison correction. Instead, there was a positive significant correlation between putaminal BP(LS) and rCMRglc in premotor, dorsolateral prefrontal, anterior prefrontal, and orbitofrontal cortex (p < 0.05, corrected for multiple comparison). CONCLUSIONS: Putaminal BP(LS) is an efficient parameter for exploring the correlations between PD severity and rCMRglc cortical changes. The correlation between dopaminergic degeneration and rCMRglc in several prefrontal regions likely represents the cortical functional correlate of the dysfunction in the motor basal ganglia-cortical circuit in PD. This finding suggests focusing on the metabolic course of these areas to follow PD progression and to analyze treatment effects.