Dietary Caffeine and Brain Dopaminergic Function in Parkinson Disease.

OBJECTIVE: This study was undertaken to investigate the effects of dietary caffeine intake on striatal dopamine function and clinical symptoms in Parkinson disease in a cross-sectional and longitudinal setting. METHODS: One hundred sixty-three early Parkinson disease patients and 40 healthy controls were investigated with [123I]FP-CIT single photon emission computed tomography, and striatal dopamine transporter binding was evaluated in association with the level of daily coffee consumption and clinical measures. After a median interval of 6.1 years, 44 patients with various caffeine consumption levels underwent clinical and imaging reexamination including blood caffeine metabolite profiling. RESULTS: Unmedicated early Parkinson disease patients with high coffee consumption had 8.3 to 15.4% lower dopamine transporter binding in all studied striatal regions than low consumers, after accounting for age, sex, and motor symptom severity. Higher caffeine consumption was further associated with a progressive decline in striatal binding over time. No significant effects of caffeine on motor function were observed. Blood analyses demonstrated a positive correlation between caffeine metabolites after recent caffeine intake and dopamine transporter binding in the ipsilateral putamen. INTERPRETATION: Chronic caffeine intake prompts compensatory and cumulative dopamine transporter downregulation, consistent with caffeine's reported risk reduction in Parkinson disease. However, this decline does not manifest in symptom changes. Transiently increased dopamine transporter binding after recent caffeine intake has implications for dopaminergic imaging guidelines. ANN NEUROL 2024;96:262-275.

Localization of stuttering based on causal brain lesions.

Stuttering affects approximately 1 in 100 adults and can result in significant communication problems and social anxiety. It most often occurs as a developmental disorder but can also be caused by focal brain damage. These latter cases may lend unique insight into the brain regions causing stuttering. Here, we investigated the neuroanatomical substrate of stuttering using three independent datasets: (i) case reports from the published literature of acquired neurogenic stuttering following stroke (n = 20, 14 males/six females, 16-77 years); (ii) a clinical single study cohort with acquired neurogenic stuttering following stroke (n = 20, 13 males/seven females, 45-87 years); and (iii) adults with persistent developmental stuttering (n = 20, 14 males/six females, 18-43 years). We used the first two datasets and lesion network mapping to test whether lesions causing acquired stuttering map to a common brain network. We then used the third dataset to test whether this lesion-based network was relevant to developmental stuttering. In our literature dataset, we found that lesions causing stuttering occurred in multiple heterogeneous brain regions, but these lesion locations were all functionally connected to a common network centred around the left putamen, including the claustrum, amygdalostriatal transition area and other adjacent areas. This finding was shown to be specific for stuttering (PFWE < 0.05) and reproducible in our independent clinical cohort of patients with stroke-induced stuttering (PFWE < 0.05), resulting in a common acquired stuttering network across both stroke datasets. Within the common acquired stuttering network, we found a significant association between grey matter volume and stuttering impact for adults with persistent developmental stuttering in the left posteroventral putamen, extending into the adjacent claustrum and amygdalostriatal transition area (PFWE < 0.05). We conclude that lesions causing acquired neurogenic stuttering map to a common brain network, centred to the left putamen, claustrum and amygdalostriatal transition area. The association of this lesion-based network with symptom severity in developmental stuttering suggests a shared neuroanatomy across aetiologies.

Bodily Maps of Symptoms and Emotions in Parkinson's Disease.

BACKGROUND: Emotions are reflected in bodily sensations, and these reflections are abnormal in psychiatric conditions. However, emotion-related bodily sensations have not been studied in neurological disorders. OBJECTIVE: The aim of this study was to investigate whether Parkinson's disease (PD) is associated with altered bodily representations of emotions. METHODS: Symptoms and emotion-related sensations were investigated in 380 patients with PD and 79 control subjects, using a topographical self-report method, termed body sensation mapping. The bodily mapping data were analyzed with pixelwise generalized linear models and principal component analyses. RESULTS: Bodily maps of symptoms showed characteristic patterns of PD motor symptom distributions. Compared with control subjects, PD patients showed decreased parasternal sensation of anger, and longer PD symptom duration was associated with increased abdominal sensation of anger (PFWE < 0.05). The PD-related sensation patterns were abnormal across all basic emotions (P < 0.05). CONCLUSIONS: The results demonstrate altered bodily maps of emotions in PD, providing novel insight into the nonmotor effects of PD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dopamine transporter binding in the brain is linked to irritable bowel syndrome in Parkinson's disease.

BACKGROUND: Gastrointestinal symptoms are common in Parkinson's disease (PD), but their neurophysiological correlates are not well understood. We recently reported that functional gastrointestinal symptoms were not associated with asymmetry per se but might be associated with lower left striatal dopamine transporter (DAT) binding. The purpose of this study was to further investigate if specific gastrointestinal symptoms associate with monoamine transporter changes in specific striatal or extrastriatal areas. METHODS: Ninety PD patients, who underwent DAT ¹2 3 I-FP-CIT SPECT imaging, were assessed using the MDS-Unified Parkinson's Disease Rating Scale part III, Rome III, and Wexner constipation score. DAT binding was calculated from striatal subregions using region-to-occipital cortex ratio. Voxel-wise analysis was used to assess the relationship between gastrointestinal symptoms and striatal DAT and extrastriatal serotonin transporter (SERT) binding. RESULTS: Irritable bowel syndrome (IBS) criteria were fulfilled in 17 patients and were linked to higher ¹2 3 I-FP-CIT binding in the right posterior putamen and adjacent areas as compared to patients without IBS. No other significant associations between gastrointestinal symptoms and DAT or SERT binding were found. CONCLUSIONS: These findings suggest that PD patients with IBS may have higher DAT binding in the right hemisphere. This finding implicates alterations of brain neurotransmitter physiology in the gastrointestinal symptoms of PD patients.

Floating door sign does not differentiate Parkinson's disease from essential tremor.

Diagnostic usefulness of the floating door sign was tested in 144 PD patients, 41 essential tremor patients and 38 controls. There were no differences in the presence of floating door sign between PD and ET patients. The sign does not seem to be a reliable differential diagnostic tool.

Serotonergic and dopaminergic control of impulsivity in gambling disorder.

Gambling disorder (GD) is major public health issue. The disorder is often characterized by elevated impulsivity with evidence from analogous substance use disorders underlining prominent roles of brain monoamines in addiction susceptibility and outcome. Critically, GD allows the study of addiction mechanisms without the confounder of the effects of chronic substances. Here, we assessed the roles of striatal dopamine transporter binding and extrastriatal serotonin transporter binding in GD as a function of impulsivity using [123 I]FP-CIT SPECT imaging in 20 older adults with GD (DSM-5 criteria; mean age 64 years) and 40 non-GD age- and sex-matched controls. We focused on GD in older individuals because there are prominent age-related changes in neurotransmitter function and because there are no reported neuroimaging studies of GD in older adults. Volume-of-interest-based and voxelwise analyses were performed. GD patients scored clearly higher on impulsivity and had higher tracer binding in the ventromedial prefrontal cortex than controls (p < 0.001), likely reflecting serotonin transporter activity. The binding in the medial prefrontal cortex positively correlated with impulsivity over the whole sample (r = 0.62, p < 0.001) as well as separately in GD patients (r = 0.46, p = 0.04) and controls (r = 0.52, p < 0.001). Striatal tracer binding, reflecting dopamine transporter activity was also positively correlated with impulsivity but showed no group differences. These findings highlight the role of prefrontal serotonergic function in GD and impulsivity. They identify cerebral coordinates of a potential target for neuromodulation for both GD and high impulsivity, a core phenotypic dimensional cognitive marker in addictions.

Fecal microbiome alterations in treatment-naive de novo Parkinson's disease.

Gut microbiota alterations in Parkinson's disease (PD) have been found in several studies and are suggested to contribute to the pathogenesis of PD. However, previous results could not be adequately adjusted for a potential confounding effect of PD medication and disease duration, as almost all PD participants were already using dopaminergic medication and were included several years after diagnosis. Here, the gut microbiome composition of treatment-naive de novo PD subjects was assessed compared to healthy controls (HC) in two large independent case-control cohorts (n = 136 and 56 PD, n = 85 and 87 HC), using 16S-sequencing of fecal samples. Relevant variables such as technical batches, diet and constipation were assessed for their potential effects. Overall gut microbiome composition differed between PD and HC in both cohorts, suggesting gut microbiome alterations are already present in de novo PD subjects at the time of diagnosis, without the possible confounding effect of dopaminergic medication. Although no differentially abundant taxon could be replicated in both cohorts, multiple short chain fatty acids (SCFA) producing taxa were decreased in PD in both cohorts. In particular, several taxa belonging to the family Lachnospiraceae were decreased in abundance. Fewer taxonomic differences were found compared to previous studies, indicating smaller effect sizes in de novo PD.

Diagnostic value of micrographia in Parkinson's disease: a study with [123I]FP-CIT SPECT.

Micrographia is a common symptom of Parkinson's disease (PD), and it may precede other motor symptoms. Despite the high prevalence of micrographia in PD, its neurobiological mechanisms are not known. Given that levodopa may alleviate consistent micrographia and that nondopaminergic essential tremor (ET) is not associated with micrographia, micrographia could possibly be used as an ancillary diagnostic method that reflects nigrostriatal dopamine function. We evaluated the usefulness of micrographia as a simple one-sentence writing test in differentiating PD from ET. A total of 146 PD patients, 42 ET patients and 38 healthy controls provided writing samples and were scanned with brain [123I]FP-CIT dopamine transporter (DAT) SPECT imaging with ROI-based and voxelwise analyses. The diagnostic accuracy of micrographia was evaluated and compared to that of DAT binding. Compared to ET and healthy controls, PD patients showed micrographia (consistent, 25.6% smaller area of handwriting sample in PD compared to ET, p = 0.002, and 27.2% smaller area of handwriting compared to healthy controls, p = 0.004). PD patients showed 133% more severe progressive micrographia compared with ET patients (median b = - 0.14 in PD, b = - 0.06 in ET, p = 0.021). In early unmedicated cognitively normal patients, consistent micrographia showed 71.2% specificity and 87.5% sensitivity in PD versus ET differentiation, but micrographia had no correlation with striatal or extrastriatal [123I]FP-CIT binding in patients with PD. The one-sentence micrographia test shows moderately good accuracy in PD versus ET differentiation. The severity of micrographia has no relationship with DAT binding, suggesting nondopaminergic mechanism of micrographia in PD.ClinicalTrials.gov identifier: NCT02650843 (NMDAT study).

Gastrointestinal Symptoms and Dopamine Transporter Asymmetry in Early Parkinson's Disease.

BACKGROUND: The neurophysiological correlates of gastrointestinal symptoms (GISs) in Parkinson's disease (PD) are not well understood. It has been proposed that in patients with a gastrointestinal origin of PD dopaminergic neurodegeneration would be more symmetric. OBJECTIVES: The aim is to assess the associations between GISs and asymmetry of nigrostriatal dopaminergic neurodegeneration in PD. METHODS: Ninety PD patients were assessed using motor and GIS scales and 123 I-FP-CIT SPECT. We calculated the asymmetry index and the predominant side of motor symptoms and dopamine transporter (DAT) imaging defect and assessed their association with GISs. RESULTS: There were no significant differences in GISs between symmetric and asymmetric dopaminergic defect. Left predominant defect was related to more GIS and higher constipation scores. CONCLUSIONS: GISs were associated with left predominant reduction in putaminal DAT binding but not asymmetry per se. It remains open whether left-sided DAT deficit is related to more pronounced GI involvement or symptom perception in PD. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.

Dopamine transporter binding in symptomatic controls and healthy volunteers: Considerations for neuroimaging trials.

OBJECTIVE: To evaluate possible differences between brain dopamine transporter (DAT) binding in a group of symptomatic parkinsonism patients without dopaminergic degeneration and healthy individuals. BACKGROUND: Dopaminergic neuroimaging studies of Parkinson's disease (PD) have often used control groups formed from symptomatic patients with apparently normal striatal dopamine function. We sought to investigate whether symptomatic patients can be used to represent dopaminergically normal healthy controls. METHODS: Forty healthy elderly individuals were scanned with DAT [123I]FP-CIT SPECT and compared to 69 age- and sex-matched symptomatic patients with nondegenerative conditions (including essential tremor, drug-induced parkinsonism and vascular parkinsonism). An automated region-of-interest based analysis of the caudate nucleus and the anterior/posterior putamen was performed. Specific binding ratios (SBR = [ROI-occ]/occ) were compared between the groups. RESULTS: DAT binding in symptomatic patients was 8.6% higher in the posterior putamen than in healthy controls (p = 0.03). Binding correlated negatively with age in both groups but not with motor symptom severity, cognitive function or depression ratings. CONCLUSIONS: Putaminal DAT binding, as measured with [123I]FP-CIT SPECT, was higher in symptomatic controls than in healthy individuals. The reason for the difference is unclear but can include selection bias when DAT binding is used to aid clinical diagnosis and possible self-selection bias in healthy volunteerism. This effect should be taken into consideration when designing and interpreting neuroimaging trials investigating the dopamine system with [123I]FP-CIT SPECT.

Diagnostic accuracy of glabellar tap sign for Parkinson's disease.

Glabellar tap or reflex (GR) is an old bedside clinical test used in the diagnostics of Parkinson's disease (PD), but its diagnostic value is unclear. This study examines the diagnostic validity and reliability of GR in PD in relation to brain dopaminergic activity. GR was performed on 161 patients with PD, 47 patients with essential tremor (ET) and 40 healthy controls immediately prior to dopamine transporter (DAT) [123I]FP-CIT SPECT scanning. The binding ratios were investigated with consideration of the GR result (normal/abnormal). In addition, the consistency of the GR was investigated with 89 patients after a mean follow-up of 2.2 years. PD and ET patients had higher GR scores than healthy controls (p < 0.001), but there was no difference in GR between PD and ET patients (p = 0.09). There were no differences in the ratio of abnormal to normal GRs between the PD and ET groups (73% vs. 64% abnormal, respectively, p = 0.13) or in DAT binding between PD patients with abnormal and normal GRs (p > 0.36). Over follow-up, the GR changed from abnormal to normal in 20% of PD patients despite the presence of clinically typical disease. The sensitivity and specificity of GR for differentiating PD from ET were 78.3% and 36.2%, respectively. Although GR has been used by clinicians in the diagnostics of PD, it does not separate PD from ET. It also shows considerable inconsistency over time, and abnormal GR has no relationship with dopamine loss. Its usefulness should be tested for other clinical diagnostic purposes.

Burden of non-motor symptoms in unclear parkinsonism and tremor: A study with [123I]FP-CIT SPECT.

BACKGROUND: Non-motor symptoms (NMSs) are clearly more prevalent in Parkinson's disease (PD) patients compared to healthy individuals. However, NMSs are also common in the elderly and other neurological conditions, and thus, it is not known whether NMSs could be used to differentiate PD from parkinsonism/tremor without dopamine deficiency. METHODS: We prospectively evaluated NMSs immediately before brain dopamine transporter (DAT) [123I]FP-CIT SPECT scanning in 193 patients with unclear parkinsonism/tremor. According to the clinical follow-up and imaging results, 84 patients had PD. NMSs and their correlations with striatal DAT binding were investigated in PD patients and in parkinsonism/tremor patients with normal dopamine function. RESULTS: Total NMS burden, anxiety or depression did not differ between PD patients and patients with normal DAT binding. DAT-normal patients reported more perception-related (p = 0.045) and attention/memory-related NMSs than PD patients (p < 0.001). Total NMS score did not correlate with striatal DAT binding in either group. CONCLUSIONS: In clinically uncertain cases, the total NMS burden cannot be used as a tool in distinguishing PD patients from patients with non-dopaminergic parkinsonism/tremor. Clinical screening of NMSs appears equally important in all patients with parkinsonism.

Exploring hyperhidrosis and related thermoregulatory symptoms as a possible clinical identifier for the dysautonomic subtype of Parkinson's disease.

OBJECTIVE: To identify associated (non-)motor profiles of Parkinson's disease (PD) patients with hyperhidrosis as a dominant problem. METHODS: This is a cross-sectional, exploratory, analysis of participants enrolled in the Non-motor Longitudinal International Study (NILS; UKCRN No: 10084) at the Parkinson's Centre at King's College Hospital (London, UK). Hyperhidrosis scores (yes/no) on question 28 of the Non-Motor Symptom Questionnaire were used to classify patients with normal sweat function (n = 172) and excessive sweating (n = 56) (Analysis 1; n = 228). NMS scale (NMSS) question 30 scores were used to stratify participants based on hyperhidrosis severity (Analysis 2; n = 352) using an arbitrary severity grading: absent score 0 (n = 267), mild 1-4 (n = 49), moderate 5-8 (n = 17), and severe 9-12 (n = 19). NMS burden, as well as PD sleep scale (PDSS) scores were then analysed along with other correlates. RESULTS: No differences were observed in baseline demographics between groups in either analysis. Patients with hyperhidrosis exhibited significantly higher total NMSS burden compared to those without (p < 0.001). Secondary analyses revealed higher dyskinesia scores, worse quality of life and PDSS scores, and higher anxiety and depression levels in hyperhidrosis patients (p < 0.001). Tertiary analyses revealed higher NMSS item scores for fatigue, sleep initiation, restless legs, urinary urgency, and unexplained pain (p < 0.001). CONCLUSIONS: Chronic hyperhidrosis appears to be associated with a dysautonomia dominant subtype in PD patients, which is also associated with sleep disorders and a higher rate of dyskinesia (fluctuation-related hyperhidrosis). These data should prompt the concept of hyperhidrosis being used as a simple clinical screening tool to identify PD patients with autonomic symptoms.

Individual parkinsonian motor signs and striatal dopamine transporter deficiency: a study with [I-123]FP-CIT SPECT.

INTRODUCTION: Total parkinsonian motor symptom severity correlates with presynaptic striatal dopamine function in patients with Parkinson's disease. There is a lack of studies that have investigated the associations between parkinsonian motor signs and striatal dopaminergic deficiency in patients with parkinsonism of an unknown origin. Identification of specific motor signs associated with the highest likelihood of striatal dopamine deficiency could aid the differential diagnostics of parkinsonian and tremor syndromes. METHODS: In this cross-sectional clinical and imaging study, detailed motor examinations were performed for 221 patients with parkinsonism or tremor of an unknown origin immediately before dopamine transporter (DAT) [I-123]FP-CIT SPECT imaging. Region-of-interest and voxel-based methods were used to investigate striatal DAT deficiency in relation to individual motor signs. RESULTS: Upper extremity rigidity and facial expression were the only motor signs that differentiated patients with normal and abnormal striatal DAT function. The presence of any upper extremity rigidity showed the highest likelihood of DAT deficiency (OR 4.79, 95% CI 1.56-14.75, P = 0.006) followed by reduced facial expression (OR 2.14, 95% CI 1.14-4.00, P = 0.018). In patients with DAT deficits, reduced facial expression was associated with DAT deficiency specifically in the caudate nucleus, and increased upper extremity rigidity was associated with DAT loss in the dorsal putamen (FWE-corrected P < 0.05). CONCLUSIONS: Increased upper extremity muscle tone and hypomimia are independently associated with a higher likelihood of striatal hypodopaminergic imaging finding. This information can be used as a factor when the clinical need of auxiliary investigations, such as DAT SPECT, is considered for patients with parkinsonism.

Predictors of normal and abnormal outcome in clinical brain dopamine transporter imaging.

Brain dopamine transporter (DAT) imaging with [(123)I]FP-CIT SPECT can be used to evaluate the integrity of the mesostriatal dopaminergic system in patients with clinically uncertain parkinsonism. To evaluate whether scanning a patient is clinically necessary, it is vital to understand possible factors that affect the scanning result. Therefore, we investigated an unselected sample of 538 consecutively scanned patients from a 6-year period, and the demographic data and indications for DAT SPECT were recorded. After scanning, the patients were divided into groups according to the scanning outcome. Multivariate binary logistic regression analyses were performed to investigate whether the pre-imaging variables had independent associations with the outcome of the scan. Three hundred and three (56.3 %) patients had abnormal scans showing a dopaminergic deficit. The independent factors associated with abnormal scans were older age (p = 0.002), asymmetry of motor symptoms (p = 0.005) and shorter symptom duration (p < 0.001). Re-evaluation of the previously established Parkinson's disease diagnosis was associated with a higher probability of an abnormal scan (74.4 % abnormal, p = 0.004), whereas the possibility of medication-induced parkinsonism was associated with a higher probability of a normal scan (35.4 %, p = 0.036). The probability of an abnormal outcome in clinical brain DAT imaging increases with known risk factors of neurodegenerative parkinsonism. However, a long duration of uncertain motor symptoms and suspicion of medication-induced parkinsonism are associated with a higher probability of a normal outcome. The findings reflect epidemiological factors in parkinsonism together with referral biases that may be used to improve the clinical use of DAT imaging.

Impulse control disorders are associated with multiple psychiatric symptoms in Parkinson's disease.

BACKGROUND: Impulse control disorders can have serious adverse consequences to the life of a patient with Parkinson's disease. Although impulse control disorders are common, a possible psychiatric comorbidity has not been fully characterized. OBJECTIVE: The aim of this study was to investigate the psychiatric symptoms exhibited by Parkinson's disease patients with impulse control disorders. METHODS: The study was conducted as a postal survey to patients in the registry of the Finnish Parkinson Association. A total of 290 Parkinson's disease patients were evaluated for impulse control disorders using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease. Psychiatric symptoms were systematically screened using the Symptom Checklist 90. RESULTS: We found that 108 of the evaluated patients had one or more impulse control disorders. Patients with impulse control disorders had markedly higher scores for symptoms of psychoticism (Bonferroni corrected p < 0.001), interpersonal sensitivity (p < 0.001), obsessive-compulsive disorder (p < 0.001), and depression (p = 0.01) when compared with patients without impulse control disorders. Impulse control disorders were shown to be independently associated with these symptoms. Patients with multiple impulse control disorders had higher scores for depression and obsessive-compulsive symptoms when compared with patients that exhibited only one impulse control disorder. COUNCLUSIONS: Our results confirm the previous observations that impulse control disorders in Parkinson's disease are linked with multiple psychiatric symptoms, including psychoticism, interpersonal sensitivity, obsessive-compulsive symptoms and depression. Clinicians treating these patients should acknowledge the concomitant psychiatric symptoms.

Physicians' views on the influence of patient participation on treatment decisions - an explorative study.

While patient participation in treatment decisions is increasingly advocated in medical literature, patient demand has been considered to cause unnecessary prescribing. Using the concept of customer participation as discussed in services marketing and management literature as a theoretical base, the paper analyses the influence of patient participation on the medical service process and treatment decision-making. A qualitative, explorative study was conducted to investigate American and British physicians' views on patient participation in the treatment of osteoporosis and schizophrenia. It became evident that in the cases of both osteoporosis and schizophrenia, patients influence prescribing decisions despite the significant difference in their willingness and ability to participate. The manifestations of patient participation were divided into three groups: (1) resources, such as the patient's condition and information about it, and his/her preconceived notions and preferences, (2) actions, such as preparing for the service, negotiating decisions and implementing the treatment, and (3) the patient's role expectations and inclination to participate. The influence of such manifestations on prescribing decision-making is discussed in detail, and differences between the studied illnesses are explained. Implications to health-care managers and practitioners are discussed.