Correlations between retinal nerve fiber layer thickness and cognitive progression in Parkinson's disease: A longitudinal study

BackgroundRetinal abnormalities measured by optical coherence tomography (OCT) have been detected in both Parkinson's disease (PD) and Alzheimer's disease (AD). Cognitive impairment is not only found in AD, but 75–90% of PD patients will also develop dementia in the late stage of disease. We assessed whether baseline retinal nerve fiber layer (RNFL) thickness predicted worsening of cognitive status over time and the correlation between RNFL thickness and the detailed impaired cognitive domains in PD.MethodsRNFL thickness was measured using high-definition OCT in 78 non-dementia PD patients. Clinical and cognitive assessments were performed at baseline and at 3.61 ± 0.65 years follow-up. Linear mixed-effects models were used to examine associations between RNFL thickness and the changes in cognitive test scores, after adjusting for age, sex, disease duration and education.ResultsAnalysis of outcomes according to baseline RNFL tertiles showed worse performance in global cognitive tests, delayed memory, and executive functions in patients with a thin RNFL. During follow-up, greater cognitive deterioration was found in thin RNFL tertile patients. Lower baseline average RNFL thickness was associated with greater annualized decline in Mini-Mental State Examination and Montreal Cognitive Assessment.ConclusionThe correlation between RNFL thickness and cognitive dysfunction suggests that OCT may be useful for predicting cognitive dysfunction in PD patients.     

Cognitive functions in Parkinson's disease: Relation to disease severity and hallucination

ObjectiveWe wished to relate severity of Parkinson's disease (PD) with cognitive function in relation to cerebral blood flow (CBF).MethodsEighty-one consecutive PD patients were enrolled in this study. We used Mini-Mental State Examination (MMSE) and Wechsler Adult Intelligence Scale-Third edition (WAIS-III) to evaluate cognitive functions, and three-dimensional stereotactic ROI template (3DSRT) and Statistical Parametric Mapping (SPM) 8 to evaluate single photon emission CT (SPECT) recordings of regional CBF.ResultsThe mean MMSE score of PD patients was 27.4 ± 2.4. The scores of most patients were higher than 23/30. On the other hand, the mean Full-scale IQ of PD patients was 88.4 ± 17.3 in WAIS-III, which was lower than that of normal controls. In particular, visuospatial function score of most patients was lower. There was significant correlation between cognitive scores and Hoehn & Yahr stage and hallucinatory episodes. PD Patients with stage III and IV showed significant deterioration in cognitive functions compared to stage II patients. Analysis of CBF revealed relative reductions in perfusion in the cerebral cortex relative to that in normal control. SPM 8 showed that cognitive functions in PD patients were positively correlated with rCBF in the thalamus and cingulate gyrus.ConclusionsThis is the study to demonstrate the cognitive impairments in PD patients using WAIS-III. Visuospatial dysfunction might be caused by decrease in rCBF in the parietal and occipital lobes and dorsolateral prefrontal cortex. The severity of cognitive impairments in PD patients was correlated with disease severity and hallucinatory episodes.     

Neurogenic orthostatic hypotension in early stage Parkinson's disease: New insights from the first 105 patients of the BoProPark study

ObjectivesThe prevalence of neurogenic orthostatic hypotension (NOH, due to cardiovascular autonomic failure) at early stage of Parkinson's disease (PD) is unknown. The aims of this study are to prospectively evaluate in a cohort of PD patients recruited within 3 years from motor onset (1) cardiovascular autonomic functions by means of cardiovascular reflex tests (CRTs) and the occurrence of NOH; (2) the frequency of orthostatic symptoms with a validated questionnaire.MethodsWe included the first 105 PD patients of the prospective “BoProPark” study. Each patient underwent CRTs (head up tilt test; Valsalva manoeuvre; deep breathing; cold face test and handgrip test) under continuous blood pressure monitoring according to standardized procedures and SCOPA-Aut questionnaire at baseline (T0) and after 16 months (T1). A group of 50 age- and sex-matched controls was used for comparison.ResultsAt T0 (mean age 61 ± 9 years, disease duration 19 ± 9 months) NOH was detected in 4/105 (3.8%) patients, whereas at T1 in 8/105 (7.6%). CRTs responses assessing sympathetic function were impaired at T0 in PD patients compared to controls and progressively worsened at T1. Only 1 patient at T0 and 3 at T1 with NOH reported orthostatic symptoms with low frequency, while the majority of patients reporting these symptoms did not have OH at testing.ConclusionsOur prospective study shows that NOH is not common at early PD stage. Asymptomatic mild sympathetic impairment was observed at first evaluation and progressed with disease evolution. Secondary OH may account for the higher prevalence of OH in PD reported so far.     

Is C-reactive protein level a marker of advanced motor and neuropsychiatric complications in Parkinson’s disease?

C-reactive protein (CRP) is a plasma protein involved in inflammation. While its levels have been associated with stroke, cognitive impairment and depression, the association with clinical characteristics of Parkinson’s disease (PD) is unknown. A total of 73 consecutive patients with PD (46 males, age 68.8 ± 11.5 years) were evaluated regarding motor as well as cognitive and psychiatric features of PD. Plasma CRP levels were determined and tests for associations with disease parameters were performed. The average level of CRP was 3.9 ± 4.1 μmol/L, and 45.2% of the patients (n = 33) had a level above 3.0 μmol/L. Patients in the high CRP group tended to be older (71.4 ± 9.2 vs. 66.7 ± 12.9 years; p = 0.08) and coronary artery disease (CAD) was more common (36 vs. 10%, p < 0.05) in the high CRP group, but no differences were found between the groups regarding gender, disease duration, levodopa dose, motor scores or most of the neuropsychiatric complications such as severity of depression, psychosis, dementia, cognitive decline or frontal lobe dysfunction. Reported depression (at present or in the past) was more common in the high CRP group (54.5 vs. 25%, p = 0.01). CRP levels in patients with PD are associated with a higher prevalence of CAD, but are not associated with PD duration or severity, or with neuropsychiatric complications other than reported depression.     

PDD-5S: A useful screening tool for Parkinson's disease dementia

IntroductionParkinson's disease dementia (PDD) contributes to poor quality of life and increases the mortality risk. Early detection and diagnosis of PDD are essential for clinical care.MethodsWe recruited patients with idiopathic Parkinson's disease (PD), who underwent clinical assessments and neuropsychological tests, at 12 teaching hospitals in Taiwan. Probable PDD was diagnosed according to the Movement Disorder Society Task Force clinical criteria. Using binary logistic regression, we selected significant items from an original 30-item informant questionnaire. We utilized these items, along with a simple cognitive test, to discriminate between PDD and nondemented PD (PD-ND).ResultsAmong the 265 PD patients (156 men, 109 women, mean age 71.9 ± 9.1 years), 102 and 163 patients were diagnosed with probable PDD and PD-ND, respectively. The mean education of participants was 8.8 ± 5.3 years, and the mean disease duration was 5.5 ± 5.4 years. When the patients fulfilled either of the following criteria: (1) a score ≥ 3 for the five endorsed screening questions, (2) a score of 1–2 for the five above screening questions combined with a score ≤ 10 items for category verbal fluency, the sensitivity and specificity of the PDD screening tool were 80.4% and 80.4%, respectively. The area under the receiver operating characteristic curve (AUC) was 0.804. We tested this screening tool in another 137 unrelated PD patients and the sensitivity, specificity, and AUC were 77.4%, 96.4%, and 0.869, respectively.ConclusionThe “PDD-5S” is a brief and useful screening tool for PDD.     

Diabetes mellitus is independently associated with more severe cognitive impairment in Parkinson disease

BackgroundThere is increasing interest in interactions between metabolic syndromes and neurodegeneration. Diabetes mellitus (DM) contributes to cognitive impairment in the elderly but its effect in Parkinson disease (PD) is not well studied.ObjectiveTo investigate effects of comorbid DM on cognition in PD independent from PD-specific primary neurodegenerations.MethodsCross-sectional study. Patients with PD (n = 148); age 65.6 ± 7.4 years, Hoehn and Yahr stage 2.4 ± 0.6, with (n = 15) and without (n = 133) comorbid type II DM, underwent [¹¹C]methyl-4-piperidinyl propionate (PMP) acetylcholinesterase (AChE) PET imaging to assess cortical cholinergic denervation, [¹¹C]dihydrotetrabenazine (DTBZ) PET imaging to assess nigrostriatal denervation, and neuropsychological assessments. A global cognitive Z-score was calculated based on normative data. Analysis of covariance was performed to determine cognitive differences between subjects with and without DM while controlling for nigrostriatal denervation, cortical cholinergic denervation, levodopa equivalent dose and education covariates.ResultsThere were no significant differences in age, gender, Hoehn and Yahr stage or duration of disease between diabetic and non-diabetic PD subjects. There was a non-significant trend toward lower years of education in the diabetic PD subjects compared with non-diabetic PD subjects. PD diabetics had significantly lower mean (±SD) global cognitive Z-scores (−0.98 ± 1.01) compared to the non-diabetics (−0.36 ± 0.91; F = 7.78, P = 0.006) when controlling for covariate effects of education, striatal dopaminergic denervation, and cortical cholinergic denervation (total model F = 8.39, P < 0.0001).ConclusionDiabetes mellitus is independently associated with more severe cognitive impairment in PD likely through mechanisms other than disease-specific neurodegenerations.     

Relationship between sleep disorders and other non-motor symptoms in Parkinson's disease

BackgroundThe association between sleep disorders and other non-motor symptoms (NMS) in Parkinson's disease (PD) has been scarcely investigated.ObjectiveTo describe the prevalence of insomnia and hypersomnia in PD and analyze their relationship with other NMS.MethodsCross-sectional, multicenter study including 388 PD patients evaluated with Hoehn and Yahr, Clinical Impression of Severity Index for PD, Scales for Outcomes in Parkinson's Disease (SCOPA)-Sleep(S), SCOPA-Cognition, SCOPA-Psychiatric Complications, SCOPA-Autonomic, Hospital Anxiety and Depression Scale, and fatigue and pain visual analogue scales. Spearman correlation coefficients, Mann–Whitney test and multiple linear regression analysis were applied.ResultsMean age (54% male) was 65.9 ± 11.2 years old, with disease duration of 8.1 ± 6.0 years and median HY = 2 (range: 1–5). Mean SCOPA-S nocturnal sleep (NS) was 5.4 ± 4.0 (range: 0–15), daytime sleepiness (DS) was 3.76 ± 3.04 (range: 0–15). Most of the sample declared nocturnal or daytime sleep problems (87.4%). Weak-to-moderate correlations were found between sleep disturbances and other NMS (range: 0.14–0.37). SCOPA-S subscales showed higher scores with the presence of most other NMS such as psychiatric complications and autonomic dysfunctions (p < 0.05). Regression models showed that fatigue, depression, urinary, cardiovascular, and thermoregulatory dysfunctions were significant determinants of SCOPA-NS score (variance: 23%); cognitive impairment, urinary, cardiovascular, and pupillomotor disorders influenced SCOPA-DS score (variance: 14%).ConclusionsInsomnia and daytime sleepiness are extremely prevalent in PD. Depression, fatigue, cognitive impairment, cardiovascular, urinary and thermoregulatory dysfunctions may contribute to insomnia/hypersomnia. This is the first clinical study to relate cardiovascular and thermoregulatory dysfunctions with sleep in PD.     

Factors that predict a change in quality of life among Parkinson's disease patients participating in a patient education program

BackgroundPatient education is essential in Parkinson's disease (PD). However, it is not known which aspects of patient education are associated with an improvement in quality of life (QoL).ObjectiveTo identify factors that predicted an improvement in QoL in PD patients that participate in an education program.MethodsEduPark is a community-hospital patient education program. PD Patients that had participated in the program between September 2013 and March 2017 were retrospectively included. QoL was prospectively evaluated (using the PDQ-8 questionnaire) before and after the patient's participation. We used mixed linear models (adjusted for the initial value of the PDQ-8) to determine socio-demographic and clinical variables that predicted the change in the PDQ-8 score.ResultsA total of 181 patients were included (mean ± standard deviation age: 62.9 ± 8.2 years; disease duration: 9.1 ± 5.3 years). 76.7% of the 103 patients having undergone a cognitive evaluation did not display cognitive impairment. We did not identify any factors that predicted the program's impact on the patient's QoL. Participation in the program was associated with a significant decrease (improvement) in the PDQ-8 score (39.4 ± 17.81 before and 35.6 ± 15.9 afterwards, P < 0.001).ConclusionWe did not identify any factors that were predictive of the patient education program's impact on QoL in patients with PD. Participation in the program was associated with a significant improvement in QoL. Our results suggest that Patient Education Programs should be more widely prescribed and developed in the management of PD.     

Predictors of onset of psychosis in patients with Parkinson's disease: Who gets it early?

IntroductionPsychosis is one of the common non-motor symptoms of PD, which substantially worsens the quality of life. Hence, it is important to identify factors that are associated with early onset of psychosis in PD. In order to identify those factors, the current study aims to compare various demographic and clinical features of PD patients with early and late onset psychosis.MethodologyIn this prospective case-control study, 51 consecutive patients with PD having psychosis (PDP) were recruited. Median of the latency of onset of psychotic symptoms from the onset of motor symptoms was calculated (5.5 years) and after doing a median split, the cohort of PDP was divided into early onset PDP (EOP, n = 25) and late onset PDP (LOP, n = 26). Both the groups were compared for several demographic and clinical characteristics.ResultsCompared to those with LOP, patients with EOP had poor scores on frontal assessment battery (13.8 ± 2.0 vs 15.3 ± 1.8, p = 0.007), more frequently had Rapid Eye movement sleep Behavior Disorder (RBD) (80% vs 46.2%, p = 0.02), Postural Instability with Gait Difficulty (PIGD) phenotype (72% vs 26.9%, p = 0.002), and excessive daytime sleepiness (Epworth Sleepiness Scale: 8.04 ± 3.7 vs 3.9 ± 3.1). Patients with LOP were older (63.4 ± 7.0 years vs 56.5 ± 8.1 years, p = 0.002) and had higher Levodopa equivalent dose/day (LEDD: 819.1 ± 365.8 vs 608.5 ± 356.3, p = 0.04) compared to those with EOP.ConclusionPresence of RBD, excessive daytime sleepiness, frontal lobe dysfunction, and PIGD phenotype of PD may be associated with early onset of psychosis in PD. Higher LEDD may not trigger early occurrence of psychosis in PD.     

Cancer incidence among Parkinson's disease patients in a 10-yrs time-window around disease onset: A large-scale cohort study

ObjectiveTo compare the incidences of any cancer and specific types among patients with Parkinson's disease (PD) in a 10-yrs time window around diagnosis, to that of the general population.MethodsWe conducted a population-based, retrospective large-scale cohort study on 7125 newly diagnosed PD patients who had just initiated anti-parkinsonian medications between 1.1.2000 and 12.31.2012; all members of Maccabi Health Services (MHS), a large Israeli HMO. Cancer incidence during the same period was collected from MHS cancer-registry. Standardized-Incidence-Ratio (SIR) accounting for age, chronological-year and sex were calculated to compare cancer risks of PD patients to that of MHS population.ResultsThe PD cohort (54% males) had a mean age at initiation of anti-parkinsonian medications of 71.2 ± 10.3years. In a time-window of 6.6 ± 3.4years before and 4.0 ± 3.9years after PD was first treated, 21% of the men and 15% of the women were diagnosed with incident-cancer. We found no-difference in any cancer risk for the PD cohort compared to the reference population: SIR = 0.99 (95%CI: 0.92–1.06) for males and 0.98 (95%CI: 0.89–1.07) for females. Risks for lung and colon cancers in the PD cohort were significantly lower for both sexes compared to the reference population. Risks for breast, central nervous system, kidney, leukemia, lymphoma, melanoma, ovarian, pancreatic, prostatic, rectal and thyroid were similar for the two populations. The SIRs did not differ between the sexes.ConclusionsWe found no difference in the risk of any-type of cancer among PD patients compared to the general population, focusing on 10yrs time-window around the initiation of anti-parkinsonian medications.     

Relationship between visual hallucinations and REM sleep behavior disorder in patients with Parkinson's disease

OBJECTIVES: REM sleep behavior disorder (RBD) has been documented to precede or to co-occur with Parkinson's disease (PD). Parkinson's disease is one of the most common neurological conditions associated with visual hallucinations. Cognitive dysfunction is present in PD, even at the early stages of these diseases. In this study we aimed to investigate the relationship between visual hallucinations and RBD in patients with idiopathic Parkinson's disease (IPD). Additionally, we evaluated the association of the cognition and the pattern of cognitive impairment with VHs and RBD, effects of factors like duration and severity of the disease and duration of levodopa usage. PATIENTS AND METHODS: Seventy-nine patients, diagnosed as PD, were included the study and then, patients were divided into four groups; with RBD and VHs (group 1), with RBD but no VHs (group 2), with VHs but no RBD (group 3), without RBD and VHs (group 4). We compared each group with the others according to demographic characteristics and neuropsychological test scores. RESULTS: Of all patients, in 46% (n=36) RBD and in 48% (n=38) VHs were observed. Our study established VHs in 58% of patients with RBD, and RBD in 55% of patients with VHs. However, due to a 40% incidence of VHs in patients without RBD, RBD and VHs were not found to be correlated. All of the neuropsychometric test scores did not reveal significant difference between groups. CONCLUSION: Although it seems like there is a small association between RBD and VHs in our patients, it was not significant. Group 1 presented with significantly worse scores in UPDRS total scores and I, II subscores.     

Dietary habits in Parkinson's disease: Adherence to Mediterranean diet

IntroductionOur objective is to describe the dietary habits, food preferences and adherence to Mediterranean diet (MeDi) of a large sample of Italian Parkinson's Disease (PD) patients compared to a group of controls.MethodsDietary habits of 600 PD patients from throughout Italy and 600 controls matched by gender, age, education, physical activity level and geographical residence, were collected using the ON-GP Food Frequency Questionnaire. Then, we compared patients by disease duration and the presence of swallowing disturbances.ResultsOverall, adherence of PD patients (males, 53.8%; mean disease duration, 9.2 ± 7.0 years) to MeDi was similar to controls (score, 4.8 ± 1.7 vs. 4.9 ± 1.6; P = 0.294). Patients consumed less alcohol and fish and drank significantly less water, coffee, and milk which resulted also in lower total fluids intake. On the contrary, they ate more fruit, cooked vegetables, cereals and baked items, more dressings and more sweets in general. Disease duration was associated with increased intake of several food groups but it was not associated with changes in MeDi score (P = 0.721). Patients with swallowing disturbances (n = 72) preferred softer and more viscous food but preferences did not result in differences in dietary pattern. However, patients with dysphagia drank less fluids (P = 0.043).DiscussionPD patients presented different dietary habits and food preferences compared to the general population and adherence to MeDi was not associated with disease duration. Self-reported dysphagia was associated with reduced intake of fluids. These aspects may be amenable to change in order to improve the management of nutritional issues in this patient population.     

Subthalamic and red nucleus volumes in patients with Parkinson’s disease: Do they change with disease progression?

ObjectiveTo examine a possible correlation between disease progression and the volumes of the subthalamic nucleus (STN) and red nucleus (RN) in patients with Parkinson disease (PD).MethodsTwelve patients with PD (mean time since diagnosis 10.8 ± 2.9 years) and age-matched 12 normal control subjects were enrolled. The volumes of the STN and RN were measured using 3-dimensional volume reconstructions of stereotactic magnetic resonance images.ResultsThe PD and control groups were similar with regard to age and gender. The STN volume was 0.13 ± 0.01 cm³ (mean ± SD) in PD patients and 0.27 ± 0.01 cm³ in controls (P < .001). The RN volume was 0.31 ± 0.02 cm³ in PD patients and 0.21 ± 0.02 cm³ in controls (P = .002). Positive correlations of RN volume with time since diagnosis (P = .004) and disease stage (P = .01) were observed. On average, the STN volumes were 48% smaller and RN volumes 32% larger in PD patients than in control subjects; the volumes of the two nuclei were negatively correlated (r = −0.46; P = .03).ConclusionsOur results suggest that advanced disease stage and longer disease duration are associated with increased RN volume. STN volume was significantly smaller in Parkinson group. These findings may be useful in estimating disease status and rate of progression, and may also have implications for surgical treatment. Larger studies are needed to validate these results and determine their usefulness.     

Side of onset does not influence cognition in newly diagnosed untreated Parkinson's disease patients

BackgroundA relation between the side of motor onset and cognitive impairment in early PD has been reported, suggesting that the asymmetric degeneration affecting subcortical regions may play a pivotal role in lateralized cognitive function. However, evidences are controversial and all previous studies were performed on treated patients, though it is known that dopaminergic therapy can affect cognition in PD.MethodsSixty-nine early untreated PD patients underwent an extensive neuropsychological battery exploring memory, visuospatial and attention/executive functions. Patients were divided with respect of the side of onset (right vs. left) and further grouped according to motor phenotype (tremor vs. rigidity-bradykinesia). Multivariate analysis of variance has been carried out to compare clinical and neuropsychological data between subgroups.ResultsThere were no differences in any neuropsychological task between right-sided and left-sided onset subgroups, irrespective of tremor dominant or rigid-bradykinetic phenotype. Age at onset was significantly higher in patients with any cognitive impairment as compared with patients without (66.7 ± 3.2 vs. 56.3 ± 6.8 years, p = 0.001).ConclusionSide of motor onset is not a major determinant for developing lateralized cognitive deficits in newly diagnosed untreated PD patients.     

Magnetic Resonance Parkinsonism Index for evaluating disease progression rate in progressive supranuclear palsy: A longitudinal 2-year study

IntroductionWe investigated the disease progression rate in patients with progressive supranuclear palsy-Richardson syndrome (PSP-RS) and PSP-parkinsonism (PSP-P) in comparison with Parkinson disease (PD) patients, using MRPI (Magnetic Resonance Parkinsonism Index), and MRPI 2.0.MethodsFifteen PSP-RS patients (disease duration, y, mean ± SD: 2.5 ± 1.1), 16 PSP-P patients (disease duration, y, mean ± SD: 6.5 ± 3.2) and 19 PD patients (disease duration, y, mean ± SD: 3.2 ± 2.3) were enrolled. All patients underwent clinical assessment and MRI at baseline, 1-year, and 2-year follow-up. MRPI, MRPI 2.0 and clinical scores over 1 and 2-years were used to evaluate disease progression rate, and to calculate sample sizes required to power placebo-controlled trials.ResultsAll groups showed increased clinical motor scores over time whereas only PSP groups had increased MRPI and MRPI 2.0 values over T1 and T2 intervals. The percentage increase over 1 and 2-years of MRPI and MRPI 2.0 values was significantly higher in PSP groups than in PD group, and in PSP-RS than in PSP-P patients while no difference between patient groups was observed when clinical motor scores were considered. Sample size estimates showed that MRPI 2.0 performed better than MRPI and clinical scales. Treatment trials with MRPI 2.0 could be performed over 2-years both in PSP-RS and PSP-P with a sample size per treatment arm of 89 and 170 patients, respectively.ConclusionsOur results demonstrate that MRPI 2.0 was more powerful than MRPI and clinical motor scales in evaluating PSP progression, and in providing the best sample size estimates for clinical trials.     

Treating sleep apnea in Parkinson's disease with C-PAP: feasibility concerns and effects on cognition and alertness

BackgroundObstructive sleep apnea (OSA) is highly prevalent in Parkinson disease (PD) and is known to contribute to cognitive impairment and daytime sleepiness. We investigated feasibility of continuous positive airway pressure treatment (CPAP) and its effects on subjective daytime sleepiness and cognitive profile in PD plus OSA subjects in a longitudinal three months follow up study.MethodsSeventy (age 71.7 ± 7.6, disease duration 9.9 ± 12.3, UPDRS-III 33.7 ± 12.5, MMSE 25.3 ± 3.6; years of education 7.7 ± 3.2) out of 228 consecutive PD patients undergoing in-lab video-polysomnography were found to have obstructive sleep apnea. Thirty-six subjects accepted to titrate therapeutic CPAP. Video-polysomnography, neuropsychological battery evaluating different cognitive domains and subjective scales for daytime sleepiness were scheduled at baseline and after three months. All the patients were given educational informations relative to diagnosis of OSA and benefits of OSA treatment, and an individualized training with CPAP.ResultsTwenty-seven (75%) subjects dropped out of the study due to CPAP intolerance. No demographic or disease-related variables (in particular, severity of OSA), could be found between subjects who completed the study versus those who dropped out. Nine subjects completed the three-month follow up, and there were no significant changes in subjective sleepiness, neuropsychological scores and sleep structure (except for reduction in apnea/hypopnea index and a trend toward increase in stage N3 sleep).ConclusionOur data show that feasibility of CPAP treatment can be significantly threatened by overall attrition rates. Further studies should consider well-structured adherence promoting interventions. The actual role of OSA as a determinant of the profile of subjective daytime sleepiness and cognition in PD, and the effects of CPAP in PD need to be further studied.     

Increased suicide risk and clinical correlates of suicide among patients with Parkinson's disease

IntroductionParkinson's disease (PD) is a debilitating, neurodegenerative condition frequently complicated by psychiatric symptoms. Patients with PD may be at higher risk for suicide than the general population, but previous estimates are limited and conflicting. The aim of this study is to estimate the suicide rate based on the clinical case registry and to identify risk factors for suicide among patients diagnosed with PD.MethodsThe target sample consisted of 4362 patients diagnosed with PD who were evaluated at a general hospital in Seoul, South Korea, from 1996 to 2012. The standardized mortality ratio for suicide among PD patients was estimated. In order to identify the clinical correlates of suicide, case-control study was conducted based on retrospective chart review. The 29 suicide cases (age: 62.3 ± 13.7 years; females: 34.5%) were matched with 116 non-suicide controls (age: 63.5 ± 9.2 years; females 56.9%) by the year of initial PD evaluation.ResultsThe SMR for suicide in PD patients was 1.99 (95% CI 1.33–2.85). Mean duration from time of initial diagnosis to suicide among cases was 6.1 ± 3.5 years. Case-control analysis revealed that male, initial extremity of motor symptom onset, history of depressive disorder, delusion, any psychiatric disorder, and higher L-dopa dosage were significantly associated with suicide among PD patients. Other PD-related variables such as UPDRS motor score were not significantly associated with death by suicide.ConclusionSuicide risk in PD patients is approximately 2 times higher than that in the general population. Psychiatric disorders, and also L-dopa medication need further attention with respect to suicide.     

Motor dual-tasking deficits predict falls in Parkinson's disease: A prospective study

IntroductionFalls severely affect lives of Parkinson's disease (PD) patients. Cognitive impairment including dual-tasking deficits contribute to fall risk in PD. However, types of dual-tasking deficits preceding falls in PD are still unclear.MethodsWalking velocities during box-checking and subtracting serial 7s were assessed twice a year in 40 PD patients over 2.8 ± 1.0 years. Fourteen patients reported a fall within this period (4 excluded fallers already reported falls at baseline). Their dual-task costs (DTC; mean ± standard deviation) 4.2 ± 2.2 months before the first fall were compared with 22 patients never reporting falls. ROC analyses and logistic regressions accounting for DTC, UPDRS-III and disease duration were used for faller classification and prediction.ResultsOnly walking/box-checking predicted fallers. Fallers showed higher DTC for walking while box-checking, p = 0.029, but not for box-checking while walking, p = 0.178 (combined motor DTC, p = 0.022), than non-fallers. Combined motor DTC classified fallers and non-fallers (area under curve: 0.75; 95% confidence interval, CI: 0.60–0.91) with 71.4% sensitivity (95%CI: 41.9%–91.6%) and 77.3% specificity (54.6%–92.2%), and significantly predicted future fallers (p = 0.023). Here, 20.4%-points higher combined motor DTC (i.e. the mean difference between fallers and non-fallers) was associated with a 2.6 (1.1–6.0) times higher odds to be a future faller.ConclusionMotor dual-tasking is a potentially valuable predictor of falls in PD, suggesting that avoiding dual task situations as well as specific motor dual-task training might help to prevent falls in PD. These findings and their therapeutic relevance need to be further validated in PD patients without fall history, in early PD stages, and with various motor-motor dual-task challenges.     

Small intestinal bacterial overgrowth in Parkinson's disease

BackgroundRecent studies reported a high prevalence of small intestinal bacterial overgrowth (SIBO) in Parkinson's disease (PD), and a possible association with gastrointestinal symptoms and worse motor function. We aimed to study the prevalence and the potential impact of SIBO on gastrointestinal symptoms, motor function, and quality of life in a large cohort of PD patients.Methods103 Consecutive PD patients were assessed using the lactulose-hydrogen breath test; questionnaires of gastrointestinal symptoms and quality of life (PDQ-39); the Unified PD Rating Scale (UPDRS) including “on”-medication Part III (motor severity) score; and objective and quantitative measures of bradykinesia (Purdue Pegboard and timed test of gait). Patients and evaluating investigators were blind to SIBO status.Results25.3% of PD patients were SIBO-positive. SIBO-positive patients had a shorter mean duration of PD (5.2 ± 4.1 vs. 8.1 ± 5.5 years, P = 0.007). After adjusting for disease duration, SIBO was significantly associated with lower constipation and tenesmus severity scores, but worse scores across a range of “on”-medication motor assessments (accounting for 4.2–9.0% of the variance in motor scores). There was no association between SIBO and motor fluctuations or PDQ-39 Summary Index scores.ConclusionsThis is the largest study to date on SIBO in PD. SIBO was detected in one quarter of patients, including patients recently diagnosed with the disease. SIBO was not associated with worse gastrointestinal symptoms, but independently predicted worse motor function. Properly designed treatment trials are needed to confirm a causal link between SIBO and worse motor function in PD.     

Impaired contrast sensitivity is associated with more severe cognitive impairment in Parkinson disease

ObjectivesDopaminergic degeneration affects both nigrostriatal projection neurons and retinal amacrine cells in Parkinson disease (PD). Parkinsonian retinopathy is associated with impaired color discrimination and contrast sensitivity. Some prior studies described associations between color discrimination deficits and cognitive deficits in PD, suggesting that contrast discrimination deficits are due, at least in part, to cognitive deficits in PD. We investigated the relationship between cognitive deficits and impaired contrast sensitivity in PD.MethodsPD subjects, n = 43; 15F/28M; mean age 66.5 ± 8.2, Hoehn and Yahr stage 2.6 ± 0.6, and duration of disease of 6.2 ± 5.0 years underwent neuropsychological and Rabin contrast sensitivity testing.ResultsMean Rabin contrast sensitivity score was 1.34 ± 0.40. Bivariate analyses showed significant correlation between Rabin contrast sensitivity scores and global cognitive z-scores (R = 0.54, P = 0.0002). Cognitive domain Z-score post hoc analysis demonstrated most robust correlation between Rabin scores and executive functions (R = 0.49, P = 0.0009), followed by verbal learning (R = 0.44, P = 0.0028), visuospatial (R = 0.39, P = 0.001) and attention z-scores (R = 0.32, P = 0.036).ConclusionsImpaired contrast sensitivity in PD is robustly associated with cognitive deficits, particularly executive function deficits. These results suggest that contrast sensitivity may be a useful biomarker for cognitive changes in PD and may have implications for driving safety evaluations in PD.