Transforming Parkinson's Care in Africa (TraPCAf): protocol for a multimethodology National Institute for Health and Care Research Global Health Research Group project

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder and, according to the Global Burden of Disease estimates in 2015, was the fastest growing neurological disorder globally with respect to associated prevalence, disability, and deaths. Information regarding the awareness, diagnosis, phenotypic characteristics, epidemiology, prevalence, risk factors, treatment, economic impact and lived experiences of people with PD from the African perspective is relatively sparse in contrast to the developed world, and much remains to be learned from, and about, the continent.

METHODS

Transforming Parkinson's Care in Africa (TraPCAf) is a multi-faceted, mixed-methods, multi-national research grant. The study design includes multiple sub-studies, combining observational (qualitative and quantitative) approaches for the epidemiological, clinical, risk factor and lived experience components, as appropriate, and interventional methods (clinical trial component). The aim of TraPCAf is to describe and gain a better understanding of the current situation of PD in Africa. The countries included in this National Institute for Health and Care Research (NIHR) Global Health Research Group (Egypt, Ethiopia, Ghana, Kenya, Nigeria, South Africa and Tanzania) represent diverse African geographies and genetic profiles, with differing resources, healthcare systems, health and social protection schemes, and policies. The research team is composed of experts in the field with vast experience in PD, jointly led by a UK-based and Africa-based investigator.

DISCUSSION

Despite the increasing prevalence of PD globally, robust data on the disease from Africa are lacking. Existing data point towards the poor awareness of PD and other neurological disorders on the continent and subsequent challenges with stigma, and limited access to affordable services and medication. This multi-site study will be the first of its kind in Africa. The data collected across the proposed sub-studies will provide novel and conclusive insights into the situation of PD. The selected country sites will allow for useful comparisons and make results relevant to other low- and middle-income countries. This grant is timely, as global recognition of PD and the public health challenge it poses builds. The work will contribute to broader initiatives, including the World Health Organization's Intersectoral global action plan on epilepsy and other neurological disorders.

TRIAL REGISTRATION

https://doi.org/10.1186/ISRCTN77014546 .

Gender differences in microRNA expression in levodopa-naive PD patients

Gender is an important factor influencing epidemiological and clinical features of Parkinson's disease (PD). We aimed to evaluate gender differences in the expression of a panel of miRNAs (miR-34a-5p, miR-146a, miR-155, miR-29a, miR-106a) possibly involved in the pathophysiology or progression of disease. Serum samples were obtained from 104 PD patients (58 men and 46 women) never treated with levodopa. We measured levels of miRNAs using quantitative PCR. Correlations between miRNA expression and clinical data were assessed using the Spearman's correlation test. We used STRING to evaluate co-expression relationship among target genes. MiR-34a-5p was significantly upregulated in PD male patients compared to PD female patients (fc: 1.62; p < 0.0001). No correlation was found with age, BMI, and disease severity, assessed by UPDRS III scale, in male and female patients. MiR-146a-5p was significantly upregulated in female as compared to male patients (fc: 3.44; p < 0.0001) and a significant correlation was also observed between disease duration and mir-146a-5p. No differences were found in the expression of miR-29a, miR-106a-5p and miR-155 between genders. Predicted target genes for miR-34a-5p and miR-146-5p and protein interactions in biological processes were reported. Our study supports the hypothesis that there are gender-specific differences in serum miRNAs expression in PD patients. Follow-up of this cohort is needed to understand if these differences may affect disease progression and response to treatment.

Multiparametric MR imaging of Parkinsonisms at 3 tesla: Its role in the differentiation of idiopathic Parkinson's disease versus atypical Parkinsonian disorders

OBJECTIVES

The Nigrosome-1 and putaminal hypointensity depicted on susceptibility-weighted imaging (SWI), and midbrain atrophy assessed on T1-weighted are some of the most common radiological parameters to diagnose Parkinsonism at Magnetic Resonance (MR) imaging. Our aim is to assess the feasibility of these signs in the differentiation of Idiopathic Parkinson's disease (IPD) patients versus disease (DC) and healthy controls (HC) and in the assessment of the Atypical Progressive Parkinsonisms (APPs).

METHODS

Presence or loss of the Nigrosome-1 was assessed retrospectively on multiple-echo SWI obtained on a 3 T scan by two neuroradiologists. Results were compared with the 123I-FP-CIT SPECT images. Morphologic diagnostic features suggestive of APPs such as midbrain atrophy and putaminal hypointensity were evaluated by qualitative scores. The midbrain and putaminal scores were summed (combined score) and then added to the Nigrosome-1 score (global score).

RESULTS

The study included 126 patients with IPD (n = 56), APPs patients (n = 30; 18 PSP, 3 MSA-C, 9 MSA-P), 16 DC and 24 HC. Sensitivity and specificity of the Nigrosome-1 in discriminating IPD from controls were 96,43% and 85.00%, APPs from controls were 100% and 85%, IPD from APPs were 96,43% and 0% respectively. Combined score for midbrain atrophy and putaminal hypointensity resulted in the most accurate for distinguishing APPs from IPD with a value of ≥ 2 (AUC = 0.98).

CONCLUSION

Nigrosome-1 is a valid tool to differentiate IPD-APPs from controls. The combined score of midbrain atrophy and putaminal hypointensity represents a valid diagnostic pointer in the differential diagnosis of APPs from IPD.

Drug-induced deactivation of inhibitory networks predicts pathological gambling in PD

OBJECTIVE

Some patients with Parkinson disease (PD) develop pathological gambling when treated with dopamine agonists (DAs). However, little is known about DA-induced changes in neuronal networks that may underpin this drug-induced change in behavior in vulnerable individuals. In this case-control study, we aimed to investigate DA-induced changes in brain activity that may differentiate patients with PD with DA-induced pathological gambling (gamblers) from patients with PD without such a history (controls).

METHODS

Following overnight withdrawal of antiparkinsonian medication, patients were studied with H₂(15)O PET before and after administration of DA (3 mg apomorphine) to measure changes in regional cerebral blood flow as an index of regional brain activity during a card selection game with probabilistic feedback.

RESULTS

We observed that the direction of DA-related activity change in brain areas that are implicated in impulse control and response inhibition (lateral orbitofrontal cortex, rostral cingulate zone, amygdala, external pallidum) distinguished gamblers from controls. DA significantly increased activity in these areas in controls, while gamblers showed a significant DA-induced reduction of activity.

CONCLUSIONS

We propose that in vulnerable patients with PD, DAs produce an abnormal neuronal pattern that resembles those found in nonparkinsonian pathological gambling and drug addiction. DA-induced disruption of inhibitory key functions--outcome monitoring (rostral cingulate zone), acquisition and retention of negative action-outcome associations (amygdala and lateral orbitofrontal cortex)--together with restricted access of those areas to executive control (external pallidum)--may well explain loss of impulse control and response inhibition in vulnerable patients with PD, thereby fostering the development of pathological gambling.

Cerebral activity modulation by extradural motor cortex stimulation in Parkinson's disease: a perfusion SPECT study

Extradural motor cortex stimulation (EMCS) has been proposed as alternative to deep brain stimulation (DBS) in the treatment of Parkinson's disease (PD). Its mechanisms of action are still unclear. Neuroimaging evidenced motor cortical dysfunction in PD that can be reversed by therapy. We performed left hemisphere EMCS surgery in six advanced PD patients fulfilling CAPSIT criteria for DBS with the exception of age >70 years. After 6 months, we measured regional cerebral blood flow (rCBF) at rest with SPECT and Tc-99m cysteinate dimer bicisate off-medication with stimulator off and on. Clinical assessment included Unified Parkinson's Disease Rating Scale part II and III, Abnormal Involuntary Movement Scale and mean dopaminergic medication dosage. We used statistical parametric mapping for imaging data analysis. Clinically we observed no mean changes in motor scales, although blinded evaluation revealed some benefit in individual patients. We found significant rCBF decrements in the pre-central gyrus, pre-motor cortex and caudate nucleus bilaterally, left prefrontal areas and right thalamus. Perfusion increments were found in cerebellum bilaterally. EMCS determined significant modulation of neuronal activity within the cortico-basal ganglia-thalamo-cortical motor loop in our cohort of advanced PD patients. However, these effects were paralleled by mild and variable clinical efficacy.

Clinical and imaging characterization of a patient with idiopathic progressive ataxia and palatal tremor

We describe clinical and imaging features of a patient with sporadic progressive ataxia and palatal tremor (PAPT) of unknown etiology. There was hypertrophy of bilateral inferior olivary nuclei with hyperintense T2-weighted signal and mild cerebellar atrophy at brain magnetic resonance imaging. 18F-fluoro-2-desoxy-d-glucose positron emission tomography scanning (FDG-PET) showed hypometabolism in the red nucleus, external globus pallidus and precuneus while FP-CIT-SPECT imaging revealed mild and progressive loss of striatal dopaminergic terminals. Our findings suggest that in idiopathic PAPT involvement of the dentato-rubro-olivary pathway occurs along with some dopaminergic dysfunction.

Striatal dopamine transporter binding in patients with Parkinson's disease and severe occupational hydrocarbon exposure

We used 123I-Ioflupane SPECT to study striatal dopamine transporter (DAT) binding in 36 Parkinson's disease (PD) patients with history of severe occupational exposure to hydrocarbons. Data were compared with 38 PD patients without exposure history as well as healthy controls. Both PD cohorts showed significant striatal uptake decrements compared with controls. We found significantly lower values in the whole striatum of exposed compared with non-exposed patients (0.83 +/- 0.25 vs. 1.05 +/- 0.39; P = 0.004), more pronounced in the putamen (0.61 +/- 0.24 vs. 0.85 +/- 0.42; P = 0.004). We conclude that severe occupational exposure to hydrocarbons may modify disease course and ultimately accelerate nigro-striatal denervation.

Third cranial nerve palsy? Look for a sicca syndrome

Sjogren's syndrome (SS) is a systemic autoimmune disorder, and neurological involvement may frequently occur. Here we describe a 79-year-old woman who came to our attention for a sudden right incomplete 3rd cranial nerve palsy. Following extensive investigations, a diagnosis of primary SS was reached, and the patient recovered after treatment with ev Ig and steroids. Therefore, we suggest that SS should be considered in apparently idiopathic 3rd cranial nerve palsies, since, with the appropriate treatment, they might be transient and reversible.

Brain SPECT imaging in multiple system atrophy

Clinical diagnosis of multiple system atrophy (MSA) relays on signs and symptoms that are often difficult to identify particularly at early stage. Indeed neuropathological studies have demonstrated that MSA is the first cause of misdiagnosis in a cohort of patients presenting with parkinsonian features. Dopamine transporter imaging (DAT) shows striatal decrements in both MSA and Parkinson's disease (PD) making it not sensitive for differential diagnosis. Studies of dopamine D2 receptors with IBZM may help revealing striatal degeneration but a large overlap exist particularly if PD patients with advanced disease are included. We have measured brain flow with technetium-99m ethyl cysteinate dimer (ECD-SPECT) in 36 MSA patients and compared it with 43 PD and 39 age-matched controls. Using Statistical Parametric Mapping (SPM99) we found areas of significant reduced perfusion in the striatum, brain stem and cerebellum in MSA compared to the other groups. We believe that ECD-SPECT imaging may offer significant advantages compared to other imaging techniques in the assessment of neuronal degeneration in MSA and may help the clinician in the diagnostic characterization of patients presenting with atypical parkinsonism.

Clinical and neuropsychological follow up at 12 months in patients with complicated Parkinson's disease treated with subcutaneous apomorphine infusion or deep brain stimulation of the subthalamic nucleus

BACKGROUND

The clinical condition of advanced Parkinson's disease (PD) patients is often complicated by motor fluctuations and dyskinesias which are difficult to control with available oral medications.

OBJECTIVE

To compare clinical and neuropsychological 12 month outcome following subcutaneous apomorphine infusion (APO) and chronic deep brain stimulation of the subthalamic nucleus (STN-DBS) in advanced PD patients.

METHODS

Patients with advanced PD and medically untreatable fluctuations underwent either APO (13 patients) or STN-DBS (12 patients). All patients were clinically (UPDRS-III, AIMS, 12 h on-off daily) and neuropsychologically (MMSE, Hamilton-17 depression, NPI) evaluated at baseline and at 12 months. APO was discontinued at night.

RESULTS

At 12 months APO treatment (74.78+/-24.42 mg/day) resulted in significant reduction in off time (-51%) and no change in AIMS. Levodopa equivalent medication doses were reduced from 665.98+/-215 mg/day at baseline to 470+/-229 mg/day. MMSE, NPI, and Hamilton depression scores were unchanged. At 12 months STN-DBS resulted in significant clinical improvement in terms of reduction in daily off time (-76%) and AIMS (-81%) as well as levodopa equivalent medication doses (980+/-835 to 374+/-284 mg/day). Four out of 12 patients had stopped oral medications. MMSE was unchanged (from 28.6+/-0.3 to 28.4+/-0.6). Hamilton depression was also unchanged, but NPI showed significant worsening (from 6.58+/-9.8 to 18.16+/-10.2; p<0.02). Category fluency also declined.

CONCLUSIONS

Both APO and STN-DBS resulted in significant clinical improvement in complicated PD. STN-DBS resulted in greater reduction in dopaminergic medications and provided 24 h motor benefit. However, STN-DBS, unlike APO, appears to be associated with significant worsening on NPI resulting from long term behavioral problems in some patients.