Transcranial sonography for diagnosis of Parkinson's disease

<p>Abstract</p> <p>Background</p> <p>In idiopathic Parkinson's disease (IPD) transcranial sonography (TCS) represents an alternative diagnostic method to verify clinical diagnosis. Although the phenomenon of an increased echogenicity of the Substantia nigra (SN) is well known this method is still not widly used in the diagnostic workup. Until now reliability of this method is still a matter of debate, partly because data only existed from a few laboratories using the same ultrasound machine. Therefore our study was conducted to test the reliability of this method by using a different ultrasound device and examining a large population of control and IPD subjects by two examiners to calculate interobserver reliability.</p> <p>Method</p> <p>In this study echogenicity of SN was examined in 199 IPD patients and 201 control subjects. All individuals underwent a neurological assessment including Perdue pegboard test and Webster gait test. Using a Sonos 5500 ultrasound device area of SN was measured, echogenicity of raphe, red nuclei, thalamus, caudate and lenticular nuclei, width of third and lateral ventricle were documented.</p> <p>Results</p> <p>We found a highly characteristic enlargement of the SN echogenic signal in IPD. The cut-off value for the SN area was established using a ROC curve with a sensitivity of 95% corresponding to an area of SN of 0.2 cm²and was found to be equivalent to the cut-off values of other studies using different ultrasound devices.</p> <p>Conclusions</p> <p>Our study shows that TCS is a reliable and highly sensitive tool for differentiation of IPD patients from individuals without CNS disorders.</p

Subregional 6-[18F]fluoro-ʟ-m-tyrosine Uptake in the Striatum in Parkinson's Disease

<p>Abstract</p> <p>Background</p> <p>In idiopathic Parkinson's disease (PD) the clinical features are heterogeneous and include different predominant symptoms. The aim of the present study was to determine the relationship between subregional aromatic l-amino acid decarboxylase (AADC) activity in the striatum and the cardinal motor symptoms of PD using high-resolution positron emission tomography (PET) with an AADC tracer, 6-[¹⁸F]fluoro-ʟ-<it>m</it>-tyrosine (FMT).</p> <p>Methods</p> <p>We assessed 101 patients with PD and 19 healthy volunteers. PD was diagnosed based on the UK Brain Bank criteria by two experts on movement disorders. Motor symptoms were measured with the Unified Parkinson's Disease Rating Scale (UPDRS). FMT uptake in the subregions of the striatum was analyzed using semi-automated software for region-of-interest demarcation on co-registered magnetic resonance images.</p> <p>Results</p> <p>In all PD patients, FMT uptake was decreased in the posterior putamen regardless of predominant motor symptoms and disease duration. Smaller uptake values were found in the putamen contralateral to the side with more affected limbs. The severity of bradykinesia, rigidity, and axial symptoms was correlated with the decrease of FMT uptake in the putamen, particularly in the anterior part. No significant correlation was observed between tremors and FMT uptake.</p> <p>Conclusions</p> <p>Decrease of FMT uptake in the posterior putamen appears to be most sensitive in mild PD and uptake in the anterior putamen may reflect the severity of main motor symptoms, except for tremor.</p

Subthalamic nucleus deep brain stimulation in elderly patients – analysis of outcome and complications

BACKGROUND: There is an ongoing discussion about age limits for deep brain stimulation (DBS). Current indications for DBS are tremor-dominant disorders, Parkinson's disease, and dystonia. Electrode implantation for DBS with analgesia and sedation makes surgery more comfortable, especially for elderly patients. However, the value of DBS in terms of benefit-risk ratio in this patient population is still uncertain. METHODS: Bilateral electrode implantation into the subthalamic nucleus (STN) was performed in a total of 73 patients suffering from Parkinson's disease. Patients were analyzed retrospectively. For this study they were divided into two age groups: group I (age <65 years, n = 37) and group II (age ≥ 65 years, n = 36). Examinations were performed preoperatively and at 6-month follow-up intervals for 24 months postoperatively. Age, UPDRS motor score (part III) on/off, Hoehn & Yahr score, Activity of Daily Living (ADL), L-dopa medication, and complications were determined. RESULTS: Significant differences were found in overall performance determined as ADL scores (group I: 48/71 points, group II: 41/62 points [preoperatively/6-month postoperatively]) and in the rate of complications (group I: 4 transient psychosis, 4 infections in a total of 8 patients, group II: 2 deaths [unrelated to surgery], 1 intracerebral hemorrhage, 7 transient psychosis, 3 infections, 2 pneumonia in a total of 13 patients), (p < 0.05). Interestingly, changes in UPDRS scores, Hoehn & Yahr scores, and L-dopa medication were not statistically different between the two groups. CONCLUSION: DBS of the STN is clinically as effective in elderly patients as it is in younger ones. However, a more careful selection and follow-up of the elderly patients are required because elderly patients have a higher risk of surgery-related complications and a higher morbidity rate

Postsynaptic nigrostriatal dopamine receptors and their role in movement regulation

The article presents the hypothesis that nigrostriatal dopamine may regulate movement by modulation of tone and contraction in skeletal muscles through a concentration-dependent influence on the postsynaptic D1 and D2 receptors on the follow manner: nigrostriatal axons innervate both receptor types within the striatal locus somatotopically responsible for motor control in agonist/antagonist muscle pair around a given joint. D1 receptors interact with lower and D2 receptors with higher dopamine concentrations. Synaptic dopamine concentration increases immediately before movement starts. We hypothesize that increasing dopamine concentrations stimulate first the D1 receptors and reduce muscle tone in the antagonist muscle and than stimulate D2 receptors and induce contraction in the agonist muscle. The preceded muscle tone reduction in the antagonist muscle eases the efficient contraction of the agonist. Our hypothesis is applicable for an explanation of physiological movement regulation, different forms of movement pathology and therapeutic drug effects. Further, this hypothesis provides a theoretical basis for experimental investigation of dopaminergic motor control and development of new strategies for treatment of movement disorders

Results and adverse events in 50 consecutive PD patients treated by STN-DBS

Meeting Abstract: P66

STN DBS in Parkinson's disease patients above 70 years old

Meeting Abstract: P67