The TANDEM investigation: efficacy and tolerability of levodopa-carbidopa intestinal gel in (LCIG) advanced Parkinson's disease patients.

The TANDEM investigation was carried out in 17 Italian Movement Disorder centers on behalf of a joint initiative of neurologist members of the Italian Academy for Parkinson's disease and Movement Disorders (LIMPE-DISMOV Academy) and gastroenterologist members of the Italian Society of Digestive Endoscopy (SIED) to evaluate the efficacy and tolerability of levodopa-carbidopa intestinal gel (LCIG) in patients with advanced Parkinson's disease (PD) in routine medical care. Motor scores in "ON" and OFF" state (UPDRS-III), complications of therapy (UPDRS-IV), activities of daily living, sleep disorders and quality of life were evaluated at baseline and at two follow-up assessments (FUV1 and FUV2) within the initial 12-month LCIG treatment. In 159 patients (55% males) with a mean age of 69.1 ± 6.6 years and a diagnosis of PD since 13.6 ± 5.5 years, the UPDRS-III total score (in "OFF") decreased from baseline (45.8 ± 13.2) to FUV1 (41.0 ± 17.4; p < 0.001) and FUV2 (40.5 ± 15.5; p < 0.001), the UPDRS-IV total score decreased from baseline (8.8 ± 2.9) to FUV1 (5.1 ± 3.4; p < 0.001) and FUV2 (5.5 ± 3.2; p < 0.001). The percentage of patients exhibiting freezing, dystonia, gait/walking disturbances, falls, pain and sleep disorders was significantly reduced. Twenty-eight device complications were reported and 11 (6.9%) patients prematurely terminated the study. LCIG after 12-month treatment led to sustained improvement of time spent in "OFF", complications of therapy, PD-associated symptoms and sleep disorders. LCIG tolerability was consistent with the established safety profile of LCIG.

Central conduction abnormalities in patients receiving levodopa-carbidopa intestinal gel infusion.

In recent years, several studies have reported a relatively high frequency of polyneuropathy in patients with Parkinson's disease (PD), in particular, in patients receiving levodopa-carbidopa intestinal gel (LCIG) infusion. In spite of the several patients investigated with nerve conduction studies, no study has prospectively explored a possible central nervous system involvement of patients receiving LCIG infusion. We prospectively evaluated eight PD patients receiving LCIG infusion, who underwent neurophysiological evaluations with nerve conduction studies, visual, somatosensory and motor evoked potentials before LCIG infusion, and 1 and 6 months after. At 6 months follow-up, we found significant reduction in sural nerve SNAP amplitude, increase of central sensory conduction time N22-P40, and increases of central motor conduction time recorded from I dorsal interosseous and tibialis anterior. In PD patients with LCIG infusion, we found a subclinical neurophysiological impairment of both peripheral and central nervous system.

Clinical and genetic analyses of familial and sporadic frontotemporal dementia patients in Southern Italy.

INTRODUCTION: We investigated the clinical differences between familial and sporadic frontotemporal dementia (FTD), screening for mutations in known FTD genes. METHODS: We diagnosed 22 affected individuals belonging to eight families and 43 sporadic cases with FTD in Apulia, Southern Italy, in 2 years. Mutations in common causative FTD genes (GRN, MAPT, VCP, and TARDBP) and C9ORF72 expansions were screened. RESULTS: Behavioral variant of FTD was the most common clinical subtype (50% and 69% in familial and sporadic cases, respectively). Social conduct impairment/disinhibition, loss of insight, and inflexibility were the most frequent clinical features observed at onset. One new mutation was identified in GRN in family A. DISCUSSION: Disease onset in sporadic FTD was more frequently characterized by a clustering of behavioral symptoms with apathy and loss of personal hygiene. Mutations in common causative FTD genes are not a major cause of familial and sporadic FTD in the Southern Italian population.

Motor outcomes in patients with advanced Parkinson's disease treated with levodopa/carbidopa intestinal gel in Italy: an interim analysis from the GREENFIELD observational study.

Several levodopa/carbidopa intestinal gel (LCIG) studies showed a significant reduction of OFF time and a significant increase of ON time, as well as a reduction of dyskinesia, and improvement of non-motor symptoms and quality of life. However, few studies have been conducted in a large population for more than 3 years. Interim outcomes from GREENFIELD observational study on a large Italian cohort of advanced PD patients who started LCIG in routine care between 2007 and 2014, still on treatment at the enrollment, are presented. Comparison between baseline (before LCIG start) and visit 1 (at enrollment) is reported. Primary endpoint was Unified Parkinson's Disease Rating Scale (UPDRS) IV Item 39; secondary endpoints were UPDRS I and II, as outcome of quality of life. Overall, 145 of 148 enrolled patients from 14 Movement Disorder Centers in Italy were evaluable with a mean LCIG treatment period of 1.38 ± 1.66 years at enrollment. Compared with baseline, the mean score regarding daily time spent in OFF (UPDRS IV Item 39) at visit 1 significantly decreased from 2.1 ± 0.8 to 0.9 ± 0.7 (57 % reduction vs baseline, P < 0.0001); UPDRS IV improved by 39 % (P < 0.0001); scores for dyskinesia duration and disability were reduced by 28 % (1.8 ± 1.0-1.3 ± 0.9; P < 0.0001) and 33 % (1.5 ± 1.1 to 1.0 ± 1.0; P < 0.0001), respectively; and the scores for painful dyskinesia and early morning dystonia were reduced by 56 % (0.9 ± 1.0-0.4 ± 0.7; P < 0.0001) and 25 % (0.4 ± 0.5-0.3 ± 0.5; P < 0.001), respectively. The preliminary results of this interim analysis support the efficacy of LCIG on motor complications and activities of daily living.

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.

Family History in Parkinson's Disease: A National Cross-Sectional Study.

BACKGROUND: Family history of Parkinson's disease (PD) is a common finding in PD patients. However, a few studies have systematically examined this aspect. OBJECTIVES: We investigated the family history of PD patients, comparing demographic and clinical features between familial PD (fPD) and sporadic PD (sPD). METHODS: A cross-sectional study enrolling 2035 PD patients was conducted in 28 Italian centers. Clinical data and family history up to the third degree of kinship were collected. RESULTS: Family history of PD was determined in 21.9% of patients. fPD patients had earlier age at onset than sporadic patients. No relevant differences in the prevalence of motor and nonmotor symptoms were detected. Family history of mood disorders resulted more prevalently in the fPD group. CONCLUSIONS: fPD was found to recur more frequently than previously reported. Family history collection beyond the core family is essential to discover disease clusters and identify novel risk factors for PD.

Neurophysiological Aspects in SARS-CoV-2-Induced Acute Respiratory Distress Syndrome.

Patients with coronavirus disease 2019 (COVID-19) often develop acute respiratory failure and acute respiratory distress syndrome (ARDS) that requires intensive care unit (ICU) hospitalization and invasive mechanical ventilation, associated with a high mortality rate. In addition, many patients fail early weaning attempts, further increasing ICU length of stay and mortality. COVID-19 related ARDS can be complicated by neurological involvement with mechanisms of direct central nervous system (CNS) infection and with overlapping para-infective mechanisms of the peripheral nervous system (PNS). We aimed to evaluate the possible involvement of the brainstem and PNS in patients with COVID-19 related ARDS and difficulty in weaning from mechanical ventilation. We evaluated electroencephalogram (EEG), brainstem auditory evoked potentials (BAEPs), electroneurography of the four limbs and the phrenic nerve in 10 patients with respiratory insufficiency due to SARS-CoV-2. All were admitted to intensive care unit and were facing prolonged weaning from mechanical ventilation. All ten patients showed a mild diffuse non-specific slowing of brain electrical activity on the EEG. Four patients had an acute motor axonal neuropathy with absent or reduced amplitude phrenic nerve CMAP while four patients showed impairment of the BAEPs. A patient with peripheral nerve impairment suggestive of Guillain-Barré syndrome (GBS) underwent an intravenous immunoglobulin (IVIg) cycle that led to an improvement in the weaning process and progressive motor improvement. The inclusion of a comprehensive neurological evaluation in COVID-19 patients in ICU facilitated the early identification and effective management of Nervous System involvement.

Multicenter study report: electrophysiological monitoring procedures for subthalamic deep brain stimulation surgery in Parkinson's disease.

Despite the wide diffusion of subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease, systematic practical recommendations for intraoperative electrophysiological monitoring are still lacking. In this paper, a shared protocol for intraoperative electrophysiological monitoring arising from the meetings of a panel of neurophysiologists of the DBS Study Group of the Italian Neurological Society is proposed. Intraoperative monitoring is composed by microrecordings and functional stimulation. In microrecordings, it is recommended to use at least 2-3 electrodes, descending with steps of 0.5-1 mm and waiting at least 60 s before changing the position. Functional stimulation is used to assess the clinical efficacy and the side effects induced by STN-DBS at different positions. Based on the therapeutic window, an algorithm to find the optimal target is proposed. The procedures for intraoperative monitoring for STN-DBS proposed here are safe, relatively cheap, take approximately 30-40 min per side and could offer valuable additional information to the surgeon.

A multicentre study on suicide outcomes following subthalamic stimulation for Parkinson's disease.

Subthalamic nucleus deep brain stimulation improves motor symptoms and quality of life in advanced Parkinson's disease. As after other life-altering surgeries, suicides have been reported following deep brain stimulation for movement disorders. We sought to determine the suicide rate following subthalamic nucleus deep brain stimulation for Parkinson's disease by conducting an international multicentre retrospective survey of movement disorder and surgical centres. We further sought to determine factors associated with suicide attempts through a nested case-control study. In the survey of suicide rate, 55/75 centres participated. The completed suicide percentage was 0.45% (24/5311) and attempted suicide percentage was 0.90% (48/5311). Observed suicide rates in the first postoperative year (263/100,000/year) (0.26%) were higher than the lowest and the highest expected age-, gender- and country-adjusted World Health Organization suicide rates (Standardized Mortality Ratio for suicide: SMR 12.63-15.64; P < 0.001) and remained elevated at the fourth postoperative year (38/100,000/year) (0.04%) (SMR 1.81-2.31; P < 0.05). The excess number of deaths was 13 for the first postoperative year and one for the fourth postoperative year. In the case-control study of associated factors, 10 centres participated. Twenty-seven attempted suicides and nine completed suicides were compared with 70 controls. Postoperative depression (P < 0.001), being single (P = 0.007) and a previous history of impulse control disorders or compulsive medication use (P = 0.005) were independent associated factors accounting for 51% of the variance for attempted suicide risk. Attempted suicides were also associated (P < 0.05) with being younger, younger Parkinson's disease onset and a previous suicide attempt. Completed suicides were associated with postoperative depression (P < 0.001). Postoperative depression remained a significant factor associated with attempted and completed suicides after correction for multiple comparisons using the stringent Bonferroni correction. Mortality in the first year following subthalamic nucleus deep brain stimulation has been reported at 0.4%. Suicide is thus one of the most important potentially preventable risks for mortality following subthalamic nucleus deep brain stimulation for Parkinson's disease. Postoperative depression should be carefully assessed and treated. A multidisciplinary assessment and follow-up is recommended.

Motor and non-motor outcomes in patients with advanced Parkinson's disease treated with levodopa/carbidopa intestinal gel: final results of the GREENFIELD observational study.

INTRODUCTION: The GREENFIELD observational study assessed the effect of levodopa/carbidopa intestinal gel (LCIG) on motor and non-motor symptoms, and the related impact on patient quality of life and caregiver burden up to 8 years. METHODS: Final results of a large Italian cohort of patients who started LCIG in routine care between 2007 and 2014 are presented. Comparison between baseline (before LCIG) and follow-up visits on yearly basis (visit 2/3) is reported. Primary endpoint was Unified Parkinson's Disease Rating Scale (UPDRS-IV) Item 39; secondary endpoints were UPDRS I and II, dyskinesia items, PD Quality of Life Questionnaire-39, Parkinson's Disease Sleep Scale-2, Gait and Falls Questionnaire, Questionnaire on Impulsive Disorders, and Relative Stress Scale. RESULTS: Overall, 145 patients from 14 centers were assessed with a mean time since LCIG start of 2.8 ± 1.7 years at visit 2. The mean UPDRS-IV item 39 score showed significant reductions compared to baseline (mean score 2.0 ± 0.81) at visit 2 (mean score 0.9 ± 0.69; - 55%; p < 0.001) and at visit 3 (mean score 1.0 ± 0.75; - 50%; p < 0.001). At visit 3, significant reductions were observed for dyskinesia duration score (- 28%; p < 0.001), dyskinesia disability (- 40%; p < 0.001), and painful dyskinesia (- 50%; p < 0.001). Overall, 40 (27.6%) patients experienced 49 serious adverse events which were considered related to PEG/J procedure or to device in 16.3% of the cases. CONCLUSIONS: The results of this study support the long-term efficacy of LCIG on PD symptoms as well as on activities of daily living. The adverse events were consistent with the established LCIG safety profile.

Deep brain stimulation in Parkinson's disease: A multicentric, long-term, observational pilot study.

BACKGROUND: The impact of deep brain stimulation (DBS) on cognitive and urinary disorders, falls, and eventually hospitalizations and mortality in Parkinson's disease (PD) is still debated. OBJECTIVE: We compared the rates of dementia, mild cognitive impairment (MCI), urinary incontinence, nocturia, falls, hospitalizations, and mortality in a cohort of PD patients undergoing DBS with a cohort of medically-treated patients chosen as controls. METHODS: We conducted a retrospective pilot study in six Italian DBS centers. 91 PD patients receiving DBS and 91 age- and gender-matched controls receiving the best medical treatment alone with a minimum follow-up of one year were enrolled. Clinical data were collected from baseline to the last follow-up visit using an ad-hoc developed web-based system. RESULTS: The risk of dementia was similar in the two groups while patients in the surgical cohort had lower rates of MCI, urinary incontinence, nocturia, and falls. In contrast, the risk of hospital admissions related to PD was higher in the surgical cohort. However, when excluding hospitalizations related to DBS surgery, the difference between the two cohorts was not significant. The surgical cohort had a lower number of hospitalizations not related to PD. The risk of death was similar in the two groups. CONCLUSION: Despite a higher risk of hospitalization, patients receiving DBS had a lower rate of MCI, urinary incontinence, nocturia and falls, without evidence of an increased risk of dementia and mortality. Although these findings need to be confirmed in prospective studies, they seem to suggest that DBS may play a significant role in the management of non-motor symptoms and common complications of advanced PD.

Cost-effectiveness of 123I-FP-CIT SPECT in the differential diagnosis of essential tremor and Parkinson's disease in Italy.

Economic evaluation (Italian NHS perspective) modeling (123)I-FP-CIT SPECT (DaTSCAN) compared to clinical judgment alone for differentiating essential tremor (ET) from Parkinson's Disease (PD). A 5-year Markov model was constructed to assess the cost-effectiveness of (123)I-FP-CIT SPECT to differentiate ET from PD in patients referred to a movement disorder specialist in Italy. Published data and a double-round, Delphi panel of 12 specialists populated the model. Effectiveness was expressed as the projected Years on potentially beneficial therapy (PBTYs). Costs were expressed in Euros (2005 values). The model suggests that over 5 years, the "current" diagnostic pathway generated an average of 2.3 PBTYs/patient at an estimated cost of 8,864 euros. (123)I-FP-CIT SPECT generated an average of 4.1 PBTYs/patient at an estimated cost of 8,422 euros, which represented an additional 1.8 PBTYs at a cost saving of 442 euros/patient (341 euros when discounted at 5%). The estimated cost-effectiveness of (123)I-FP-CIT SPECT is under 1,000 euros per PBTY gained when the underlying disease prevalence is high (55-70%), and cost-saving at prevalence under 55%. (123)I-FP-CIT SPECT is likely to be regarded as economically advantageous to differentiate ET from PD, increasing time on potentially beneficial therapy at a lower overall cost to the healthcare system.

Extracellular spike microrecordings from the subthalamic area in Parkinson's disease.

Intraoperative neuronal microrecordings can help in localizing the subthalamic nucleus (STN) during stereotactic neurosurgery for deep-brain stimulation (DBS) in Parkinson's disease. To obtain quantitative information on neuronal spike descriptors, we systematically analysed neuronal spikes in the STN and substantia nigra pars reticulata (SNr) in 31 sides of the brain in awake patients undergoing stereotactic neurosurgery for DBS electrode implantation. In these two structures we evaluated spike amplitude, area, duration, rise time and mean total firing rate. The recording spike density was higher in the STN than in the SNr (94% vs. 28%). Microelectrode recordings showed a larger spike area and amplitude in the SNr than in the STN ([mean+/-SD] amplitude: 46.7+/-31.1 vs. 36.3+/-29.6 microV; area: 25.6+/-24.2 vs. 36.7+/-21.4 microVmsec), a higher total firing rate at rest in the SNr than in the STN (78.6+/-53.5 vs. 61.9+/-40.8 Hz), and a longer duration and rise time in the SNr than in the STN (duration: 2.0+/-1 vs. 1.3+/-0.6 ms; rise time: 0.95+/-0.6 vs. 0.67+/-0.3 ms). Our analysis also revealed sex-related differences in the studied spike descriptors, paralleling recent findings from deep electroencephalography recordings. In the STN, males had larger spike area and amplitude (amplitude: 41.97+/-32.57 vs. 26.2+/-19.7 microV; area: 31.8+/-26.4 vs. 13.0+/-10.6 microVmsec), whereas females had higher mean total firing rate (66.7+/-53.4 vs. 82.8+/-50.8 Hz). Our results have implications for clinical practice and the development of algorithms for the neurophysiological identification of the STN during stereotactic neurosurgery for Parkinson's disease, based on the on-line automated computation of multiple spike-variables.

Which patients discontinue? Issues on Levodopa/carbidopa intestinal gel treatment: Italian multicentre survey of 905 patients with long-term follow-up.

OBJECTIVES: To report the results of a national survey aimed at quantifying the current level of diffusion of Levodopa/carbidopa intestinal gel (LCIG) in Italy. METHODS: Sixty Parkinson's Disease (PD) specialists in Italy were invited to complete a survey covering issues on clinical and practical aspects of LCIG therapy. RESULTS: Clinical features of 905 patients were collected retrospectively. The majority of centres reported the use of a multidisciplinary team, biochemistry testing, neurophysiological and neuropsychological tests before and after treatment, in addition to caregivers' training and patient's follow as outpatients. Most centres (60%) used internal guidelines for patient selection. The overall rate of adverse events was 55.1%. Weight loss, chronic polyneuropathy and stoma infection were the most frequently reported. 40% of centres used replacement therapy with Vitamin B12 and Folic acid from the start of LCIG and continued this for the duration of treatment. The rate of discontinuation was of 25.7% overall, with 9.5% of cases occurring in the first year. The main causes of withdrawal were device-related complications, disease progression (comorbidity, severe dementia) and caregiver and/or patient dissatisfaction. CONCLUSIONS: In Italy LCIG infusion is managed in a uniform manner at a clinical, practical and organizational level even though the selection criteria are not standardized through the country. The high percentage of patients remaining on treatment in the short- and long-term follow-up confirms effectiveness of treatment, careful follow-up, and appropriate patient and caregivers training.

Pisa syndrome in Parkinson disease: An observational multicenter Italian study.

OBJECTIVE: To estimate the prevalence of Pisa syndrome (PS) in patients with Parkinson disease (PD) and to assess the association between PS and demographic and clinical variables. METHODS: In this multicenter cross-sectional study, consecutive outpatients with PD attending 21 movement disorders Italian tertiary centers were enrolled and underwent standardized clinical evaluation. PS was defined as trunk lateral deviation ≥10°. Patients with PD were compared according to the presence of PS for several demographic and clinical variables. RESULTS: Among 1,631 enrolled patients with PD, PS was detected in 143 patients (8.8%, 95% confidence interval 7.4%-10.3%). Patients with PS were older, had lower body mass index, longer disease duration, higher disease stages, and poorer quality of life. Falls were more frequent in the PS group as well as occurrence of "veering gait" (i.e., the progressive deviation toward one side when patient walked forward and backward with eyes closed). Patients with PS received higher daily levodopa equivalent daily dose and were more likely to be treated with combination of levodopa and dopamine agonists. Osteoporosis and arthrosis were significantly the most frequent associated medical conditions in patients with PS. Multiple explanatory variable logistic regression models confirmed the association of PS with the following variables: Hoehn and Yahr stage, ongoing combined treatment with levodopa and dopamine agonist, associated medical conditions, and presence of veering gait. CONCLUSIONS: Our results suggest that PS is a relatively frequent and often disabling complication in PD, especially in the advanced disease stages. The association is dependent on a number of potentially relevant demographic and clinical variables.

[Cost analysis in Italy of various strategies for the treatment of Parkinson disease in the advanced phase]. / Analisi dei costi, in Italia, di diverse strategie per il trattamento della malattia di Parkinson in fase avanzata.

OBJECTIVE: To perform a comparative economic evaluation of therapies--L-dopa drugs, subcutaneous infusion of apomorphine and surgical intervention of Deep Brain Stimulation (DBS)--for the treatment of advanced Parkinson's disease (APD) and to verify the level of assistance guaranteed in Italy to patients affected by APD. METHODS: Literature review and Delphi Panel to collect data about the efficacy of the therapies for the treatment of APD and the use of healthcare resources for such therapies. Field survey to investigate financing mechanisms of the therapeutical alternatives in the Italian regions; cost-analysis over five years (NHS perspective); cost-analysis (hospital perspective) for the initial administration of therapeutic alternatives. RESULTS: Literature review shows that the reduction of the "off-periods" is 62% for Apomorphine and 80-90% for DBS compared to traditional therapy. The 5-years economic analysis from the NHS perspective shows that the cost of a patients with APD is [symbol: see text] 58.065 if treated with traditional therapy, [symbol: see text] 36.423 (including infusional pump and the drug) with subcutaneous apomorphine and respectively [symbol: see text] 56.489 and [symbol: see text] 41.379 (depending on reimbursement of electrodes and neurostimulator on top of the DRG tariff) with DBS. The field survey, highlighted that Regions which currently reimburse the infusion pump for apomorphine and the electrodes and neurostimulator for DBS--on top of the DRG tariff--are a very limited number. CONCLUSIONS: Apomorphine and DBS in the treatment of APD show higher efficacy and lower costs compared to traditional therapy.

[Must we always treat hyperkalaemia?]. / Dobbiamo trattare sempre l'iperpotassiemia?

Pseudohyperkalaemia that occurs in conditions with raised platelet counts is caused by an in vitro rise of the serum potassium concentration during whole blood coagulation together with lysis of platelets and other cellular components, in the presence of normal renal function and plasma potassium levels. Here, we report the case of a 66-year-old man presenting a myeloproliferative disorder with thrombocythaemia. His serum potassium level was 6.4 mmol/L in the presence of normal renal function (creatinine clearance 78 mL/min) and a normal acid-base balance. Pseudohyperkalaemia in thrombocythaemia was suspected. Our suspicion was confirmed over the following three days by measuring potassium level in both a lithium heparin specimen tube (plasma sample) and in the serum. A clear-cut difference between serum potassium levels (mean 6.27 mmol/L) and plasma potassium levels (mean 4.10 mmol/L) was found. In conclusion, the aim of the present case report is to increase the awareness of the existence of pseudohyperkalaemia occurring in diseases that cause increased platelet counts in order to reduce the risk of potentially harmful treatment.

The effects of levodopa and ongoing deep brain stimulation on subthalamic beta oscillations in Parkinson's disease.

Local field potentials (LFPs) recorded through electrodes implanted in the subthalamic nucleus (STN) for deep brain stimulation (DBS) in patients with Parkinson's disease (PD) show that oscillations in the beta frequency range (8-20 Hz) decrease after levodopa intake. Whether and how DBS influences the beta oscillations and whether levodopa- and DBS-induced changes interact remains unclear. We examined the combined effect of levodopa and DBS on subthalamic beta LFP oscillations, recorded in nine patients with PD under four experimental conditions: without levodopa with DBS turned off; without levodopa with DBS turned on; with levodopa with DBS turned on; and with levodopa with DBS turned off. The analysis of STN-LFP oscillations showed that whereas levodopa abolished beta STN oscillations in all the patients (p=0.026), DBS significantly decreased the beta oscillation only in five of the nine patients studied (p=0.043). Another difference was that whereas levodopa completely suppressed beta oscillations, DBS merely decreased them. When we combined levodopa and DBS, the levodopa-induced beta disruption prevailed and combining levodopa and DBS induced no significant additive effect (p=0.500). Our observations suggest that levodopa and DBS both modulate LFP beta oscillations.