Paradoxical facilitation after depotentiation protocol can precede dyskinesia onset in early Parkinson's disease.

Loss of dopamine, a key modulator of synaptic signalling, and subsequent pulsatile non-physiological levodopa replacement is believed to underlie altered neuroplasticity in Parkinson's disease (PD). Animal models suggest that maladaptive plasticity (e.g. deficient depotentiation at corticostriatal synapses) is key in the development of levodopa-induced dyskinesia (LID), a common complication following levodopa replacement in PD. Human studies using transcranial magnetic stimulation protocols have shown similar depotentiation deficit in patients with LID. We hypothesized that subtle depotentiation deficits should precede LID if these deficits are mechanistically linked to LID onset. Moreover, patients on pulsatile levodopa-based therapy may show these changes earlier than those treated with levodopa-sparing strategies. We recruited 22 early non-dyskinetic PD patients (<5 years since diagnosis) and 12 age-matched healthy controls. We grouped patients into those on Levodopa-Based (n = 11) and Levodopa-Sparing therapies (n = 11). Patients were selected to obtain groups matched for age and disease severity. We used a theta-burst stimulation protocol to investigate potentiation and depotentiation in a single session. We report significant depotentiation deficits in the Levodopa-Based group, compared to both Levodopa-Sparing and Healthy Control groups. Potentiation and Depotentiation responses were similar between Levodopa-Sparing and Healthy Control groups. Although differences persist after accounting for potential confounds (e.g. levodopa-equivalent dose), these results may yet be caused by differences in disease severity and cumulative levodopa-equivalent dose as discussed in the text. In conclusion, we show for the first time that paradoxical facilitation in response to depotentiation protocols can occur in PD even prior to LID onset.

Clinical features and 123I-FP-CIT SPECT imaging in vascular parkinsonism and Parkinson's disease.

OBJECTIVES: To analyse the differences in the clinical features and characteristics of (123)I-labelled 2ß-carbomethoxy-3ß-(4-iodophenyl)-N-(3-fluoropropyl) nortropane ((123)I-FP-CIT) single photon emission CT (SPECT) imaging among patients with vascular parkinsonism (VP) and Parkinson's disease (PD). METHODS: We performed a case-control study to compare clinical features and qualitative and semi-quantitative analyses of (123)I-FP-CIT SPECT images between 106 patients with VP and 280 patients with PD. A case series study was used to search for clinical features related to SPECT or neuroimaging findings among patients with VP. RESULTS: Patients with VP had a higher age at symptom onset and lower disease duration than patients with PD. The most frequent symptom at onset was gait disorder in VP and tremor in PD. Gait disorder, postural instability and falls were more frequent in VP. Rest and mixed tremor were more prevalent in PD. Of the patients who received levodopa treatment in the VP group, only about half had a good response. Qualitatively (123)I-FP-CIT SPECT images were normal in 32.5% of patients with VP and abnormal in all patients with PD. The use of different visual score patterns showed higher ability to differentiate VP from PD. Semi-quantitative analysis showed significantly higher uptake in the striatum, caudate and putamen in VP. The asymmetry index was higher in patients with PD. Among patients with VP, falls were the only clinical feature that demonstrated a correlation with the SPECT visual pattern. CONCLUSION: Our data contribute to the confirmation that VP and PD are two different clinical entities. Neurological signs, response to treatment and qualitative and semi-quantitative (123)I-FP-CIT SPECT analyses may help to make the diagnosis.

Author Correction: Sensorimotor adaptation as a behavioural biomarker of early spinocerebellar ataxia type 6.

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Sensorimotor adaptation as a behavioural biomarker of early spinocerebellar ataxia type 6.

Early detection of the behavioural deficits of neurodegenerative diseases may help to describe the pathogenesis of such diseases and establish important biomarkers of disease progression. The aim of this study was to identify how sensorimotor adaptation of the upper limb, a cerebellar-dependent process restoring movement accuracy after introduction of a perturbation, is affected at the pre-clinical and clinical stages of spinocerebellar ataxia type 6 (SCA6), an inherited neurodegenerative disease. We demonstrate that initial adaptation to the perturbation was significantly impaired in the eighteen individuals with clinical motor symptoms but mostly preserved in the five pre-clinical individuals. Moreover, the amount of error reduction correlated with the clinical symptoms, with the most symptomatic patients adapting the least. Finally both pre-clinical and clinical individuals showed significantly reduced de-adaptation performance after the perturbation was removed in comparison to the control participants. Thus, in this large study of motor features in SCA6, we provide novel evidence for the existence of subclinical motor dysfunction at a pre-clinical stage of SCA6. Our findings show that testing sensorimotor de-adaptation could provide a potential predictor of future motor deficits in SCA6.

[Hemicrania continua and paroxysmal hemicrania: clinical and therapeutic characteristics in a series of 23 patients]. / Hemicránea continua y paroxística: características clínicas y terapéuticas en una serie de 23 pacientes.

INTRODUCTION: Hemicranias are an uncommon type of headache characterised by strictly unilateral pain, either as a continuous, although fluctuating, headache in hemicrania continua (HC) or in the form of recurring attacks in paroxysmal hemicrania (PH). In both types of headache, an absolute response to indomethacin is reported. AIMS. To analyse the fulfilment of current diagnostic criteria for HC and PH and the recent introduction of HC within the group of trigeminal-autonomic cephalgias. PATIENTS AND METHODS: The clinical and therapeutic characteristics of patients diagnosed with HC or PH were evaluated retrospectively. Demographic and symptomatological information as well as data regarding the analogical pain scale and response to indomethacin were included. RESULTS: A sample of 12 HC (four males and eight females) was evaluated from a total of 520 cases (2.3%). Mean age at onset: 47.1 ± 16.4 years. Baseline pain intensity: 3.3 ± 1,9. Exacerbations: 9.2 ± 1.1. Eight cases (66.7%) presented autonomic symptoms, four (33.3%) followed a time pattern, and two (16.7%) did not respond to indomethacin. We evaluated a sample of 11 PH (100% females) from 520 cases (2.1%). Mean age at onset: 37.0 ± 13.9 years. Pain intensity: 8.7 ± 2.7. Nine cases (81.8%) presented autonomic symptoms, three (27.3%) followed a time pattern and one (9.1%) did not respond to indomethacin. CONCLUSIONS: Hemicranias are not frequently diagnosed in day-to-day clinical practice. Their diagnosis requires the fulfilment of certain criteria that are sometimes not fully satisfied. We believe that the criteria need revising and we also support the recent inclusion of HC within the group of trigeminal-autonomic cephalgias.

TITLE: Hemicranea continua y paroxistica: caracteristicas clinicas y terapeuticas en una serie de 23 pacientes.Introduccion. Las hemicraneas son cefaleas raras caracterizadas por dolor estrictamente unilateral, bien como una cefalea continua, aunque fluctuante, en la hemicranea continua (HC), o en forma de ataques recurrentes en la hemicranea paroxistica (HP). En ambos tipos de cefalea se describe una respuesta absoluta a la indometacina. Objetivo. Analizar el cumplimiento de los criterios diagnosticos actuales para HC y HP, y la reciente introduccion de la HC en el grupo de las cefaleas trigeminoautonomicas. Pacientes y metodos. Evaluamos retrospectivamente las caracteristicas clinicas y terapeuticas de pacientes diagnosticados de HC o HP. Incluimos informacion demografica, sintomatologia, escala analogica de dolor y respuesta a la indometacina. Resultados. Evaluamos una muestra de 12 pacientes con HC (cuatro hombres y ocho mujeres) de un total de 520 casos (2,3%). Edad media de inicio: 47,1 ± 16,4 años. Intensidad de dolor basal: 3,3 ± 1,9. Exacerbaciones: 9,2 ± 1,1. Ocho casos (66,7%) presentaban sintomas autonomicos, cuatro (33,3%) tenian patron horario y dos (16,7%) no respondieron a la indometacina. Evaluamos una muestra de 11 pacientes con HP (100% mujeres) de 520 casos (2,1%). Edad media de inicio: 37,0 ± 13,9 años. Intensidad de dolor: 8,7 ± 2,7. Nueve casos (81,8%) presentaban sintomas autonomicos, tres (27,3%) tenian patron horario y uno (9,1%) no respondio a la indometacina. Conclusiones. Las hemicraneas son diagnosticos infrecuentes en consultas de cefalea. Su diagnostico requiere el cumplimiento de unos criterios que a veces no se cumplen en su totalidad. Pensamos que se precisa una revision de los criterios y apoyamos que la HC se haya introducido recientemente en el grupo de las cefaleas trigeminoautonomicas.

Clinical features and neuropsychological profile in vascular parkinsonism.

BACKGROUND: The clinical profile in vascular parkinsonism (VP) patients is well described in the literature, but little is known about the neuropsychological features of this disease. The aim of our study was to evaluate the clinical characteristics and the profile of cognitive impairment in patients with VP. METHODS: We prospectively evaluated 12 patients with VP, 15 with Parkinson's disease (PD) and 13 healthy controls (HC) with similar age and sex distribution. Different clinical and demographic details were collected. All subjects underwent detailed neurological and neuropsychological examinations. The neuropsychological tests included analysis of global efficiency, executive function, verbal memory, language and visuospatial function. RESULTS: VP patients exhibited lower disease duration, older age at onset and higher frequency of cardiovascular risk factors. Non-motor symptoms were found to be more frequent in PD. We found that VP patients developed cognitive impairment with a significantly higher frequency than HC of a similar age. Additionally, we found that these patients had a global pattern of cognitive impairment, including executive function, verbal memory and language. Only visuospatial function was more impaired in PD than in HC. CONCLUSIONS: Our data contribute to clarify the pattern of neuropsychological impairment in VP. Therefore, in the clinical evaluation, besides assessing the motor status of the patient, given that these symptoms are frequently found not to be self-reported complaints, the neurologist should evaluate them routinely as a comprehensive assessment of this disease.