Persistence of Basal Ganglia Oscillatory Activity During Tremor Attenuation by Movement in Parkinson's Disease Patients.

BACKGROUND: One of the characteristics of parkinsonian tremor is that its amplitude decreases with movement. Current models suggest an interaction between basal ganglia (BG) and cerebello-thalamo-cortical circuits in parkinsonian tremor pathophysiology. OBJECTIVE: We aimed to correlate central oscillation in the BG with electromyographic activity during re-emergent tremor in order to detect changes in BG oscillatory activity when tremor is attenuated by movement. METHODS: We performed a prospective, observational study on consecutive parkinsonian patients who underwent deep brain stimulation surgery and presented re-emergent tremor. Coherence analysis between subthalamic nucleus/globus pallidus internus (STN/GPi) tremorous activity measured by microrecording (MER) and electromyogram (EMG) from flexor and extensor wrist muscles during rest, posture, and re-emergent tremor pause was performed during surgery. The statistical significance level of the MER-EMG coherence was determined using surrogate data analysis, and the directionality of information transfer between BG and muscle was performed using entropy transfer analysis. RESULTS: We analyzed 148 MERs with tremor-like activity from 6 patients which were evaluated against the simultaneous EMGs, resulting in 296 correlations. Of these, 26 presented a significant level of coherence at tremor frequency, throughout rest and posture, with a complete EMG stop in between. During the pause, all recordings showed sustained MER peaks at tremor frequency (±1.5 Hz). Information flows preferentially from BG to muscle during rest and posture, with a loss of directionality during the pause. CONCLUSIONS: Our results suggest that oscillatory activity in STN/GPi functionally linked to tremor sustains firing frequency during re-emergent tremor pause, thus suggesting no direct role of the BG circuit on tremor attenuation due to voluntary movements. © 2024 International Parkinson and Movement Disorder Society.

Re-emergent tremor provocation.

INTRODUCTION: Rest and re-emergent tremor (RET) in Parkinson's disease (PD) are known to be markedly variable. The aim of this study is to evaluate the effect of tremor provocation on RET latency and variability. METHODS: We performed a prospective observational study in 21 PD patients with RET. Evaluations were conducted by accelerometric analysis of hand movements with and without provocation by counting out loud backwards from 100, in the OFF state. Differences in RET pause duration, tremor power at peak frequency, root mean square (RMS) and slope of return of the tremor after the pause was measured. Inter- and intra-subject variability were also calculated. RESULTS: RET pause duration showed a 75% decrease after provocation (p < 0.001), which led to zero in 52% of cases, as compared to 9% in unprovoked measurements (p < 0.001). Provocation also led to a 2.57 time increase in tremor power (p < 0.001), 1.37 time increase in RMS (p < 0.001) and 2.47 time increase in slope (p < 0.001). A significant decrease in inter-subject variability was also observed (p = 0.001). CONCLUSION: Tremor provocation led to RET amplitude increase, pause shortening, and variability decrease. Therefore, while provocation can be recommended for the evaluation of rest tremor in clinical practice, it might well annul its value for identifying the pause prior to re-emergent tremor.

Headache in Patients with Celiac Disease and Its Response to the Gluten-Free Diet.

AIMS: To describe headache characteristics among celiac disease (CD) patients and to analyze the relationship between CD and headache. METHODS: An online survey analyzing the characteristics of headache and its response to the gluten-free diet (GFD) in celiac patients was published on Argentinean Celiac social networks, open to the public to complete. The results were analyzed using chi-square test or Mann-Whitney test accordingly. RESULTS: A total of 1,517 subjects completed the survey, and 866 (55.2%) met the inclusion criteria (headache and CD confirmed with positive biopsy). The subjects were predominantly female (94.5%) and had a median age of 39 ± 11.27 years. Tension-type headache was the most prevalent headache type (52%), followed by migraine without (32.5%) and with aura (15.4%), respectively. Of the included participants, 24% reported headache as the main symptom that resulted in the diagnosis of CD. Following initiation of GFD, headache frequency and intensity improved significantly more in participants with migraine than tension-type headache (P = .02 and P = .013, respectively). Compliance to GFD was higher among subjects with severe manifestations (77% vs 66%, P = .05), and compliant individuals showed a 48% improvement in headache frequency (P = .049). An association between food transgressions and headache was better recognized by migraineurs (P = .02). CONCLUSION: These results suggest that strict compliance to the GFD could improve headache in celiac patients with headache, even in those without gastrointestinal symptoms. This observation could provide an additional factor when convincing patients to follow a GFD, thus reducing the morbidity related to CD.

Sensitivity and specificity of different hand positions to assess upper limb rest tremor.

BACKGROUND: Hand position for rest tremor evaluation in PD is not standardized. We evaluated the sensitivity and specificity of different hand positions commonly used to evaluate rest tremor. METHODS: Twenty patients with PD and rest tremor were included as cases and 20 patients with essential tremor without rest tremor as controls. Video and accelerometric recordings were conducted in semiprone, completely prone, and with hands hanging down from armrest positions. Three movement disorder specialists rated tremor in each different position using Movement Disorder Society UPDRS items 3.17 and 3.18. RESULTS: Hands hanging showed the highest amplitude (P = 0.004) and constancy (P = 0.015) scores. Sensitivity and specificity analysis for each position showed the following sensitivity/specificity results: semiprone, 95%/80%; completely prone, 85%/98.33%; and hands hanging, 96.66%/63.33%, respectively. CONCLUSIONS: The hands-hanging position was shown to be the most suitable for evaluating rest tremor amplitude in PD, whereas the completely prone position proved to be more specific to detect rest tremor. The preferred hand position would depend on the purpose of the examination. © 2019 International Parkinson and Movement Disorder Society.

Latency of re-emergent tremor in Parkinson's disease is influenced by levodopa.

INTRODUCTION: Re-emergent tremor (RET) is a common form of postural tremor observed in Parkinson's disease (PD) patients. Recent studies have shown that administration of levodopa decreases RET amplitude. However, drug effects on tremor pause duration are less clear. METHODS: We performed a prospective observational study in PD patients with RET, subjected to acute levodopa challenge. Tremor activity was measured during OFF and ON states both clinically, as well as by using accelerometers taped to the back of both hands. Correlation between RET amplitude and pause duration, as well with MDS-UPDRS scores were investigated. The slope of gradual increase of postural tremor after the pause was also measured in the OFF and ON states. RESULTS: Significant inverse correlation between tremor amplitude and RET pause duration was observed in OFF (rs = -0.474, p = 0.030) and ON (rs = -0.569, p = 0.006) states. Levodopa reduced tremor amplitude (26%, p = 0.004) dampening slope gradient (22%, p = 0.029). Tremor pause duration also showed inverse correlation with postural tremor amplitude measured by MDS-UPDRS in OFF (rs = -0.311, p = 0.048) and ON (rs = -0.503, p = 0.020) states, as well as with total MDS-UPDRS Part III score (rs = -0.295, p = 0.009). Finally, accelerometric analysis proved to be more sensitive than visual inspection for detecting tremor pauses. CONCLUSION: Our results suggest RET pause duration is amplitude related, since levodopa-induced amplitude decrease led to pause prolongation, associated with decreased tremor intensity and slope gradient dampening.

Clinical Correlations of Positive Herpes Simplex PCR in Cerebrospinal Fluid.

OBJECTIVES: Herpes simplex viruses (HSV) can produce encephalitis (HSE), which requires early detection, typically using polymerase chain reaction (PCR) in cerebrospinal fluid (CSF). However, other neurological conditions not directly caused by HSV may also present with a positive HSV PCR in the CSF (NCNHPCR+). We aimed to analyze the clinical features of both groups of patients (HSE vs. NCNHPCR+) and to consider the potential relevance of this finding in the latter. METHODS: A retrospective analysis of clinical presentation, workup (CSF, EEG, and MRI) and outcome of patients with an HSV+ result in CSF was conducted from Jan-2007 to Sep-2015 in our institution. Patients under 18 years and those with nonencephalitic HSV associated disorders were excluded. Group comparison between HSE and NCNHPCR+ patients was conducted using parametric and nonparametric tests accordingly. RESULTS: Sixteen HSE and 23 NCNHPCR+ patients were included. Patients with HSE presented a higher incidence of headache (87.5% vs. 43.5%; P=0.008), meningeal symptoms (50% vs. 17.4%; P=0.04), pleocytosis (75% vs. 18%; P=0.001), EEG abnormalities (46.67% vs. 22%; P=0.02) and typical MRI findings (50% vs. 0%; P<0.001), whereas 35% of patients with NCNHPCR+ had an underlying immunologic disorder (35% vs. 0%; P=0.012). CONCLUSIONS: The pathogenic role of HSV in NCNHPCR+ is uncertain. This finding must be interpreted in the appropriate clinical, EEG, and neuroimaging context. Immunocompromise and neuroinflammation states could be related to a higher presence of HSV in CSF.

Differences between acute-onset chronic inflammatory demyelinating polyneuropathy and acute inflammatory demyelinating polyneuropathy in adult patients.

Acute inflammatory demyelinating polyneuropathy (AIDP) and acute-onset chronic inflammatory demyelinating polyneuropathy (A-CIDP) are conditions presenting overlapping clinical features during early stages (first 4 weeks), although the latter may progress after 8 weeks. The aim of this study was to identify predictive factors contributing to their differential diagnosis. Clinical records of adult patients with AIDP or A-CIDP diagnosed at our institution between January 2006 and July 2017 were retrospectively reviewed. Demographic characteristics, clinical manifestations, cerebrospinal-fluid (CSF) findings, treatment and clinical evolution were analyzed. Nerve conduction studies were performed in all patients with at least 12 months follow-up. A total of 91 patients were included (AIDP, n = 77; A-CIDP, n = 14). The median age was 55.5 years in patients with A-CIDP vs 43 years in AIDP (P = .07). The history of diabetes mellitus was more frequent in A-CIDP (29% vs 8%, P = .04). No significant differences between groups were observed with respect to: human immunodeficiency virus (HIV) status, presence of auto-immune disorder or oncologic disease. Cranial, motor and autonomic nerve involvement rates were similar in both groups. Patients in the A-CIDP group showed higher frequency of proprioceptive disturbances (83% vs 28%; P < .001), sensory ataxia (46% vs 16%; P = .01), and the use of combined immunotherapy with corticoids (29% vs 3%; P = .005). There were no significant differences in CSF findings, intensive care unit (ICU) admission, or mortality rates. During the first 8 weeks both entities are practically indistinguishable. Alterations in proprioception could suggest A-CIDP. Searching for markers that allow early differentiation could favor the onset of corticotherapy without delay.

Clinical and cerebrospinal fluid findings contribute to the early differentiation between infectious and noninfectious encephalitis.

Early recognition and prompt specific treatment are crucial factors influencing the outcome of patients with acute encephalitis. The aim of this study was to determine the main causes of acute encephalitis in our population and to find predictors that may lead to specific diagnosis. Adult patients admitted to our hospital with suspected diagnosis of encephalitis in the period 2006-2013 were included. One hundred and five medical records were analyzed. Eighty-two patients with infectious encephalitis were identified (78% of total cases), 53 (65%) men and 29 (35%) women, mean age 47.8 years. The most common microorganisms identified were: HSV-1 (11%), VZV (10%), HSV-2 (5%) and EBV (5%). Twenty-three patients (22% of the series) had non-infectious encephalitis. Headache (p < 0.0001) and fever (p = 0.008) were more frequent in encephalitis of infectious origin. Protein levels and white blood cell counts in the cerebrospinal fluid were significantly higher in patients affected by infectious encephalitis than in those affected by noninfectious encephalitis (OR 95% CI 12.3 [2.9-51.7] and OR 95% CI 7.4 [2-27], respectively). Identifying specific causal agents of acute encephalitis remains a major challenge. Cerebrospinal fluid markers, as well as specific clinical findings, may however contribute to initial differentiation between infectious and noninfectious causes.

Clinical and cerebrospinal fluid findings contribute to the early differentiation between infectious and noninfectious encephalitis

Early recognition and prompt specific treatment are crucial factors influencing the outcome of patients with acute encephalitis. The aim of this study was to determine the main causes of acute encephalitis in our population and to find predictors that may lead to specific diagnosis. Adult patients admitted to our hospital with suspected diagnosis of encephalitis in the period 2006-2013 were included. One hundred and five medical records were analyzed. Eighty-two patients with infectious encephalitis were identified (78% of total cases), 53 (65%) men and 29 (35%) women, mean age 47.8 years. The most common microorganisms identified were: HSV-1 (11%), VZV (10%), HSV-2 (5%) and EBV (5%). Twenty-three patients (22% of the series) had non-infectious encephalitis. Headache (p < 0.0001) and fever (p = 0.008) were more frequent in encephalitis of infectious origin. Protein levels and white blood cell counts in the cerebrospinal fluid were significantly higher in patients affected by infectious encephalitis than in those affected by noninfectious encephalitis (OR 95% CI 12.3 [2.9-51.7] and OR 95% CI 7.4 [2-27], respectively). Identifying specific causal agents of acute encephalitis remains a major challenge. Cerebrospinal fluid markers, as well as specific clinical findings, may however contribute to initial differentiation between infectious and noninfectious causes.

El reconocimiento temprano y la instauración del tratamiento adecuado son dos elementos de gran relevancia en el pronóstico de las encefalitis agudas. El objetivo del presente trabajo es determinar las principales causas de encefalitis aguda en nuestro medio, así como buscar predictores que permitan orientar a un diagnóstico determinado. Se revisaron de manera retrospectiva las historias clínicas de todos los pacientes adultos que consultaron en nuestro centro entre 2006 y 2013 con el diagnóstico presuntivo de encefalitis. Ciento cinco pacientes fueron finalmente incluidos en nuestro estudio. Se identificaron 82 pacientes con encefalitis de origen infeccioso (78%), 53 (65%) fueron hombres y 29 (35%) mujeres, con una edad promedio de 47.8 años. Los agentes infecciosos más frecuentes fueron virus: HSV-1 12 (11%), VZV 11 (10%), HSV-2 5 (5%) y EBV 5 (5%). Se diagnosticó encefalitis no infecciosa en 23 (22%) pacientes. La cefalea (p < 0.0001) y la fiebre (p = 0.008) fueron más frecuentes en las encefalitis de origen infeccioso. Además, los niveles de proteínas y células en el LCR fueron significativamente mayores en los casos de etiología infecciosa que en los de etiología no infecciosa (OR 12.3 95%CI [2.9-51.7] y OR 7.4 95%CI [2-27], respectivamente). La identificación de la etiología específica de las encefalitis agudas continúa siendo un gran desafío y en la mayoría de los casos no se identifica el agente causal. Determinados marcadores en el LCR pueden contribuir a la identificación inicial de las encefalitis de etiología infecciosa versus no infecciosa.

Age may contribute to the increased frequency of axonal Guillain-Barré syndrome.

INTRODUCTION: The frequency of axonal Guillain-Barré syndrome (GBS) varies among countries. Previous studies supporting the high frequency of axonal GBS in South America have been carried out with pediatric populations. We seek to determine the frequency of axonal GBS in both children and adults in South America. METHODS: This is a retrospective cohort analysis of patients who were diagnosed with GBS between January 2006 and December 2013 in a neurological center in Buenos Aires, Argentina. Adults and children with a diagnosis of GBS were included and classified by applying Ho and colleagues' criteria1 for axonal GBS. RESULTS: The study included 105 patients with GBS. Among 58 adults, only 5 individuals were classified as axonal GBS compared with 16 of 47 children. The frequency of axonal GBS was significantly higher in children than in adults (34% vs. 8.6%, P = 0.0001). DISCUSSION: As shown in a cohort of South American patients, age may impact the frequency of axonal GBS. Muscle Nerve 56: 1311-1313, 2017.

Facial tremors in patients with and without parkinsonism.

Facial (lip and jaw) tremors can be an early sign of Parkinson's disease (PD), essential tremor and other parkinsonisms. Its response to acute dopaminergic therapy and further predictive clinical diagnosis has not been previously addressed. The aim of this study was to evaluate facial tremors response to acute dopaminergic therapy and further predictive value for clinical diagnosis. A retrospective review of medical records from patients with recent onset of facial tremor, with or without parkinsonism, submitted to acute levodopa challenge for clinical prediction of sustained long-term dopaminergic response was conducted. Twenty-eight out of 559 patients (5 %) had facial tremors, which responded to levodopa in 46 % of patients. Facial tremors response to acute levodopa challenge showed 92 % sensitivity and 93 % specificity to predict a final PD diagnosis. In PD patients, facial tremor magnitude of response to levodopa was not different from that of hand rest tremor (p = 0.8). Facial tremors, although infrequent, can be an early sign of PD. Positive response to acute levodopa challenge predicts long-term PD diagnosis.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in Argentina.

CADASIL is the most common cause of hereditary stroke and vascular dementia. Published information about this disease in South America is scant. We describe clinical and demographic characteristics of 13 patients (10 families) with CADASIL from Argentina.Methods Medical records, diagnostic tests and family history of patients with CADASIL were reviewed.Results Thirteen patients with CADASIL (10 families) were included. All patients had European ancestry. Initial presentation was stroke in most patients (n = 11). Stroke patients later developed cognitive complaints (n = 9), migraine with aura (n = 1), apathy (n = 4) and depression (n = 6). External capsule and temporal lobe involvement on MRI were characteristic imaging findings. Two patients died after intracerebral hemorrhage.Conclusion This is the first report of non-related patients with CADASIL in South America addressing ancestry. Since European ancestry is not highly prevalent in all South American countries, there may be variable incidence of CADASIL within this region.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in Argentina / Arteropatia cerebral autosomal dominante com infartos subcorticais e leucoencefalopatia (CADASIL) na Argentina

CADASIL is the most common cause of hereditary stroke and vascular dementia. Published information about this disease in South America is scant. We describe clinical and demographic characteristics of 13 patients (10 families) with CADASIL from Argentina.Methods Medical records, diagnostic tests and family history of patients with CADASIL were reviewed.Results Thirteen patients with CADASIL (10 families) were included. All patients had European ancestry. Initial presentation was stroke in most patients (n = 11). Stroke patients later developed cognitive complaints (n = 9), migraine with aura (n = 1), apathy (n = 4) and depression (n = 6). External capsule and temporal lobe involvement on MRI were characteristic imaging findings. Two patients died after intracerebral hemorrhage.Conclusion This is the first report of non-related patients with CADASIL in South America addressing ancestry. Since European ancestry is not highly prevalent in all South American countries, there may be variable incidence of CADASIL within this region.

CADASIL é a causa mais frequente de acidente vascular cerebral e demência hereditários. São poucas as publicações sobre esta doença na América do Sul. Aqui descrevemos dados clínicos e demográficos de 13 pacientes (10 famílias) da Argentina com CADASIL.Métodos Prontuários médicos testes diagnósticos e história familiar de pacientes com CADASIL foram revisados.Resultados Treze pacientes com CADASIL (10 famílias) foram incluídos. Todos os pacientes tinha ancestralidade europeia. A apresentação inicial foi acidente vascular cerebral na maioria dos pacientes (n = 11). Pacientes com acidente vascular cerebral depois desenvolveram alterações cognitivas (n = 9), enxaqueca com aura (n = 1), apatia (n = 4) e depressão (n = 6). Os achados de imagem característicos da RM foram na cápsula externa e no lobo temporal. Dois pacientes morreram por hemorragia intracerebral.Conclusão Este é o primeiro relato de série de casos de pessoas não relacionadas entre si que apresentavam CADASIL na América do Sul, discutindo ancestralidade. Uma vez que a ascendência europeia tem prevalência variada em diferentes países da América do Sul, é possível que esta seja uma variável de incidência de CADASIL nesta região.