Biomedical subjects

William Bara-Jimenez

Publications and source records attributed to William Bara-Jimenez.

9 recordsLinked to original sources

PubMed2006

Correlation between putative indicators of primary restless legs syndrome severity.

BACKGROUND AND PURPOSE: Several methods of assessing disease severity in restless legs syndrome (RLS) have been suggested. The purpose of this study was to examine the relationship between the suggested immobilization test (SIT), the International RLS Study Group rating scale (IRLS), sleep efficiency, and periodic leg movements of sleep index (PLMI). PATIENTS AND METHODS: Forty primary RLS patients with periodic leg movements of sleep were included in this prospective study. Study procedures were all performed during the same night, beginning with IRLS administration and following with SIT and polysomnography (PSG) evaluations, in that order. SIT was composed of two parameters: SIT mean discomfort score (SIT-MDS) and SIT periodic leg movements of wakefulness index (SIT-PLMW). PSG target measures were PLMI and sleep efficiency. Pearson's correlation was used for analysis at a P<0.01 significance level. RESULTS: PSG-PLMI correlated with IRLS (r=0.462; P=0.003) and with SIT-PLMW (r=0.681; P=0.0004). A correlation was also found between IRLS and SIT-MDS (r=0.447; P=0.004), even though SIT-PLMW and IRLS did not correlate with each other (P=0.286). A negative correlation was found between PSG-PLMI and sleep efficiency (r=-0.435; P=0.005). Neither SIT nor IRLS correlated with sleep efficiency. Only SIT discomfort scores from the second half of SIT correlated with SIT-PLMW (r=0.457, P=0.004), and they had a stronger correlation with IRLS (P=0.003). CONCLUSIONS: This study attempted a much needed comprehensive evaluation of the relationship between various RLS severity indicators. Our findings support a strong role of motor dysfunction on sleep quality in RLS, as well as the potential use of SIT-PLMW as a sensitive indicator of RLS severity.

Adolescent↗

PubMed2006

Widespread decrease of nicotinic acetylcholine receptors in Parkinson's disease.

OBJECTIVE: Nicotinic acetylcholine receptors have close interactions with the dopaminergic system and play critical roles in cognitive function. The purpose of this study was to compare these receptors between living PD patients and healthy subjects. METHODS: Nicotinic acetylcholine receptors were imaged in 10 nondemented Parkinson's disease patients and 15 age-matched healthy subjects using a single-photon emission computed tomography ligand [(123)I]5-iodo-3-[2(S)-2-azetidinylmethoxy]pyridine. Using an arterial input function, we measured the total distribution volume (V; specific plus nondisplaceable), as well as the delivery (K(1)). RESULTS: Parkinson's disease showed a widespread significant decrease (approximately 10%) of V in both cortical and subcortical regions without a significant change in K(1). INTERPRETATION: These results indicate the importance of extending the study to demented patients.

Aged↗

PubMed2006

Placebo-controlled study of rTMS for the treatment of Parkinson's disease.

The objective of this study is to assess the safety and efficacy of repetitive transcranial magnetic stimulation (rTMS) for gait and bradykinesia in patients with Parkinson's disease (PD). In a double-blind placebo-controlled study, we evaluated the effects of 25 Hz rTMS in 18 PD patients. Eight rTMS sessions were performed over a 4-week period. Four cortical targets (left and right motor and dorsolateral prefrontal cortex) were stimulated in each session, with 300 pulses each, 100% of motor threshold intensity. Left motor cortex (MC) excitability was assessed using motor evoked potentials (MEPs) from the abductor pollicis brevis. During the 4 weeks, times for executing walking and complex hand movements tests gradually decreased. The therapeutic rTMS effect lasted for at least 1 month after treatment ended. Right-hand bradykinesia improvement correlated with increased MEP amplitude evoked by left MC rTMS after individual sessions, but improvement overall did not correlate with MC excitability. rTMS sessions appear to have a cumulative benefit for improving gait, as well as reducing upper limb bradykinesia in PD patients. Although short-term benefit may be due to MC excitability enhancement, the mechanism of cumulative benefit must have another explanation.

Evoked Potentials, Motor↗

PubMed2006

Glutamate release inhibition ineffective in levodopa-induced motor complications.

Reported benefits of various glutamatergic receptor antagonists in Parkinson's disease (PD) prompted an evaluation of the antidyskinetic effect of a putative glutamate release inhibitor in 15 moderately advanced patients. In a 3-week, double-blind, proof-of-concept study, riluzole (200 mg/day) failed to alter parkinsonian or levodopa-induced motor complication severity. Opposing effects of a generalized inhibition of glutamate-mediated synaptic transmission may limit the usefulness of this approach to treat PD.

Aged↗

PubMed2005

Visual deprivation effects on human motor cortex excitability.

Single and paired-pulse transcranial magnetic stimulation (TMS) were applied to the motor cortex of 12 healthy volunteers, who were instructed to relax under eyes-open and eyes-closed conditions with room lights on and after 30 min of blindfolding. Compared to the eyes-open condition, significantly larger motor-evoked potentials and less intracortical inhibition were observed during blindfolding. Visual deafferentation changes resting human motor cortex excitability and might be a novel way to promote brain plasticity. These results raise the issue of how widespread the effects of temporary deafferentation may be and whether they are mediated by discrete or diffuse systems. These findings also illustrate an important potential confound in TMS studies of the motor cortex.

Darkness↗

PubMed2005

Effects of serotonin 5-HT1A agonist in advanced Parkinson's disease.

Intermittent stimulation of striatal dopaminergic receptors seems to contribute to motor dysfunction in advanced Parkinson's disease (PD). With severe dopaminergic denervation, exogenous levodopa is largely decarboxylated to dopamine in serotonergic terminals. If 5-HT1A autoreceptors regulate dopamine as well as serotonin release, in parkinsonian patients inhibition of striatal serotonergic neuron firing might help maintain more physiological intrasynaptic dopamine concentrations and thus ameliorate motor fluctuations and dyskinesias. To evaluate this hypothesis, effects of a selective 5-HT1A agonist, sarizotan, given orally at 2 and 5 mg twice daily to 18 relatively advanced parkinsonian patients, were compared with baseline placebo function during a 3-week, double-blind, placebo-controlled, proof-of-concept study. Sarizotan alone or with intravenous levodopa had no effect on parkinsonian severity. But at safe and tolerable doses, sarizotan coadministration reduced levodopa-induced dyskinesias and prolonged its antiparkinsonian response (P < or = 0.05). Under the conditions of this study, our findings suggest that 5-HT1A receptor stimulation in levodopa-treated parkinsonian patients can modulate striatal dopaminergic function and that 5-HT1A agonists may be useful as levodopa adjuvants in the treatment of PD.

Aged↗

PubMed2004

Effect of monoamine reuptake inhibitor NS 2330 in advanced Parkinson's disease.

Dopamine reuptake blockers, by enhancing and stabilizing intrasynaptic transmitter levels, could help palliate motor dysfunction in Parkinson's disease. This randomized, double-blind, placebo-controlled study compared the acute effects of the monoamine uptake inhibitor NS 2330 to those of placebo in 9 relatively advanced parkinsonian patients. At the dose administered, no change in parkinsonian scores was found when NS 2330 was given alone or with levodopa. Moreover, NS 2330 coadministration did not appear to alter dyskinesia severity or the duration of the antiparkinsonian response to levodopa. The drug was well tolerated. Under the conditions of this study, the present results failed to support the usefulness of dopamine reuptake inhibition in the treatment of advanced Parkinson's disease.

Aged↗

PubMed2002

Sensory training for patients with focal hand dystonia.

Some patients with focal hand dystonia have impaired sensory perception. Abnormal sensory processing may lead to problems with fine motor control. For patients with focal hand dystonia who demonstrate sensory dysfunction, sensory training may reverse sensory impairment and dystonic symptoms. We studied the efficacy of learning to read braille as a method of sensory training for patients with focal hand dystonia. Sensory spatial discrimination was evaluated in 10 patients who had focal hand dystonia and 10 age- and gender-matched controls with a spatial acuity test (JVP domes were used in this test). Clinical dystonia evaluation included the Fahn dystonia scale and time needed to write a standard paragraph. Each individual was trained in braille reading at the grade 1 level for 8 weeks, between 30 and 60 minutes daily, and was monitored closely to ensure that reading was done regularly. Both controls and patients demonstrated improvement on the spatial acuity test. Patients showed a significant mean difference from baseline to 8 weeks on the Fahn dystonia scale. Sixty percent of the patients shortened the time they needed to write a standard paragraph. Improved sensory perception correlated positively with improvement on the Fahn dystonia scale. We conclude that training in braille reading improves deficits in spatial discrimination and decreases disability in patients with focal hand dystonia.

Adult↗

PubMed2002

State dependent excitability changes of spinal flexor reflex in patients with restless legs syndrome secondary to chronic renal failure.

OBJECTIVE: Periodic limb movement in sleep (PLMS) is a common dysfunction of motor control during sleep, occurring either in isolation or associated with a variety of neurological disorders including restless legs syndrome (RLS). Although the PLMS generators have not been established, their occurrence in patients with spinal cord injury and their clinical resemblance to the spinal cord flexor withdrawal reflex (FR) suggest that PLMS may originate in the circuitry that mediates the FR. The significantly increased spinal cord excitability noted in primary RLS/PLMS patients may play an important role in the pathophysiology of primary RLS. The aim of this study is to establish whether the enhanced spinal cord excitability, which is represented by a lower threshold and/or greater spatial spread of the FR, is also true for the RLS/PLMS patients whose RLS is secondary to chronic renal failure (CRF). METHODS: Twenty patients with RLS/PLMS secondary to CRF have been compared with matched controls according to the state dependent changes in FR excitability. All patients met the diagnostic criteria for RLS and PLMS. They had CRF for 5.2+/-3.5 years, and were under the hemodialysis treatment. Twenty healthy, age and sex matched subjects were tested as controls. The electrophysiological testing of the FR was performed during wakefulness (9:30-10:30 p.m.) and sleep (beginning of stage II, the first sleep cycle). RESULTS: A significant increase in FR excitability was found in RLS/PLMS patients with CRF. This abnormality was prominent during sleep, which was also true for the primary RLS. CONCLUSIONS: Our results suggest that similar neuronal pathways are involved in primary and secondary RLS/PLMS patients. Our results also support that RLS/PLMS and FR share a common spinal mechanism.

Journal Article↗