Showing papers in "Clinical Neuroscience in 1998"

Gastrointestinal dysfunction in Parkinson's disease.

Abstract: Gastrointestinal dysfunction is a frequent and occasionally dominating symptom of Parkinson's disease (PD). Features of gastrointestinal dysfunction include disordered control of saliva, dysphagia, gastroparesis, constipation in the sense of decreased bowel movement frequency, and defecatory dysfunction necessitating increased straining and resulting in incomplete evacuation. Excess saliva accumulates in the mouth because of decreased swallowing frequency. Dysphagia develops in approximately 50% of patients and may be a reflection of both central nervous system and enteric nervous system derangement. Gastroparesis may produce a variety of symptoms, including nausea, and also may be responsible for some of the motor fluctuations seen with levodopa therapy. Bowel dysfunction in PD may be the result of both delayed colon transit and impaired anorectal muscle coordination.

Olfactory dysfunction in Parkinson's disease.

Abstract: The olfactory system is one of the nonmotor systems severely affected in Parkinson's disease (PD). Olfactory dysfunction occurs early in the disease process, is independent of disease stage, duration, and treatment. However, olfactory dysfunction appears to be dependent on disease subtype. Olfaction is mildly impaired or preserved in most of the parkinsonism-plus syndromes (PPS). This provides a means of differential diagnosis between typical PD and PPS. Olfactory function is impaired also in familial forms of parkinsonism in which the genetic defect is known. In familial parkinsonism, olfactory function is impaired in both typical PD and PPS phenotypes. Olfactory dysfunction does not appear to be a manifestation of dopamine deficiency. Olfactory dysfunction is also associated with other neurodegenerative diseases such as Alzheimer's disease (AD), Huntington's disease (HD), as well as with normal aging. The neuropathological changes observed in the olfactory system in PD and other neurodegenerative diseases appear to be disease-specific, raising the possibility that olfactory dysfunction may be the result of a central rather than a peripheral process. The cellular and molecular mechanisms underlying olfactory dysfunction in PD and other neurodegenerative diseases remain unknown.

Migraine headaches: epidemiology and comorbidity.

Abstract: Migraine imposes substantial burdens both on individual headache sufferers and on society. Prevalence studies reveal that the condition affects about 18% of women and about 6% of men. Prevalence is highest between the ages of 25 and 55, during the peak productive years. Despite the development of new and effective treatment options, migraine remains an underdiagnosed and undertreated condition. In this article, we review the incidence, prevalence, and distribution of migraine and the conditions which are comorbid with migraine.

Respiratory function in Parkinson's disease.

Abstract: This article reviews the spectrum of respiratory dysfunction in Parkinson's disease (PD). It includes the primary effects of PD on the ventilation, response to medications, and pulmonary complications of antiparkinson therapy. Primary pulmonary abnormalities include a restrictive change mainly secondary to chest wall rigidity and upper airway obstruction; both are responsive to dopaminergic modulation. Respiratory dyskinesia, a side effect of levodopa therapy, may produce both restrictive and dyskinetic ventilation. Therapy with ergot derivatives may result in pleuropulmonary fibrosis. Lastly, pulmonary infection as a consequence of disordered respiratory mechanics continues to contribute significantly to morbidity and mortality in PD.

Serotonin receptors and the acute attack of migraine.

Abstract: The development of serotonin (5HT) agonists that have highly specific receptor profiles has fuelled the study of 5HT receptor pharmacology and in particular the pharmacology of the 5HT(1) sub-class of receptors. The currently accepted classification of 5HT receptors includes seven classes known as 5HT(1) through 5HT(7) and the class most implicated in migraine 5HT(1), which consists of the A, B, D, E, and F sub-types. Currently, effective and relatively specific anti-migraine compounds, as a group, are potent 5HT(1B/1D) agonists. Their possible mechanisms of action include carotid territory vasoconstrictor effects and inhibitory effects on both the peripheral and central terminals of the trigeminal innervation of the pain-producing intracranial structures. Future drug development will target these individual mechanisms to dissect out which, if any, determines the clinical efficacy of the compounds. (C) 1998 Wiley-Liss, Inc.

Visuo-cognitive dysfunctions in Parkinson's disease.

Abstract: Loss of will, decreased activity, and poverty of behavior are among the common symptoms observed in Parkinson's disease (PD). In line with these clinical observations, PD patients display prominent deficit in neuropsychological tests, requiring self-generated and effort-demanding operations. However, recent evidence suggests that this impairment is not generalized: visuo-spatial working memory and attentional set-shifting seem to be selectively impaired in the early stages of the disease. Electrophysiological studies also demonstrate the dysfunction of higher-level visual information processing. In this article, we discuss some current results to show the connection between clinical symptoms and neuropsychological deficits. We also consider dysfunction in underlying neural mechanisms, with particular emphasis on the dysregulation of fronto-striatal circuits. However, it is conceivable that visuo-cognitive impairment in PD reflects dysfunction of neural assemblies, involving basal ganglia, dorsal visual stream, and frontal-prefrontal circuits.

Urinary dysfunction in Parkinson's disease.

Abstract: Urinary symptoms are very common in Parkinson's disease (PD). They are primarily irritative (frequency, urgency, urge incontinence) and correlate with the urodynamic finding of involuntary detrusor contractions at early stages of bladder filling (detrusor hyperreflexia). Obstructive symptoms (hesitancy, weak urinary stream) may be seen in a smaller number of patients by themselves or combined with irritative symptoms. They may be secondary to anticholinergics, obstructive uropathy, or point to the presence of multiple system atrophy. Dysfunction of the striated urethral sphincter and pelvic musculature can be seen in variable numbers in PD, with the main abnormality that of delayed relaxation at the time of initiation of voluntary voiding.

Neurophysiology of sensorimotor integration in Parkinson's disease.

Abstract: Parkinson's disease (PD) is a major neurologic disorder that distinctively and selectively affects movement and--by extension--the motor system. A large body of evidence has been accumulated over the years showing that movement disorders of PD are also due to sensory disturbances that affect sensorimotor integration. The aim of this review is to discuss the possible contribution of neurophysiologic techniques in evaluating the functionality of sensorimotor integration mechanisms in PD. Somatosensory evoked potentials (SEPs) are an appropriate functional approach for the evaluation of sensory processes in the human brain. SEPs from the frontal scalp sites are considered markers of the functionality of a cortico-subcortico-cortical loop that includes the basal ganglia as well as the premotor and supplementary motor areas. Over the years, it has been demonstrated that PD patients--especially in the early stages of the disease--show a severely depressed frontal responsiveness to sensory stimuli as tested via SEPs. The transient recovery of frontal SEP amplitude after apomorphine, a potent dopamine agonist drug, is a good and specific predictor of the clinical response of PD patients to L-dopa therapy.