Clinical neuroscience (New York, N.Y.)最新文献

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.

The importance of magnesium in the pathogenesis of migraine headaches is clearly established by a large number of clinical and experimental studies. However, the precise role of various effects of low magnesium levels in the development of migraines remains to be discovered. Magnesium concentration has an effect on serotonin receptors, nitric oxide synthesis and release, NMDA receptors, and a variety of other migraine related receptors and neurotransmitters. The available evidence suggests that up to 50% of patients during an acute migraine attack have lowered levels of ionized magnesium. Infusion of magnesium results in a rapid and sustained relief of an acute migraine in such patients. Two double-blind studies suggest that chronic oral magnesium supplementation may also reduce the frequency of migraine headaches. Because of an excellent safety profile and low cost and despite the lack of definitive studies, we feel that a trial of oral magnesium supplementation can be recommended to a majority of migraine sufferers. Refractory patients can sometimes benefit from intravenous infusions of magnesium sulfate.

Neuroimaging modalities in Parkinson's Disease (PD) are primarily used for the differential diagnosis of Parkinson syndromes and to understand pathophysiological mechanisms in PD. Neuroimaging of nonmotor dysfunctions in PD mostly consist of functional studies in neuropsychologically impaired PD patients using PET or SPECT techniques. Various studies controversially discuss the probable frontal versus temporal hypometabolism in demented PD patients. Functional studies of PD patients with depression are limited to case reports showing an involvement of left frontal regions. To investigate the pathophysiology of hallucinations with functional imaging may be a promising field of future research.

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.

According to recent evoked potential studies a fundamental, probably protective, feature of cortical information processing, i.e., response habituation during stimulus repetition, is abnormal in migraine between attacks. The deficient habituation is found for different sensory modalities and experimental paradigms: pattern-reversal visual evoked potentials (same stimulus at a constant intensity), cortical auditory evoked potentials (same stimulus at increasing intensities), and auditory event-related potential obtained in a passive "oddball" paradigm (novel stimulus). The abnormal information processing is an interictal cortical dysfunction most likely due to inadequate control by the so-called "state-setting, chemically-addressed pathways" originating in the brain stem, in particular by the serotonergic pathway, leading to a low preactivation level of sensory cortices. We propose that it may play a pivotal role in migraine pathogenesis in conjunction with the reported decrease of brain mitochondrial energy reserve, by favouring a rupture of metabolic homeostasis and biochemical shifts capable of activating the trigeminovascular system and, thus, of producing a migraine attack. We postulate that both the deficient habituation in information processing and the deranged oxygen metabolism may have behavioral correlates. Which of these abnormalities are inherited, acquired, or both remains to be determined.

Rapid technological advances in the field of molecular genetics are being applied successfully to the analysis of migraine. Specific mutations leading to an increased risk of rare forms of migraine have been identified in both mitochondrial DNA and a calcium channel gene. Association studies have demonstrated that polymorphic variations in serotonergic and dopaminergic genes may alter the clinical susceptibility to migraine. Massive amounts of additional genetic data relating to migraine will be generated in the next few years. These data are revolutionizing the diagnosis and management of migraine, a heretofore subjective clinical disorder.

Headache and mood disorders co-occur at significant rates. Two psychological techniques of proven effectiveness in treating headache are biofeedback and relaxation training. For treating the mood disorders that accompany chronic headache, cognitive-behavioral and pharmacological therapies are highly effective both individually and combined. The present article discusses the importance of treating anxiety-spectrum disorders as well as pain when treating headache, and of manipulating factors known to influence the probability of a patient's developing chronic pain and disability.

Sexual dysfunction is seen in a number of neurologic diseases. In this article we review normal human sexual response, some neurologic diseases in which sexual dysfunction is seen, and Parkinson's disease (PD). With PD there is often a reduction in sexual interest and function. The studies documenting these problems are detailed. In addition, we focus on the syndrome of hyper- or aberrant sexual function seen with pharmacotherapy of PD.

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.

Health-related quality of life (QoL) is becoming an important outcome measure in the field of migraine. Several generic and migraine-specific questionnaires have been evaluated for reliability and validity in migraine. The generic instruments demonstrate the severe impairment in the QoL of migraine patients compared to patients with other chronic diseases and to the general population. The migraine-specific instruments are designed to measure the short- and long-term impact of migraine on QoL and are responsive to changes in QoL secondary to migraine therapy. The widespread use of these standardized instruments can increase awareness of the burden of migraine and lead to improved therapeutic intervention for migraine.