Handbook of clinical neurology最新文献

Anesthesia for the resection of vestibular schwannomas poses unique challenges; operative times are long, typically between 8 and 12h, during which there are varying levels of surgical stimulation. Close attention to positioning is essential to minimize skin damage, neuropraxia, and optimize surgical access. The delicate nature of microsurgical resection requires absolute patient immobility; this is made more demanding by the need to avoid neuromuscular blocking drugs to facilitate continuous electromyographic (EMG) monitoring of the facial nerve. The choice of anesthetic should enable this and allow for prompt postoperative assessment of neurologic function after prolonged exposure to these agents. Surgery on the vestibular apparatus can be a potent stimulus for postoperative nausea and vomiting, and postoperative control of these symptoms is important in order to optimize recovery.

Imaging plays a central role in the modern management of vestibular schwannomas (VS), from the initial diagnosis to treatment planning and subsequent monitoring of treatment response. It is of particular importance in NF2-related schwannomatosis (NF2) and similar genetic tumor predisposition syndromes, where patients require serial monitoring for many years. Magnetic resonance imaging (MRI) is the technique of choice and can reliably detect very small tumors and incremental growth. Modern imaging methods are reviewed, with a focus on MRI. The authors examine the initial evaluation of VS, differential diagnosis, expected posttreatment appearances, imaging after implantation, surveillance imaging, and assessment of complications. They also discuss imaging considerations arising in the context of NF2.

Tinnitus is the second most common presenting symptom of vestibular schwannoma (VS) after hearing loss. There is conflicting evidence regarding the impact of tinnitus and its contribution to the overall quality of life in VS, and there are many theories regarding the pathogenesis of tinnitus in VS, including cochlear, neural, and central mechanisms. Assessment should include speech audiometry in addition to pure-tone audiometry, as VS patients often have worse speech discrimination than would be expected from their pure-tone thresholds. There is no objective measure of tinnitus. Questionnaires may be used to assess the impact of tinnitus and its common comorbidities. Management of VS-associated tinnitus starts with explanation and counseling. Addressing hearing loss is often helpful: if the affected ear still has useful hearing, conventional hearing aids may be used. If there is no useful hearing on the affected side, contralateral routing of signal (CROS) hearing aids, bone conduction hearing implants (BCHI), or cochlear implantation may be beneficial. For patients with bilateral profound hearing loss following VS surgery, auditory brainstem implantation may help. Psychologic therapies, including cognitive behavioral therapy and mindfulness-based cognitive therapy, are commonly recommended for use in general tinnitus clinics, although there is no evidence base supporting these modalities for VS patients.

The glial control of energy homeostasis is of crucial importance for health and disease. Astrocytes in particular play a major role in controlling the equilibrium among adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), and adenosine. Any energy crisis leads to a drop in ATP, and the resulting increase in adenosine is an evolutionary ancient mechanism to suppress energy-consuming activities. The maintenance of brain energy homeostasis, in turn, requires the availability of energy sources, such as glucose and ketones. Astrocytes have assumed an important role in enabling efficient energy utilization by neurons. In addition, neurons are under the metabolic control of astrocytes through regulation of glutamate and GABA levels. The intricate interplay between glial brain energy metabolism and brain function can be best understood once the homeostatic system of energy metabolism is brought out of control. This has best been studied within the context of epilepsy where metabolic treatments provide unprecedented opportunities for the control of seizures that are refractory to conventional antiseizure medications. This chapter will discuss astroglial energy metabolism in the healthy brain and will use epilepsy as a model condition in which glial brain energy homeostasis is disrupted. We will conclude with an outlook on how those principles can be applied to other conditions such as Alzheimer disease.

As in the treatment of other pain conditions, the placebo and nocebo effects play an important role in the treatment of primary headache disorders, which are the most prevalent neurologic conditions worldwide with enormous personal and societal burden. Meta-analyses of randomized controlled trials (RCTs) for migraine prophylaxis revealed that 8 out of 20 participants treated with placebo experienced adverse events (AEs) and 1 out of 20 participants treated with placebo withdrew treatment because of AEs. Notably, the AEs in placebo groups mirrored the AEs expected of the medication in test, confirming that pretrial suggestions during the briefing of the participants by the researchers on the safety of the drug under test and the written consent to participate boost up the AEs in placebo-treated participants. In migraine RCTs, nocebo and placebo responses vary by the treatment duration, for example, nocebo response was higher in prophylactic than in symptomatic treatments, by treatment root of administration, for example, among prophylactic migraine treatments botulin toxin A showed the lowest nocebo response and the higher placebo response. Generally, the safer a treatment was (e.g., the less AEs recorded in the active treatment group) the less nocebo response was recorded (e.g., the less AEs recorded in the placebo treatment group). Nocebo and placebo responses were similar in trials for tension-type headache, but there is not enough evidence for cluster headache. To predict and prevent nocebo consequences a four-item self-fulfilled questionnaire (Q-No) has been developed, with 72% specificity and 67% sensitivity. This tool may help both investigators and practitioners to predict potential nocebo-behaviors and build personalized strategies to limit it, since nocebo effects are hampering treatment adherence and improve bad outcomes, in contrast to placebo effects. Large campaigns aiming to educate both physicians and citizens on the role of placebo and nocebo effects in medical therapeutics are required to improve headaches and public health, for example, vaccination and pharmaceutical prevention of several metabolic and vascular conditions.

This chapter delves into the multifaceted role of placebo effects in mental disorders, highlighting their impact on treatment outcomes across a spectrum of conditions, including depression, anxiety, schizophrenia, and bipolar disorder. Placebo responses, often seen as the intersection of psychological and physiological healing mechanisms, are critically examined through systematic reviews and meta-analyses that compare placebo effects to active treatments. The findings underscore substantial placebo effects, particularly in depression and anxiety, where these effects are often comparable to those of pharmacological interventions. The chapter also explores the variability of placebo effects across different disorders and the implications for clinical practice, suggesting that understanding these effects could lead to more tailored and effective therapeutic approaches. Additionally, the discussion includes the potential of open-label placebos, the influence of patient expectations, and the role of the clinician-patient relationship in enhancing treatment outcomes. By dissecting these elements, the chapter aims to pave the way for integrating placebo mechanisms into clinical practice, thereby enhancing the overall effectiveness of mental health treatments.

The incidence of vestibular schwannoma (VS) is increasing and patients with VS often have few symptoms. The aim of this chapter is to provide a framework for assessment and investigation of patients with sporadic vestibular schwannoma. Typical presentations, such as asymmetric sensorineural hearing loss, tinnitus, and balance disturbance, will be discussed, as well as atypical symptoms, highlighting potential red flags that could be the patients' only presenting symptom. An evidence-based approach to investigating patients with VS is discussed. This chapter explores the potential benefit of performing vestibular assessments in patients who are about to undergo surgical treatment and examines how a comprehensive initial evaluation of patients influences patient recovery and outcomes following surgery.