Pharmacological treatment of pain in multiple sclerosis

Individual Cerebral Blood Flow Responses to Transcranial Direct Current Stimulation at Various Intensities

Transcranial direct current stimulation (tDCS) has been shown to alter cortical excitability. However, it is increasingly accepted that tDCS has high inter- and intra-subject response variability, which currently limits broad application and has prompted some to doubt if the current can reach the brain. This study reports individual cerebral blood flow responses in people with multiple sclerosis and neurologically healthy subjects that experienced 5 min of anodal tDCS at 1 mA, 2 mA, 3 mA, and 4 mA over either the dorsolateral prefrontal cortex (DLPFC) or the primary motor cortex (M1). The most notable results indicated anticipated changes in regional cerebral blood flow (rCBF) in two regions of one DLPFC subject (2 mA condition), and expected changes in one M1 subject in the 2 mA and 4 mA conditions and in another M1 subject in the 2 mA condition. There were also changes contrary to the expected direction in one DLPFC subject and in two M1 subjects. These data suggest the effects of tDCS might be site-specific and highlight the high variability and individualized responses increasingly reported in tDCS literature. Future studies should use longer stimulation durations and image at various time points after stimulation cessation when exploring the effects of tDCS on cerebral blood flow (CBF).

Tolerability and Blinding of Transcranial Direct Current Stimulation in People with Parkinson's Disease: A Critical Review

Transcranial direct current stimulation (tDCS) is accompanied by transient sensations (e.g., tingling, itching, burning), which may affect treatment outcomes or break the blinding of the study protocol. Assessing tolerability and blinding is integral to providing ample evidence of a "real effect" from the applied stimulation and dispelling the possibility of placebo effects. People with Parkinson's disease (PwPD) endure many motor and non-motor symptoms that might be amenable to tDCS. However, because the disease also affects sensation capabilities, these subjects might report tolerability and blinding differently than other cohorts. Therefore, the purpose of this review was to aggregate the tolerability and blinding reports of tDCS studies in PwPD and recommend a standard tolerability and blinding reporting practice. A literature search of the PubMed and Scopus databases from 1 January 2020 to 1 April 2020 was performed to identify publications that applied tDCS to PwPD. Seventy studies were potentially reviewable, but only 36 (nine with quantitative tolerability reports, 20 with qualitative tolerability reports, and seven that only reported blinding) provided sufficient information to be included in the review. Quantitative information on tDCS tolerability and blinding maintenance in PwPD is scarce, and future reviews and metanalyses should carefully consider the possibility of placebo effects in their included studies.

No Immediate Effects of Transcranial Direct Current Stimulation at Various Intensities on Cerebral Blood Flow in People with Multiple Sclerosis

Animal and transcranial magnetic stimulation motors have evoked potential studies suggesting that the currently used transcranial direct current stimulation (tDCS) intensities produce measurable physiological changes. However, the validity, mechanisms, and general efficacy of this stimulation modality are currently being scrutinized. The purpose of this pilot study was to investigate the effects of dorsolateral prefrontal cortex tDCS on cerebral blood flow. A sample of three people with multiple sclerosis underwent two blocks of five randomly assigned tDCS intensities (1, 2, 3, 4 mA, and sham; 5 min each) and [¹⁵O]water positron emission tomography imaging. The relative regional (i.e., areas under the electrodes) and global cerebral blood flow were calculated. The results revealed no notable differences in regional or global cerebral blood flow from the different tDCS intensities. Thus, 5 min of tDCS at 1, 2, 3, and 4 mA did not result in immediate changes in cerebral blood flow. To achieve sufficient magnitudes of intracranial electrical fields without direct peripheral side effects, novel methods may be required.

"How to conquer a mountain with multiple sclerosis". How a climbing expedition to Machu Picchu affects the way people with multiple sclerosis experience their body and identity: a phenomenological analysis

BACKGROUND

People with multiple sclerosis (MS) frequently complain of chronic or fluctuating fatigue, sometimes accompanied by pain. From a phenomenological point of view, both fatigue and pain are seen as aspects of suffering which adversely affect the physical, psychological, social and even existential dimensions of the individual life.

OBJECTIVE

The present study discusses changes in identity and body awareness in people with MS who completed a 5-d trekking to Machu Picchu in Peru in 2012, after having completed a physical training schedule for several months.

METHOD AND DESIGN

All nine participants took part in a focus group organized after the trip. The Interpretative Phenomenological Analysis (IPA) was used to gain insight in their experiences and to refine pre-existing theoretical understanding of body awareness and identity.

RESULTS

Our phenomenological analysis clarified how aspects of the participants' identity and body experience before, during and after the journey influenced major daily themes as "body", "lived body", "behaviour" and "relationship" and how this contributed to a meaningful experience. When participants describe how they started looking at their own identity more consciously after being watched through the others' eyes, this resulted in a joyful transcending of their bodily power and endurance. In general, our data suggest that the more extreme, positive lived body experiences during the expedition were necessary for optimizing daily "routine" functioning.

CONCLUSION

Participating in Machu Picchu expedition appeared to have a deep and profound effect on body awareness and identity. Participants experienced their body once again as theirs, owning it and above all, allowing it to be a source of strength, joy and meaningfulness. While MS determined their lives prior to the journey, they now could look at MS as a part of what they are, without totally being absorbed in it. So being a patient with MS before, resulted in merely having MS after the climb. Implications for Rehabilitation Patients experience illness as a disruption of their previous life. A phenomenological approach deals with the lived experience and the concept of body awareness, the meaningful experience of living in the world through the body. This approach complements biomedical viewpoints as providing different. Suffering from a chronic and unpredictable disease like multiple sclerosis (MS) can disturb the implicit and harmonious relation between the body, the mind and the world, already at an early stage. Factors including physical training, professional guidance, social support, becoming a role model and completing a unique expedition outside of national and natural comfort borders may contribute to changes in body and identity experience.

Painful and involuntary multiple sclerosis

INTRODUCTION

Pain, dysphagia, respiratory problems, sexual and cardiovascular dysfunctions may occur in patients with MS.

AREAS COVERED

In the present review, we attempt to summarize the current knowledge on the impact pain, dysphagia, respiratory problems, sexual and cardiovascular dysfunctions have in patients with MS.

EXPERT OPINION

To effectively manage MS, it is essential that these symptoms are recognized as early as possible and treated by a rehabilitative multidisciplinary approach, based on proven scientific evidence.

Multiple sclerosis-related central pain disorders

Central neuropathic pain is common in multiple sclerosis (MS), and its prevalence increases with physical disability. Sufficient evidence links dysesthetic pain, trigeminal neuralgia, Lhermitte's sign, and painful tonics spasms to plaque formation in the spinal cord and brain, whereas the association with headache and back pain remains unclear. Management varies according to the pain in question. For dysesthetic pain, drugs in use for neuropathic pain in general are recommended as first-line treatment, and emerging evidence suggests some benefit from cannabinoids and levetiracetam. Because of unique characteristics of MS-related trigeminal neuralgia, ganglion and root level neuroablative procedures are worth considering before microvascular decompression. Overall, the lack of controlled clinical trials, together with our limited understanding of the pathophysiological mechanisms involved, form a hindrance to a systematic and rational management of MS-related pain.

The symptomatic management of multiple sclerosis

The management of multiple sclerosis (MS) revolves around disease management, symptom management, and person management. Of these, symptom management takes up the bulk of the time of the practicing physician. Some symptoms are easily managed whereas others are more difficult. Decisions have often to be made on whether to treat or to wait and watch. This article discusses the varied symptoms of MS and the approaches to management, which involves rehabilitation, pharmacological treatments, and surgical procedures. The skilled physician managing MS should be familiar with the multiple approaches to improving the quality of life of those with MS. After the diagnosis has been established and the decisions regarding treatment approaches have been made, the talk in a typical office appointment for MS usually turns to symptom management. Thus, the majority of management decisions made by the clinician revolve around that important topic. It is symptom management that will determine quality of life for those with MS, It is the basis for improving function, and, up until twenty years ago, it was the only basis for treating MS. Now, however, we can approach treatment by disease management, symptom management, and person management. The MS specialist must be well versed in all three areas.

Hypothalamic stimulation for trigeminal neuralgia in multiple sclerosis patients: efficacy on the paroxysmal ophthalmic pain

Trigeminal neuralgia is a disorder characterized by paroxysmal pain arising in one or more trigeminal branches; it is commonly reported in multiple sclerosis. In multiple sclerosis patients the ophthalmic branch may be frequently involved and the risks carried by neurosurgical ablative procedures are higher including major adverse effects such as corneal reflex impairment and keratitis. The objective of this works is to assess the role of posterior hypothalamus neuromodulation in the treatment of trigeminal neuralgia in multiple sclerosis patients. Five multiple sclerosis patients suffering from refractory recurrent trigeminal neuralgia involving all three trigeminal branches underwent deep brain stimulation of the posterior hypothalamus. The rationale of this intervention emerges from our earlier success in treating pain patients suffering from trigeminal autonomic cephalalgias. After follow-up periods that ranged from 1 to 4 years after treatment, the paroxysmal pain arising from the first trigeminal branch was controlled, whereas the recurrence of pain in the second and third trigeminal branches necessitated repeated thermorhizotomies to control in pain in two patients after 2 years of follow-up. In conclusion, deep brain stimulation may be considered as an adjunctive procedure for treating refractory paroxysmal pain within the first trigeminal division so as to avoid the complication of corneal reflex impairment that is known to follow ablative procedures.

Managing neuropathic pain with Sativex: a review of its pros and cons

BACKGROUND

Although not new, the use of cannabis-based drugs for treating chronic pain patients is becoming a hot topic for pain physicians and other specialists due to the constant flow of medical information regarding this pharmacological therapy. Its indication is becoming more clearly targeted towards pain syndromes arising from nerve damage. The number of cases reported, clinical trials and reviews published on this subject exponentially increase year by year. A possible explanation for this may be the fact that neuropathic pain is a highly disabling symptom and, consequently, there is a demand from patients and health professionals for a definitive remedy to treat this pain.

METHODS

Parallel to the number of articles on the effectiveness, recent articles describing the tolerability of cannabis-based drugs along with a more accurate characterisation of its side-effect profile and/or lack of effectiveness have been published, and they are placing a cautious stop for a more precise prescription of these medications.

CONCLUSION

This article reviews the current knowledge on the use of Sativex for treating neuropathic pains of different origin, and analyses the balance between the advantages and drawbacks of this therapy.