TMS for ALS: why and why not

Brain-derived neurotrophic factor/tropomyosin receptor kinase B signaling in spinal muscular atrophy and amyotrophic lateral sclerosis

Tropomyosin receptor kinase B (TrkB) and its primary ligand brain-derived neurotrophic factor (BDNF) are expressed in the neuromuscular system, where they affect neuronal survival, differentiation, and functions. Changes in BDNF levels and full-length TrkB (TrkB-FL) signaling have been revealed in spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), two common forms of motor neuron diseases that are characterized by defective neuromuscular junctions in early disease stages and subsequently progressive muscle weakness. This review summarizes the current understanding of BDNF/TrkB-FL-related research in SMA and ALS, with an emphasis on their alterations in the neuromuscular system and possible BDNF/TrkB-FL-targeting therapeutic strategies. The limitations of current studies and future directions are also discussed, giving the hope of discovering novel and effective treatments.

Assessing the upper motor neuron in amyotrophic lateral sclerosis using the triple stimulation technique: A multicenter prospective study

OBJECTIVE

To evaluate the relevance of transcranial magnetic stimulation (TMS) using triple stimulation technique (TST) to assess corticospinal function in amyotrophic lateral sclerosis (ALS) in a large-scale multicenter study.

METHODS

Six ALS centers performed TST and conventional TMS in upper limbs in 98 ALS patients during their first visit to the center. Clinical evaluation of patients included the revised ALS Functional Rating Scale (ALSFRS-R) and upper motor neuron (UMN) score.

RESULTS

TST amplitude ratio was decreased in 62% of patients whereas conventional TMS amplitude ratio was decreased in 25% of patients and central motor conduction time was increased in 16% of patients. TST amplitude ratio was correlated with ALSFRS-R and UMN score. TST amplitude ratio results were not different between the centers.

CONCLUSIONS

TST is a TMS technique applicable in daily clinical practice in ALS centers for the detection of UMN dysfunction, more sensitive than conventional TMS and related to the clinical condition of the patients.

SIGNIFICANCE

This multicenter study shows that TST can be a routine clinical tool to evaluate UMN dysfunction at the diagnostic assessment of ALS patients.

Remotely supervised transcranial direct current stimulation: A feasibility study for amyotrophic lateral sclerosis

BACKGROUND

Transcranial direct current stimulation (tDCS) has been investigated as a therapeutic neuromodulation tool in several neurological disorders. However, evidence supporting its efficacy in disorders such as amyotrophic lateral sclerosis (ALS) is limited possibly due to limited patient accessibility for research, particularly for individuals with advanced disease progression. Telerehabilitation using home-based protocols allows for remote supervision of tDCS over longer durations, thereby increasing participation, compliance and adherence. In this study, we explored the safety, feasibility and preliminary effects of a remotely supervised tDCS (RS-tDCS) protocol in ALS.

MATERIAL AND METHODS

In this pre-post case series study, two individuals with ALS completed 24 remotely supervised anodal tDCS sessions (20 minutes, 2 mA). Outcomes included adherence, compliance, disease progression, walking speed, risk of fall, endurance, fatigue and depression.

RESULTS

Both participants successfully completed the study without any major adverse effects. Minor side effects included mild sensations of itching and throbbing under the electrodes during stimulation. Clinical outcomes showed minimal to no change for any of the measures.

CONCLUSIONS

Preliminary findings suggest that the RS-tDCS protocol is safe and feasible in individuals with ALS. Our protocol serves as a model for future long-term studies to evaluate the clinical and neurophysiological effects of tDCS using a telerehabilitation protocol in ALS.

Symptomatic treatments for amyotrophic lateral sclerosis/motor neuron disease

BACKGROUND

Motor neuron disease (MND), which is also known as amyotrophic lateral sclerosis (ALS), causes a wide range of symptoms but the evidence base for the effectiveness of the symptomatic treatment therapies is limited.

OBJECTIVES

To summarise the evidence from Cochrane Systematic Reviews of all symptomatic treatments for MND.

METHODS

We searched the Cochrane Database of Systematic Reviews (CDSR) on 15 November 2016 for systematic reviews of symptomatic treatments for MND. We assessed the methodological quality of the included reviews using the Assessment of Multiple Systematic Reviews (AMSTAR) tool and the GRADE approach. We followed standard Cochrane study (review) selection and data extraction procedures. We reported findings narratively and in tables.

MAIN RESULTS

We included nine Cochrane Systematic Reviews of interventions to treat symptoms in people with MND. Three were empty reviews with no included randomised controlled trials (RCTs); however, all three reported on non-RCT evidence and the remaining six included mostly one or two studies. We deemed all of the included reviews of high methodological quality. Drug therapy for painThere is no RCT evidence in a Cochrane Systematic Review exploring the efficacy of drug therapy for pain in MND. Treatment for crampsThere is evidence (13 RCTs, N = 4012) that for the treatment of cramps in MND, compared to placebo:- memantine and tetrahydrocannabinol (THC) are probably ineffective (moderate-quality evidence);- vitamin E may have little or no effect (low-quality evidence); and- the effects of L-threonine, gabapentin, xaliproden, riluzole, and baclofen are uncertain as the evidence is either very low quality or the trial specified the outcome but did not report numerical data.The review reported adverse effects of riluzole, but it is not clear whether other interventions had adverse effects. Treatment for spasticityIt is uncertain whether an endurance-based exercise programme improved spasticity or quality of life, measured at three months after the programme, as the quality of evidence is very low (1 RCT, comparison "usual activities", N = 25). The review did not evaluate other approaches, such as use of baclofen as no RCTs were available. Mechanical ventilation for supporting respiratory functionNon-invasive ventilation (NIV) probably improves median survival and quality of life in people with respiratory insufficiency and normal to moderately impaired bulbar function compared to standard care, and improves quality of life but not survival for people with poor bulbar function (1 RCT, N = 41, moderate-quality evidence; a second RCT did not provide data). The review did not evaluate other approaches such as tracheostomy-assisted ('invasive') ventilation, or assess timing of NIV initiation. Treatment for sialorrhoeaA single session of botulinum toxin type B injections to parotid and submandibular glands probably improves sialorrhoea and quality of life at up to 4 weeks compared to placebo injections, but not at 8 or 12 weeks after the injections (moderate-quality evidence from 1 placebo-controlled RCT, N = 20). The review authors found no trials of other approaches. Enteral tube feeding for supporting nutritionThere is no RCT evidence in a Cochrane Systematic Review to support benefit or harms of enteral tube feeding in supporting nutrition in MND. Repetitive transcranial magnetic stimulationIt is uncertain whether repetitive transcranial magnetic stimulation (rTMS) improves disability or limitation in activity in MND in comparison with sham rTMS (3 RCTs, very low quality evidence, N = 50). Therapeutic exerciseThere is evidence that exercise may improve disability in MND at three months after the exercise programme, but not quality of life, in comparison with "usual activities" or "usual care" including stretching (2 RCTs, low-quality evidence, N = 43). Multidisciplinary careThere is no RCT evidence in a Cochrane Systematic Review to demonstrate any benefit or harm for multidisciplinary care in MND.None of the reviews, other than the review of treatment for cramps, reported that adverse events occurred. However, the trials were too small for reliable adverse event reporting.

AUTHORS' CONCLUSIONS

This overview has highlighted the lack of robust evidence in Cochrane Systematic Reviews on interventions to manage symptoms resulting from MND. It is important to recognise that clinical trials may fail to demonstrate efficacy of an intervention for reasons other than a true lack of efficacy, for example because of insufficient statistical power, the wrong choice of dose, insensitive outcome measures or inappropriate participant eligibility. The trials were mostly too small to reliably assess adverse effects of the treatments. The nature of MND makes it difficult to research clinically accepted or recommended practice, regardless of the level of evidence supporting the practice. It would not be ethical, for example, to design a placebo-controlled trial for treatment of pain in MND or to withhold multidisciplinary care where such care is available. It is therefore highly unlikely that there will ever be classically designed placebo-controlled RCTs in these areas.We need more research with appropriate study designs, robust methodology, and of sufficient duration to address the changing needs-of people with MND and their caregivers-associated with MND disease progression and mortality. There is a significant gap in studies assessing the effectiveness of interventions for symptoms relating to MND, such as pseudobulbar emotional lability and cognitive and behavioural difficulties. Future studies should use appropriate outcome measures that are reliable, have internal and external validity, and are sensitive to change in what is being measured (such as quality of life).

Repetitive transcranial magnetic stimulation for the treatment of amyotrophic lateral sclerosis or motor neuron disease

BACKGROUND

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND), is a progressive neurodegenerative disease without effective therapies. Several studies have suggested that repetitive transcranial magnetic stimulation (rTMS) may have positive benefit in ALS. However, the efficacy and safety of this therapy remain uncertain. This is the first update of a review published in 2011.

OBJECTIVES

To determine the clinical efficacy and safety of rTMS for treating ALS.

SEARCH METHODS

On 30 July 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, issue 7 in The Cochrane Library), MEDLINE (1966 to July 2012), EMBASE (1980 to July 2012), CINAHL (1937 to July 2012), Science Citation Index Expanded (January 1945 to July 2012), AMED (January 1985 to July 2012). We searched the Chinese Biomedical Database (1979 to August 2012). We also searched for ongoing studies on clinicaltrials.gov (August 2012).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials assessing the therapeutic efficacy and safety of rTMS for patients with a clinical diagnosis of ALS.Comparisons eligible for inclusion were:1. rTMS versus no intervention;2. rTMS versus sham rTMS;3. rTMS versus physiotherapy;4. rTMS versus medications;5. rTMS + other therapies or drugs versus sham rTMS + the same therapies or drugs;6. different methods of application of rTMS such as high-frequency (> 1Hz) compared to low-frequency (≤ 1Hz) rTMS.

DATA COLLECTION AND ANALYSIS

Two authors independently selected papers, assessed risk of bias and extracted data. We resolved disagreements through discussion. We contacted study authors for additional information.

MAIN RESULTS

Three randomised, placebo-controlled trials with a total of 50 participants were included in the review. All three trials compared rTMS with sham TMS. All the trials were of poor methodological quality and were insufficiently homogeneous to allow the pooling of results. Moreover, the high rate of attrition further increased the risk of bias. None of the trials provided detailed data on the ALS Functional Rating Scale-Revised (ALSFRS-R) scores at six months follow-up which was pre-assigned as our primary outcome. One trial contained data in a suitable form for quantitative analysis of our secondary outcomes. No difference was seen between rTMS and sham rTMS using the ALSFRS-R scores and manual muscle testing (MMT) scores at 12 months follow-up in this trial. Additionally, none of the trials reported any adverse events associated with the use of rTMS. However, in view of the small sample size, the methodological limitations and incomplete outcome data, treatment with rTMS cannot be judged as completely safe.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to draw conclusions about the efficacy and safety of rTMS in the treatment of ALS. Further studies may be helpful if their potential benefit is weighed against the impact of participation in a randomised controlled trial on people with ALS.

Rapidly progressive amyotrophic lateral sclerosis initially masquerading as a demyelinating neuropathy

Rare cases of demyelinating neuropathy have been described in association with amyotrophic lateral sclerosis (ALS). We report two patients with typical ALS whose initial electroneuromyographic (ENMG) presentation could suggest the existence of a process of motor nerve fiber demyelination. However, subsequent ENMG examinations and the fatal course of the disease in a few months rather supported severe ongoing axonal degeneration at the origin of motor nerve conduction abnormalities. Repeated examinations could be required to distinguish between ENMG features of concomitant demyelinating neuropathy and rapidly progressive motor neuron loss in ALS.

Spinal cord markers in ALS: diagnostic and biomarker considerations

Despite considerable involvement of the spinal cord in amyotrophic lateral sclerosis (ALS), current biomarker research is primarily centred on brain imaging and CSF proteomics. In clinical practice, spinal cord imaging in ALS is performed primarily to rule out alternative conditions in the diagnostic phase of the disease. Quantitative spinal cord imaging has traditionally been regarded as challenging, as it requires high spatial resolution while minimizing partial volume effects, physiological motion and susceptibility distortions. In recent years however, as acquisition and post-processing methods have been perfected, a number of exciting and promising quantitative spinal imaging and electrophysiology techniques have been developed. We performed a systematic review of the trends, methodologies, limitations and conclusions of recent spinal cord studies in ALS to explore the diagnostic and prognostic potential of spinal markers. Novel corrective techniques for quantitative spinal cord imaging are systematically reviewed. Recent findings demonstrate that imaging techniques previously used in brain imaging, such as diffusion tensor, functional and metabolic imaging can now be successfully applied to the human spinal cord. Optimized electrophysiological approaches make the non-invasive assessment of corticospinal pathways possible, and multimodal spinal techniques are likely to increase the specificity and sensitivity of proposed spinal markers. In conclusion, spinal cord imaging is an emerging area of ALS biomarker research. Novel quantitative spinal modalities have already been successfully used in ALS animal models and have the potential for development into sensitive ALS biomarkers in humans.

Repetitive transcranial magnetic stimulation for the treatment of amyotrophic lateral sclerosis or motor neuron disease

BACKGROUND

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND), is a progressive neurodegenerative disease without effective therapies. Several studies have suggested that repetitive transcranial magnetic stimulation (rTMS) may have positive benefit in ALS. However, the efficacy and safety of this therapy remain uncertain.

OBJECTIVES

We aimed to determine the clinical efficacy and safety of rTMS for treating ALS.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialized Register (July 2010), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2010), MEDLINE (1966 to July 2010), EMBASE (1980 to July 2010), CINAHL (1937 to July 2010), Science Citation Index Expanded (January 1945 to June 2010), AMED (January 1985 to July 2010) and the Chinese Biomedical Database (1979 to September 2010). We also searched for ongoing studies on clinicaltrials.gov (September 2010).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials assessing the therapeutic efficacy and safety of rTMS for patients with a clinical diagnosis of ALS.Comparisons eligible for inclusion were:1. rTMS versus no intervention;2. rTMS versus sham rTMS;3. rTMS versus physiotherapy;4. rTMS versus medications;5. rTMS + other therapies or drugs versus sham rTMS + the same therapies or drugs;6. different methods of application of rTMS such as high-frequency (> 1Hz) compared to low-frequency (≤ 1Hz) rTMS.

DATA COLLECTION AND ANALYSIS

Two authors independently selected papers, assessed risk of bias and extracted data. We resolved disagreements through discussion. We contacted study authors for additional information.

MAIN RESULTS

Three randomised, placebo-controlled trials with a total of 50 participants were included in the review. All the trials were of poor methodological quality and were insufficiently homogeneous to allow the pooling of results. Moreover, the high rate of attrition further increased the risk of bias. None of the trials provided detailed data on the ALS Functional Rating Scale-Revised (ALSFRS-R) scores at six months follow-up which was pre-assigned as our primary outcome. One trial contained data in a suitable form for quantitative analysis of our secondary outcomes. No difference was seen between rTMS and sham rTMS using the ALSFRS-R scores and manual muscle testing (MMT) scores at 12 months follow-up in this trial. Additionally, none of the trials reported any adverse events associated with the use of rTMS. However, in view of the small sample size, the methodological limitations and incomplete outcome data, treatment with rTMS cannot be judged as completely safe.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to draw conclusions about the efficacy and safety of rTMS in the treatment of ALS. Further studies may be helpful if their potential benefit is weighed against the impact of participation in a randomised controlled trial on people with ALS.

Long-term motor cortex stimulation for amyotrophic lateral sclerosis

BACKGROUND

Motor cortex stimulation has been proposed for treatment of amyotrophic lateral sclerosis (ALS) and preliminary studies have reported a slight reduction of disease progression using both invasive and noninvasive repetitive stimulation of the motor cortex.

OBJECTIVE

The aim of this proof of principle study was to investigate the effects of motor cortex stimulation performed for a prolonged period (about 2 years) on ALS progression.

METHODS

Two patients were included in the study; the first patient was treated with monthly cycles of repetitive transcranial magnetic stimulation (rTMS) and the second one was treated with chronic epidural motor cortex stimulation. The rate of progression of the disease before and during treatment was compared.

RESULTS

The treatments were well tolerated by the patients. Both patients deteriorated during treatment; however, the patient treated with rTMS showed a slight reduction in deterioration rate.

CONCLUSIONS

Although we cannot be sure whether the effects observed in the patient treated with rTMS can be attributed to this form of stimulation, our study set the groundwork for possible future studies investigating the effects of rTMS, for a prolonged period, on a larger group of ALS patients.

Electrodiagnostic criteria for diagnosis of ALS

A consensus meeting was held to determine the best use and interpretation of electrophysiological data in the diagnosis of ALS. The utility of needle EMG and nerve conduction studies was affirmed. It is recommended that electrophysiological evidence for chronic neurogenic change should be taken as equivalent to clinical information in the recognition of involvement of individual muscles in a limb. In addition, in the context of a suspected clinical diagnosis of ALS, fasciculation potentials should be taken as equivalent to fibrillation potentials and positive sharp waves in recognising denervation. The importance of searching for instability in fasciculation potentials and in motor unit potentials in ALS is stressed. These changes in the interpretation of electrophysiological data render obsolete the category Probable Laboratory-Supported ALS in the modified El Escorial diagnostic criteria for ALS. Methods for detection of upper motor neuron abnormality appear sensitive but require further study, particularly regarding their value when clinical signs of upper motor neuron lesion are uncertain.

Repetitive transcranial magnetic stimulation for ALS

Repetitive transcranial magnetic stimulation (rTMS) of brain can modulate cortical neurotransmission, a novel paradigm of repetitive stimulation termed continuous theta-burst stimulation (cTBS) produces a pronounced and prolonged suppression of motor cortex excitability. The aim of this preliminary study was to investigate whether cTBS of motor cortex could have any beneficial effect in patients with amyotrophic lateral sclerosis (ALS). We performed a double-blind, placebo-controlled trial. Twenty patients with definite ALS were randomly allocated to blinded active or placebo stimulation. Repetitive stimulation of the motor cortex was performed for five consecutive days every month for six consecutive months. The primary outcome was the rate of decline as evaluated with the ALS functional rating scale. The treatment was well tolerated by the patients. Fifteen patients (seven active and eight sham) completed the study and were included in the 6-months analysis. Both active and sham patients deteriorated during treatment, however, active patients showed a modest but significant slowing of the deterioration rate. Though we cannot be sure whether the effects observed can be attributed to cTBS, because of the restricted number of patients studied, further investigation on a larger group of ALS patients is warranted. The results of the pilot study might open up a new therapeutic perspective in ALS based on neuromodulation.

Chronic Cortical Stimulation for Amyotropic Lateral Sclerosis: A Report of Four Consecutive Operated Cases after a 2-Year Follow-up: Technical Case Report

OBJECTIVE AND IMPORTANCE

From April to July 2002, four consecutive patients affected by amyotrophic lateral sclerosis (ALS) were surgically treated with bilateral chronic cortical stimulation..

CLINICAL PRESENTATION

The preoperative diagnostic assessment was based on the results of a neurological examination, integrated by the ALS functional rating scale, electromyography, magnetic resonance imaging, and single-photon emission computed tomography (SPECT). In particular, SPECT provided a remarkable contribution in terms of its ability to demonstrate specific morphological and metabolic ALS lesions of the brain.

INTERVENTION

The postoperative neurological follow-up was based mainly on the assessment of neurological status and the ALS functional rating scale, together with SPECT. Two years after surgery, at clinical examination, two patients demonstrated mild progression of their illness, and SPECT findings disclosed complete disappearance of ALS cerebral lesions, with apparent recovery of brain anatomic integrity. The third patient committed suicide. In the fourth patient, the disease seemed to have progressed inexorably at the time of clinical and SPECT monitoring, after transient improvement during the first 3 months after surgery..

CONCLUSION

These preliminary results are surprising, because they suggest that chronic cortical stimulation can play a role against ALS and deserve confirmation in larger numbers of patients and for a longer follow-up. We present the theoretical grounds for these findings, as well as the diagnostic and surgical procedures and results..