PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain myalgia , trouble remaining upright orthostatic intolerance , sleep abnormalities, and gastro-intestinal impairments, among others. The information provided at this site is not intended to diagnose or treat any illness. Jump to: navigation , search. Muscle fasciculations in potassium channelopathy by vlivings. It has been postulated that the IFI of these doublets can indicate the origin of the doublet, owing to varying characteristics of the recovery cycle at different locations along the motor neuron.
Faced with the low occurrence rate of doublets during electrical stimulation Maathuis et al. In turn, this might help to elucidate the origin of fasciculations in amyotrophic lateral sclerosis. In this study, we set out to calibrate our novel analytical system longitudinally in the clinical context of amyotrophic lateral sclerosis disease progression. We have compared these results with control subjects who have benign fasciculation syndrome, a condition that is defined by the isolated presence of fasciculations, particularly in muscles of the lower limbs, without evidence of underlying motor neuron degeneration Blexrud et al.
We aimed to identify a novel quantitative biomarker related to fasciculations that could monitor patients with amyotrophic lateral sclerosis over time. If this could be achieved, the relative simplicity of the HDSEMG technique, working alongside an automated analytical system, would make its widespread application as a clinical and research tool more viable. Twenty patients with amyotrophic lateral sclerosis and five patients with benign fasciculation syndrome each underwent up to seven assessments at intervals of 2 months Table 1.
Patients with amyotrophic lateral sclerosis were diagnosed with probable or definite amyotrophic lateral sclerosis using the revised El Escorial Criteria Brooks et al. One patient with benign fasciculation syndrome withdrew early due to relocation away from London. Data from a further eight patients six patients with amyotrophic lateral sclerosis, one with benign fasciculation syndrome and one with multifocal motor neuropathy from our previously reported pilot study Bashford et al.
Muscle powers were assessed at baseline by the same clinician J. Baseline demographic data and a neurological examination were documented on the first visit. Patients were asked to report the month of onset of their symptoms defined as the first occurrence of persistent weakness in a typical muscle group for patients with amyotrophic lateral sclerosis. As clinical measures of disease progression in patients with amyotrophic lateral sclerosis, we performed the amyotrophic lateral sclerosis-functional rating scale Cedarbaum et al.
In brief, an initial screen for MU potentials was applied to each recording channel. This involved the detection of the most extreme amplitudes positive and negative , representing the peaks and troughs of MU potentials. Based on manual counts, we found a linear relationship between average noise levels and the optimal amplitude inclusion threshold for fasciculation potentials. In addition, areas of the recording with excessive noise were automatically identified and excluded from further analysis.
Unrelaxed muscle activity was identified by Active Voluntary IDentification, a semi-automated, flexible system built to exclude regular trains of MU potentials Bashford et al. As a parallel neurophysiological measure, we performed the motor unit number index MUNIX in three muscles bilaterally abductor pollicis brevis, biceps brachii and extensor digitorum brevis for patients with amyotrophic lateral sclerosis and benign fasciculation syndrome Nandedkar et al.
Statistical tests were performed in Prism V7. Laptops with Intel i7 2. Inverted scores for power were reverted back to the correct scale. To calculate a P -value, a comparison model was created, which omitted the fixed effect in question. An analysis of variance test was performed comparing the addition of the fixed effect, which produced a P -value according to the chi-squared test.
An additional benefit of using mixed-effect models was that missing values did not invalidate the model. We assigned each muscle in the study to one of the following three groups:. This still allowed us to assess the chronology of changes, albeit in a less rigorous way than a continuous time scale. The supporting data for this study are available from the corresponding author upon reasonable request. A total of biceps, gastrocnemius amyotrophic lateral sclerosis and 58 biceps, 58 gastrocnemius benign fasciculation syndrome recordings were analysed.
Ten biceps recordings from two patients with amyotrophic lateral sclerosis were excluded due to contamination from a Parkinsonian resting tremor seven recordings from the right biceps of patient 3 or the electrocardiogram three recordings from the left biceps of patient There was no difference in noise band between patients with amyotrophic lateral sclerosis 2.
Biceps generated higher noise band values than gastrocnemius 3. There was no difference in the number of channels included between patients with amyotrophic lateral sclerosis There was also no difference in the total time included between patients with amyotrophic lateral sclerosis Only patients with amyotrophic lateral sclerosis had the amyotrophic lateral sclerosis-functional rating scale performed at each visit Fig.
The baseline was Change in clinical parameters over time. Only patients with amyotrophic lateral sclerosis had a sum MRC power score recorded at each visit Fig. Only patients with amyotrophic lateral sclerosis had a slow vital capacity recorded at each visit Fig. Four out of 20 patients either declined slow vital capacity testing or had significant facial weakness making the results unreliable.
Two out of 20 patients developed the need for non-invasive ventilation during the course of the study, and slow vital capacity testing was not continued. These rates of decline in patients with amyotrophic lateral sclerosis were comparable to a previous longitudinal study for these upper limb muscles Neuwirth et al. Moreover, among patients with amyotrophic lateral sclerosis, there was a significant decline in MUNIX-biceps in both strong muscles [—2.
Baseline MUNIX-extensor digitorum brevis was lower in patients with amyotrophic lateral sclerosis compared to patients with benign fasciculation syndrome Overall, MUNIX was reliable in all three muscles as a monitoring tool in patients with amyotrophic lateral sclerosis. We analysed biceps and gastrocnemius separately while obtaining comparisons between the two disease groups Fig.
For patients with amyotrophic lateral sclerosis, the FF baselines were For patients with benign fasciculation syndrome, the baselines were 4. Change in FF over time. A FF against months since symptom onset per muscle per patient group. Individual patients are colour coded see legend. Weak amyotrophic lateral sclerosis muscles are filled circles, and strong amyotrophic lateral sclerosis muscles are clear circles. The larger the symbol, the weaker the muscle at the time of recording.
Subsequently, we focused on the amyotrophic lateral sclerosis group. Having shown that both FF and sum muscle power scores decreased linearly over time, we expected a direct linear correlation between FF and individual muscle power scores.
This led us to suspect that a non-linear relationship might better describe the relationship between these two parameters in biceps. Interestingly, when the strong biceps muscles were removed from the model, there was a significant FF decline of — To examine this further, we tested whether the presence of muscle weakness in patients with amyotrophic lateral sclerosis influenced the change in FF over time. For strong gastrocnemius muscles in patients with amyotrophic lateral sclerosis observations from 29 muscles in 16 patients , the baseline FF was For weak gastrocnemius muscles in patients with amyotrophic lateral sclerosis 31 observations from 8 muscles in 6 patients , the baseline FF was These results are summarized in Fig.
Although benign fasciculation syndrome is not considered a prodrome of amyotrophic lateral sclerosis, our interpretation of these results relied on the assumption that the baseline FF in patients with benign fasciculation syndrome represented the amyotrophic lateral sclerosis baseline prior to disease onset.
This supported our suspicion that biceps FF was non-linear, first rising steadily from a pre-morbid baseline in strong muscles and subsequently falling as weakness ensued. In contrast to biceps, gastrocnemius demonstrated a significant decline in FF in strong muscles, which plateaued in weak muscles. Fasciculation amplitude was employed as an easily quantifiable surrogate of the reinnervation process. When we observed the amplitude histograms of individual min recordings, we noticed a particular pattern of multiple high-amplitude peaks in patients with amyotrophic lateral sclerosis but never in patients with benign fasciculation syndrome Fig.
We believe that these peaks represent the increased fasciculation rate of a subset of MUs rendered hyperexcitable by the disease process. We extracted the average amplitude value median and a measure of amplitude spread inter-quartile range from each recording to quantify this distinguishing feature. For biceps, the amplitude was higher in patients with amyotrophic lateral sclerosis However, for gastrocnemius, there was no difference between the two groups For amplitude spread, there was a trend for higher values in amyotrophic lateral sclerosis Similarly for gastrocnemius, there was no difference in amplitude spread between the two groups Comparison of amplitude parameters.
Representative amplitude histograms from individual min recordings from A biceps of a patient with amyotrophic lateral sclerosis and B gastrocnemius of a patient with benign fasciculation syndrome. C The average amplitude value median and amplitude spread IQR have been calculated for each min recording.
Boxes and whiskers display means and standard error. Post hoc multiple comparison testing was performed using Holm-Bonferroni correction in R. Next, we assessed whether fasciculation amplitude changed over time in patients with amyotrophic lateral sclerosis. For biceps, the baseline was For gastrocnemius, the baseline was The rise in baseline amplitudes between strong and weak muscles, particularly in biceps, warranted further exploration.
There were no differences between these three weakness groups and the benign fasciculation syndrome group in the gastrocnemius recordings. This suggested that the fasciculating MUs from the biceps of patients with amyotrophic lateral sclerosis had undergone varying degrees of reinnervation dependent on the stage of disease, whereas those from gastrocnemius had not.
Although the sheer number of analysed fasciculation potentials precluded confirmatory morphological analysis, these peaks are consistent with fasciculation doublets. Analysis of IFIs. These represent intervals between FPs arising from different MUs. FPs have been recorded from bilateral muscles of 26 patients with amyotrophic lateral sclerosis 1—7 assessments per patient , 6 patients with benign fasciculation syndrome 2—7 assessments per patient and 1 patient with multifocal motor neuropathy 6 assessments.
Note varying y -axis scales of insets. FP: fasciculation potential. If working with a counselor or kicking your smoking habit do not cure your twitches, seeing a neurologist may be the answer. There are many different conditions and disorders of the nervous system that can affect the distal nervous system, potentially causing twitches in the lower limbs. These include:. Other causes of neurologic abnormality can come about by incidents in your daily life. It is possible that physical trauma could cause damage to the spinal cord.
Other potential causes include rabies, which can be contracted from an encounter with an infected animal. Given the seriousness of amyotrophic lateral sclerosis, people naturally worry that any symptom of ALS could be the sign they have this very serious disease. While muscle fasciculations can be a symptom of ALS, there are other, more sure signs of disease progression to look for.
Muscular atrophy, or a generalized weakness, is a sign of ALS that is far more worrying. If you are concerned that your symptoms are the sign of something more serious, be sure to talk to a healthcare professional.
There are conclusive tests that can be performed to determine whether ALS is the cause of your twitching. You may find out you are experiencing a lifestyle-induced form of BFS caused by something like over-the-counter drugs, smoking, stress, or even too much strenuous exercise.
Where and how your twitches occur is also an indication of what may be going on. The fasciculations associated with BFS often occur in the eyelids known as myokymia or in your lower motor neurons. ALS can cause broader effects in your peripheral neuropathy, with twitching and muscle weakness occurring throughout the body. There are many conditions that can cause or contribute to fasciculations. Fasciculation potentials recorded from 63 muscles of 28 patients with definite amyotrophic lateral sclerosis were compared with those from 21 muscles of 11 patients with the benign fasciculation syndrome.
In each muscle, at a single site, up to 15 identifiable fasciculation potentials could be recognized. Thus the characteristics of fasciculations from patients with amyotrophic lateral sclerosis and benign fasciculations were analysed.
Fasciculation potential amplitude, area, turns, duration, firing interval, indices of waveform variability, evidence of axonal conduction block, evidence of axonal conduction variability and propensity to produce double fasciculations were measured.
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