James Howells
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View article: Central and peripheral excitability in restless limbs syndrome
Central and peripheral excitability in restless limbs syndrome Open
Restless Limbs Syndrome (RLS) is a neurological disorder characterized by an uncontrollable urge to move the limbs. Although it affects up to 10% of the general population, its underlying mechanisms remain poorly understood. Neurophysiolog…
View article: Muscle excitability testing: Age and sex dependency of normative data
Muscle excitability testing: Age and sex dependency of normative data Open
Our results suggest that future studies no longer need to control for sex when using a healthy control group.
View article: Long‐term effects of widespread pharmaceutical pollution on trade‐offs between behavioural, life‐history and reproductive traits in fish
Long‐term effects of widespread pharmaceutical pollution on trade‐offs between behavioural, life‐history and reproductive traits in fish Open
In our rapidly changing world, understanding how species respond to shifting conditions is of paramount importance. Pharmaceutical pollutants are widespread in aquatic ecosystems globally, yet their impacts on animal behaviour, life‐histor…
View article: Threshold tracking transcranial magnetic stimulation and neurofilament light chain as diagnostic aids in <scp>ALS</scp>
Threshold tracking transcranial magnetic stimulation and neurofilament light chain as diagnostic aids in <span>ALS</span> Open
Objective There is a need for sensitive biomarkers in amyotrophic lateral sclerosis (ALS), to enable earlier diagnosis and to help assess potential treatments. The main objective of this study was to compare two potential biomarkers, thres…
View article: Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter
Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter Open
This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including ne…
View article: Short interval intracortical inhibition: Variability of amplitude and threshold-tracking measurements with 6 or 10 stimuli per point
Short interval intracortical inhibition: Variability of amplitude and threshold-tracking measurements with 6 or 10 stimuli per point Open
Reduced short-interval intracortical inhibition (SICI) in motor neuron disease has been demonstrated by amplitude changes (A-SICI) and threshold-tracking (T-SICI) using 10 stimuli per inter-stimulus interval (ISI). To test whether fewer st…
View article: Conventional and Threshold-Tracking Transcranial Magnetic Stimulation Tests for Single-handed Operation
Conventional and Threshold-Tracking Transcranial Magnetic Stimulation Tests for Single-handed Operation Open
Most single-pulse transcranial magnetic stimulation (TMS) parameters (e.g., motor threshold, stimulus-response function, cortical silent period) are used to examine corticospinal excitability. Paired-pulse TMS paradigms (e.g., short- and l…
View article: Early diagnosis of amyotrophic lateral sclerosis by threshold tracking and conventional transcranial magnetic stimulation
Early diagnosis of amyotrophic lateral sclerosis by threshold tracking and conventional transcranial magnetic stimulation Open
Background and purpose Short‐interval intracortical inhibition by threshold tracking (T‐SICI) has been proposed as a diagnostic tool for amyotrophic lateral sclerosis (ALS) but has not been compared directly with conventional amplitude mea…
View article: Motor unit changes in children with symptomatic spinal muscular atrophy treated with nusinersen
Motor unit changes in children with symptomatic spinal muscular atrophy treated with nusinersen Open
Objectives To elucidate the motor unit response to intrathecal nusinersen in children with symptomatic spinal muscular atrophy (SMA) using a novel motor unit number estimation technique. Methods MScanFit MUNE studies were sequentially unde…
View article: Cortical inexcitability defines an adverse clinical profile in amyotrophic lateral sclerosis
Cortical inexcitability defines an adverse clinical profile in amyotrophic lateral sclerosis Open
Background and purpose In amyotrophic lateral sclerosis, studies using threshold‐tracking transcranial magnetic stimulation (TMS) have identified corticomotoneuronal dysfunction as a key pathogenic mechanism. Some patients, however, displa…
View article: Acute changes in nerve excitability following oxaliplatin treatment in mice
Acute changes in nerve excitability following oxaliplatin treatment in mice Open
We present a novel mouse model of acute oxaliplatin-induced peripheral neurotoxicity that is comparable to clinical observations. Intramuscular injection of oxaliplatin produced acute changes in motor nerve excitability that were attributa…
View article: 018 Role of transcallosal inhibition in disease spread in ALS
018 Role of transcallosal inhibition in disease spread in ALS Open
Introduction There is substantial evidence for the cortical origin of amyotrophic lateral sclerosis (ALS). Impaired function of the corpus callosum has been demonstrated in ALS patients and may play a role in disease spread, potentially me…
View article: 009 Axonal excitability properties in dravet’s syndrome reflect effect of loss of sodium channels
009 Axonal excitability properties in dravet’s syndrome reflect effect of loss of sodium channels Open
Introduction Mutations in SCN1A encoding the Na v 1.1 subunit of the neuronal sodium channel underlie the devastating epilepsy of Dravet’s syndrome. 1 The mechanism by which Na v 1.1 dysfunction causes seizures is not clear. In vitro and i…
View article: <i>I</i><sub>h</sub> contributes to increased motoneuron excitability in restless legs syndrome
<i>I</i><sub>h</sub> contributes to increased motoneuron excitability in restless legs syndrome Open
Key points Restless legs patients complain about sensory and motor symptoms leading to sleep disturbances. Symptoms include painful sensations, an urge to move and involuntary leg movements. The responsible mechanisms of restless legs synd…
View article: <i>In vivo</i> evidence for reduced ion channel expression in motor axons of patients with amyotrophic lateral sclerosis
<i>In vivo</i> evidence for reduced ion channel expression in motor axons of patients with amyotrophic lateral sclerosis Open
Key points The progressive loss of motor units in amyotrophic lateral sclerosis (ALS) is initially compensated for by the reinnervation of denervated muscle fibres by surviving motor axons. A disruption in protein homeostasis is thought to…
View article: Physiological Processes Underlying Short Interval Intracortical Facilitation in the Human Motor Cortex
Physiological Processes Underlying Short Interval Intracortical Facilitation in the Human Motor Cortex Open
Short interval intracortical facilitation (SICF) may be elicited by a paired pulse transcranial magnetic stimulation (TMS) paradigm, whereby a suprathreshold first stimulus (S1) precedes a perithreshold second stimulus (S2). Other facilita…
View article: Diuretic‐sensitive electroneutral Na<sup>+</sup> movement and temperature effects on central axons
Diuretic‐sensitive electroneutral Na<sup>+</sup> movement and temperature effects on central axons Open
Key points Optic nerve axons get less excitable with warming. F‐fibre latency does not shorten at temperatures above 30°C. Action potential amplitude falls when the Na + ‐pump is blocked, an effect speeded by warming. Diuretics reduce the …
View article: Burning pain: axonal dysfunction in erythromelalgia
Burning pain: axonal dysfunction in erythromelalgia Open
Erythromelalgia (EM) is a rare neurovascular disorder characterized by intermittent severe burning pain, erythema, and warmth in the extremities on heat stimuli. To investigate the underlying pathophysiology, peripheral axonal excitability…
View article: Differentiating lower motor neuron syndromes
Differentiating lower motor neuron syndromes Open
Lower motor neuron (LMN) syndromes typically present with muscle wasting and weakness and may arise from pathology affecting the distal motor nerve up to the level of the anterior horn cell. A variety of hereditary causes are recognised, i…
View article: Accommodation to hyperpolarization of human axons assessed in the frequency domain
Accommodation to hyperpolarization of human axons assessed in the frequency domain Open
Human axons in vivo were subjected to subthreshold currents with a threshold impedance amplitude profile to allow the use of frequency domain techniques to determine the propensity for resonant behavior and to clarify the relative contribu…
View article: Cortical Function in Asymptomatic Carriers and Patients With<i>C9orf72</i>Amyotrophic Lateral Sclerosis
Cortical Function in Asymptomatic Carriers and Patients With<i>C9orf72</i>Amyotrophic Lateral Sclerosis Open
This study establishes cortical hyperexcitability as an intrinsic feature of symptomatic c9orf72 expansion-related ALS but not asymptomatic expansion carriers.
View article: Increased HCN channel driven inward rectification in benign cramp fasciculation syndrome
Increased HCN channel driven inward rectification in benign cramp fasciculation syndrome Open
Muscle cramps are a common complaint associated with sudden painful involuntary contractions of a muscle. The mechanisms responsible for muscle cramps are still not clear. Axonal excitability and multi-unit electromyography studies were pe…