A new parameter to discriminate amyotrophic lateral sclerosis patients from healthy participants by motor cortical excitability changes.

INTRODUCTION: We sought a combination of abnormalities to define a more sensitive measure of cortical excitability in amyotrophic lateral sclerosis (ALS). METHODS: The automatic threshold tracking method was employed to assess the resting motor threshold, intracortical facilitation (ICF), short-interval intracortical inhibition (SICI), and short-interval intracortical faciilitation (SICF) in patients and controls. RESULTS: SICF at interstimulus intervals (ISI) between 1 and 1.8 ms and 2 and 3 ms as well as average SICI and SICI at ISIs of 1 and 2.5 ms were significantly reduced in ALS. The SICI curve was altered, displaying a solitary peak. Discriminant analysis revealed that the combination of SICI 2.5 ms and the mean SICF between 1 and 1.8 ms ISIs was the most sensitive parameter to distinguish patients with ALS from healthy participants. DISCUSSION: Along with the reduced SICI and its altered shape, connectivity between motor cortical circuits is changed in ALS. Combination with SICF increases the diagnostic utility of SICI in ALS.

Impaired short- and long-latency afferent inhibition in amyotrophic lateral sclerosis.

INTRODUCTION: To test the hypothesis of impaired cholinergic activity in amyotrophic lateral sclerosis (ALS), we studied short- and long-latency afferent inhibition (SAI and LAI). METHODS: The ulnar nerve was stimulated at the wrist preceding transcranial magnetic stimulation (TMS), 21 ms for SAI and 200 ms for LAI, in 21 patients and 17 control subjects. Short-interval intracortical inhibition (SICI) and cognitive function was assessed in ALS patients using automatic threshold tracking and the Montreal Cognitive Assessment (MoCA). RESULTS: The SAI paradigm resulted in inhibition in all control subjects, whereas inhibition was observed in 13 of 21 (62%) patients. Mean SAI and LAI values were significantly reduced in ALS. No significant correlation existed between afferent inhibition and other neurophysiological data. The MoCA was normal in all but 1 patient. DISCUSSION: LAI and SAI are both impaired in ALS, probably unrelated to increased cortical excitability or cognitive dysfunction. Muscle Nerve 59:699-704, 2019.

Spinal excitability changes do not influence the mechanisms of split-hand syndrome in amyotrophic lateral sclerosis.

INTRODUCTION: We studied spinal excitability and its relation to motor unit action potential (MUAP) changes in the thenar and hypothenar muscles in patients with amyotrophic lateral sclerosis (ALS). METHODS: Quantitative MUAP and peak ratio interference analyses were performed, and cutaneous silent period (CutSP) was measured in the abductor digiti minimi (ADM) and first dorsal interosseous (FDI) muscles of patients with ALS and controls. RESULTS: Patients with ALS revealed more prominently increased duration (P = 0.002), number of phases (P = 0.02), size index (P = 0.02), and thickness (P = 0.02) in ADM than in FDI. The number of small segments was significantly decreased in ADM (P = 0.036) compared with controls. CutSP latency was prolonged in both ADM and FDI in ALS (P < 0.05). DISCUSSION: Although the reinnervation capacity was notably higher in the ADM of patients with ALS, the lack of a significant difference in CutSP measurements between ADM and FDI argues against spinal excitability changes in the development of split-hand syndrome. Muscle Nerve 58: 503-508, 2018.

Reduced Occipital Cortex Excitability in Amyotrophic Lateral Sclerosis.

PURPOSE: In addition to motor cortex involvement, sensory abnormalities have been demonstrated in amyotrophic lateral sclerosis (ALS), including structural and metabolic alterations in the occipital cortex. The aim of this study was to examine occipital excitability changes in ALS. METHODS: Twenty-one patients with ALS and 16 healthy subjects were enrolled into the study. Phosphene experience and phosphene threshold were studied to assess occipital excitability. Cognitive function was evaluated in both groups by means of Montreal Cognitive Assessment and Addenbrooke's Cognitive Examination-Revised visuospatial score tests. RESULTS: Phosphene was experienced in 13 (81.3%) healthy subjects and 9 (42.9%) patients with ALS ( P = 0.04). The mean phosphene threshold was not significantly different between the two groups. No correlation existed between phosphene threshold and motor cortical excitability parameters, ALS Functional Rating Scale Revised, Montreal Cognitive Assessment, and Addenbrooke's Cognitive Examination-Revised scores. CONCLUSIONS: Visual cortex is affected, and the occipital excitability is reduced in ALS, without any relation to motor cortical excitability changes, providing another clue suggestive of sensory involvement in ALS.

Autonomic nervous system dysfunction and serum levels of neurotoxic and neurotrophic cytokines in patients with cobalamin deficiency.

OBJECTIVE: The imbalance between neurotoxic cytokine tumor necrosis factor-α (TNF-α) and neurotrophic cytokines epidermal growth factor (EGF) and interleukin-6 (IL-6) plays a role in the pathogenesis of cobalamin (Cbl) deficiency-induced neuropathy. The aim of this study was to evaluate autonomic nervous system dysfunction and to look for any relationship between autonomic nervous system disturbances and serum cytokine levels (TNF-α, EGF, IL-6) in patients with Cbl deficiency. METHODS: Serum levels of TNF-α, EGF and IL-6 were studied in patients with Cbl deficiency (n=41) and a healthy control group (n=17) and after 3 months in patients who underwent Cbl replacement therapy (n=22). All patients with Cbl deficiency underwent electrophysiological studies (EPS) for the diagnosis of neuropathy. Statistical analysis was performed using SPSS for Windows 11.5 software. RESULTS: With EPS, 29 of 41 Cbl-deficient patients (70.73%) demonstrated neurological dysfunction [3 (7.32%), 19 (46.34%) and 7 (17.07%) patients with sensorimotor peripheral neuropathy, parasympathetic, and sympathetic autonomic dysfunction, respectively]. Although there was no significant difference in serum levels of EGF and IL-6 between patients with versus without autonomic dysfunction, levels were significantly lower in Cbl- deficient patients than healthy controls. CONCLUSION: Presence of autonomic dysfunction seems to be a frequent neurological finding in patients with Cbl deficiency. However, we could not find any relationship between serum cytokine levels and autonomic dysfunction by EPS.

Miller-Fisher syndrome associated with chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a frequent hematological malignancy, with meningeal or peripheral nerve infiltrations being the most commonly encountered neurological complications. In this report, we describe a CLL patient with Miller-Fisher syndrome (MFS) who responded to immune modulation with plasmapheresis. A 47-year-old man diagnosed as B-cell CLL admitted with neutropenic fever. He complained of diplopia and numbness of both arms. Neurological examination revealed a bilateral external ophthalmoplegia, dysphagia, dysarthria, mild shoulder girdle muscle weakness and gait ataxia, accompanied by absent tendon reflexes. Nerve conduction studies were indicative of a predominantly axonal sensori-motor peripheral neuropathy. This association of CLL with MFS had not been previously reported in the literature.

Osteomalacic myopathy associated with coexisting coeliac disease and primary biliary cirrhosis.

OBJECTIVE: To report a patient with coeliac disease (CD) associated with primary biliary cirrhosis (PBC) who presented with myopathy without classical symptoms of CD. CLINICAL PRESENTATION AND INTERVENTION: A 42-year-old woman presented with inability to walk and marked loss of motor function. She had elevated liver enzymes with a cholestatic pattern. Antimitochondrial antibody M2 band, anti-endomysial antibody, antigliadin IgA and IgM were positive. Histopathologic findings of the liver revealed PBC and duodenal biopsy was consistent with CD. She was also found to have osteomalacia. She showed slow response to gluten-free diet, but accelerated full recovery with vitamin D replacement. CONCLUSION: In PBC patients with subclinical CD and myopathy, vitamin D status can provide a basis for treatment.

Multiple system atrophy presenting with acute respiratory failure due to diaphragmatic dysfunction.

Sleep related respiratory dysfunction and vocal cord paralysis are considered to be the major factors responsible for respiratory failure in multiple system atrophy (MSA). We report a patient initially presenting with alveolar hypoventilation culminating in respiratory failure, ultimately diagnosed as MSA. No central sleep apnea or marked paralysis of the vocal cords was noted. The most likely cause for the respiratory failure was thought to be the weakness of respiratory musculature. This case emphasizes the need that MSA should be added to the differential diagnosis of unexplained hypercapnic respiratory failure.