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ObjectivePlasma phosphorylated tau (p-tau181) is reliably elevated in Alzheimer’s disease (AD), but less explored is its specificity relative to other neurodegenerative conditions. Here we find novel evidence that plasma p-tau181 is elevated in amytrophic lateral sclerosis (ALS), a neurodegenerative condition typically lacking tau pathology. We performed a detailed clinical evaluation to unravel the potential source of this unexpected observation.MethodsPatients were clinically or pathologically diagnosed with ALS (n=130) or AD (n=82), or were healthy non-impaired controls (n=33). Receiver operating characteristic (ROC) curves were analyzed and area under the curve (AUC) was used to discriminate AD from ALS. Within ALS, Mann-Whitney-Wilcoxon tests compared analytes by presence/absence of upper motor neuron (UMN) and lower motor neuron (LMN) signs. Spearman correlations tested associations between plasma p-tau181 and postmortem neuron loss.ResultsA Wilcoxon test showed plasma p-tau181 was higher in ALS than controls (W=3297, p=0.0000020), and ROC analyses showed plasma p-tau181 poorly discriminated AD and ALS (AUC=0.60). In ALS, elevated plasma p-tau181 was associated with LMN signs in cervical (W=827, p=0.0072), thoracic (W=469, p=0.00025), and lumbosacral regions (W=851, p=0.0000029). In support of LMN findings, plasma p-tau181 was associated with neuron loss in the spinal cord (rho=0.46, p=0.017), but not in the motor cortex (p=0.41). CSF p-tau181 and plasma neurofilament light chain (NfL) were included as reference analytes, and demonstrate specificity of findings.InterpretationWe found strong evidence that plasma p-tau181 is elevated in ALS and may be a novel marker specific to LMN dysfunction.

We describe a patient with both neurofibromatosis type 1 and Charcot-Marie-Tooth disease type 1B. Although one might expect an overwhelming tumor burden due to the combination of these two disorders, the two mutations did not appear to interact.

ALS is a neurodegenerative disease that affects nerve cells in the brain and spinal cord that control voluntary skeletal muscle. The muscle weakness that results from ALS is relentlessly progressive and rehabilitative attempts to strengthen affected muscles usually fail. When managing swallowing and communication disorders in individuals with ALS, the goals are to maximize function and safety through the use of compensatory strategies, energy conservation, and patient and caregiver education and counseling. This paper will review the current methods of assessment and treatment used with this population in the outpatient setting.

Progressive loss of motor neurons causes Amyotrophic Lateral Sclerosis. Patients complain, most often, of progressive weakness in the distal limbs. However, weakness may manifest in any body segment (bulbar, cervical, thoracic, or lumbosacral). The diagnosis of ALS is suggested by clinical examination that reveals both upper and lower motor neuron failure. Formal diagnostic criteria have been developed and validated. Nerve conduction and electromyography studies improve diagnostic sensitivity and exclude some alternate, treatable diagnoses. Likewise, conventional imaging studies and laboratory evaluation refute other diseases that may masquerade as ALS. Experimental imaging and laboratory evaluations may improve ALS diagnosis in the future. The cause of motor neuron death is not known but inherited forms of motor neuron disease may suggest mechanisms. The goal of ALS treatment is control of the symptoms of progressive weakness, especially respiratory insufficiency and dysphagia and is best managed in an integrated clinic.