Diagnostics of Amyotrophic Lateral Sclerosis: Up to Date

Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by gradual loss of upper and lower motor neurons and their pathways, usually without affecting the extraocular and sphincter muscles. The cause of the disease is not yet known. It is a chain of subsequent events, ending in programmed cell death in selective neuronal subpopulations. The prognosis for survival is rather short with a median of 2 to 4 years. Survival may be prolonged based on prompt diagnosis, ALS subtype and proper management with supportive treatment (tracheostomy, gastrostomy, etc.). According to the clinical picture, the typical form of ALS with upper and lower motoneuron involvement and progressive bulbar paralysis with bulbar muscle involvement is observed. The ALS form with progressive muscle atrophy, where only the lower motoneuron is affected, and primary lateral sclerosis with only upper motoneuron damage are rare. Familiar forms of ALS (FALS) associated with specific genes (the most common is C9orf72) have been discovered. FALS is usually associated with dementia (frontotemporal lobar dementia, FTLD), behavioral disorders, cognitive dysfunction and impairment of executive functions. The diagnosis of ALS is determined by excluding other conditions and utilizing clinical examinations, laboratory and genetic tests and nerve conduction/needle electromyography studies (EMG). Needle EMG records abnormal activities at rest and looks for neurogenic patterns during muscle contraction. Motor evoked potentials after transcranial magnetic stimulation remain the test of choice to identify impairment of upper motor neurons. New biochemical, neurophysiological and morphological biomarkers are extensively studied as early diagnostic and prognostic factors and have implications for clinical trials, research and drug development.

Study on the Diagnostic Value of Neuroelectrophysiological Examination in Patients with Amyotrophic Lateral Sclerosis

“…The abnormal rate of EMG in ALS cases was as high as 85%. EMG remains a basic method to determine the loss of motor units, which include anterior horn cell, motor nerve, neuromuscular junction, and the muscle fibers [ 8 ]. In the process of EMG detection, it was found that in patients with early ALS, EMG mostly showed extensive neurogenic damage at three or more sites, so EMG was an important tool to assist in the diagnosis of ALS.…”

Analysis of SOD1 and C9orf72 mutations in patients with amyotrophic lateral sclerosis in Antioquia, Colombia

“…This, along with the complete absence of G93A and D90A mutations of SOD1 in the patients, is an unexpected and relevant finding about amyotrophic lateral sclerosis genetics, its physiopathology and other neurodegenerative conditions. It is therefore necessary to confirm whether this genotype of 8 repeats in C9orf72 is pathologic in our population and to determine its importance as a diagnostic biomarker or as a risk factor for amyotrophic lateral sclerosis, as it is currently being done in other populations (43)(44)(45).…”

A novel TFG variant of uncertain significance in amyotrophic lateral sclerosis: A case report and review of literature

“…The other possibilities were ruled out based on the history and clinical examination. He was then diagnosed ALS on the basis of Gold Coast criteria [ [5] , [6] , [7] ]. On exome sequencing [ 8 ], an atypical gene was isolated from gene sequencing as shown in Table 1 .…”