From the Guidelines
Testing for ALS involves a comprehensive diagnostic process, starting with a thorough neurological examination and medical history review, followed by electromyography (EMG) and nerve conduction studies (NCS) to detect signs of nerve damage, as these tests are key in diagnosing ALS 1.
Diagnostic Approach
The diagnosis of ALS typically involves a series of tests to rule out other conditions with similar symptoms. These include:
- Electromyography (EMG) and nerve conduction studies (NCS) to measure electrical activity in muscles and nerves
- MRI scans of the brain and spinal cord to exclude other conditions like tumors or spinal cord compression
- Blood and urine tests to rule out metabolic or toxic causes of symptoms
- In some cases, a lumbar puncture (spinal tap) may be conducted to analyze cerebrospinal fluid
- Muscle biopsies are occasionally needed to exclude other muscle diseases
- Genetic testing may be recommended, especially for those with a family history of ALS
Imaging Studies
Imaging studies, such as MRI, are relied upon mainly to exclude other conditions with similar clinical presentations rather than confirm or facilitate the diagnosis of ALS 1. However, MRI can show abnormal signal on T2/FLAIR or proton density–weighted images, which can be seen anywhere within the cortico-spinal tracts from the subcortical white matter to the pons 1.
Clinical Evaluation
Clinical evaluation of dysphagia should include evaluation of lip closure and evidence of saliva pooling, tongue strength, mobility and tone, chewing capacity, palatal movement in response to tactile stimulation, the quality and strength of the cough as well as phoniatric function 1. Instrumental assessment of dysphagia, such as videofluoroscopy (VFS) or fiberoptic endoscopic evaluation of swallowing (FEES), may be performed according to local protocols, in patients with symptoms of dysphagia 1.
Diagnostic Criteria
The diagnosis is typically made based on the El Escorial criteria, which consider clinical symptoms, signs of upper and lower motor neuron degeneration, and the progressive spread of symptoms 1. This comprehensive approach is necessary because ALS symptoms can mimic other neurological conditions, and early accurate diagnosis is crucial for appropriate management and treatment planning. The most recent and highest quality study recommends a comprehensive diagnostic approach, including EMG, NCS, and imaging studies, to diagnose ALS 1.
From the Research
Testing for ALS
- There are no specific tests mentioned in the provided studies for diagnosing ALS, but rather discussions on the treatment and management of the disease using riluzole 2, 3, 4, 5, 6.
- The studies focus on the efficacy of riluzole in prolonging survival and slowing the progression of ALS, with varying results reported 2, 3, 4.
- Riluzole is described as the only approved treatment for ALS, with a modest but significant extension of lifespan in patients 3, 6.
- The mechanisms of action of riluzole are discussed, including its effects on neural activity and neurotransmitter release 6.
- The importance of staging in ALS clinical trials is highlighted, with the King's clinical staging system used to assess the stage at which survival benefit occurs 4.
Riluzole Treatment
- Riluzole is shown to prolong survival in the last clinical stage of ALS, with a 35% reduction in mortality reported in a clinical trial 4.
- The drug is generally safe and well-tolerated, with minor effects on normal respiration parameters and inhibition of hypoxia-induced gasping 6.
- Hormetic mechanisms are proposed to subserve riluzole-induced effects in neuroprotection against ALS, with implications for research and clinical practice 5.
- Real-world evidence suggests that riluzole therapy may afford greater extension of survival and improvements in median survival times than reported in randomized controlled trials 2.