Initial symptoms: Very Early ALS Symptoms:
Muscle weakness and twitching are hallmark early symptoms of ALS. While occasional muscle twitches are typically benign, persistent fasciculations or muscle cramps that linger or recur over several weeks should prompt a medical evaluation. It's crucial to be vigilant about subtle changes in muscle strength, coordination, and even slight alterations in speech, chewing, or swallowing abilities.
As mentioned earlier, these seemingly minor shifts could be early indicators of ALS progression. However, It's important to note that chronic muscle twitching without other muscle-related symptoms, especially if experienced for years, may not necessarily signal ALS. Some individuals are simply more prone to persistent muscle twitches. Nonetheless, any new or concerning muscle symptoms, particularly when accompanied by weakness or functional changes, should be assessed by a healthcare professional to rule out ALS or other neurological conditions[6]
Persistent muscle weakness, twitching, or cramps lasting several weeks should prompt a medical evaluation to rule out ALS or other neurological conditions.
Changes in motor function and coordination are often among the earliest signs of ALS. Individuals may notice subtle alterations in their ability to perform routine tasks, such as buttoning clothes or tying shoelaces[7]. These difficulties can manifest as frequent tripping or falling, indicating a decline in balance and coordination.
As the disease progresses, muscle weakness typically becomes more pronounced, often starting on one side of the body, affecting either an arm or a leg[8]. This asymmetrical weakness is a hallmark of early ALS. Additionally, people may experience changes in their speech, such as slurred words or slower speech patterns, which are indicative of the disease's impact on bulbar muscles.
It's crucial to note that these symptoms can develop gradually and may initially be mistaken for normal aging, making early recognition challenging. This underscores the importance of staying vigilant and seeking professional medical advice when persistent changes are noticed.
Speech and swallowing difficulties are often among the earliest manifestations of ALS, particularly in bulbar forms of the disease. These symptoms can be crucial indicators for accurate diagnosis and early intervention. Voice changes may include harshness, strain-strangled quality, breathiness, tremor, and pitch abnormalities. In some cases, features resembling spasmodic dysphonia have been observed.
Swallowing problems typically progress in a predictable pattern, beginning with difficulties managing tough textures, fragmented foods, and thin liquids. As the disease advances, patients may experience severe challenges controlling liquids during swallowing and maintaining adequate nutritional intake. The progression of dysphagia in bulbar ALS has been categorized into five stages, ranging from normal eating habits to complete inability to take food orally.
Notably, laryngeal dysfunction can manifest as failure of the larynx to move properly during swallowing, increasing the risk of aspiration. These bulbar symptoms often result from the involvement of multiple cranial nerves, including the trigeminal, facial, hypoglossal, glossopharyngeal, and vagus nerves. The complex interplay of spasticity, flaccidity, and compensatory strategies contributes to the variability of phonatory and swallowing symptoms observed among ALS patients. (ALS United)
More pronounced symptoms
Common misdiagnoses
Misdiagnosis of ALS is not uncommon, with studies reporting rates between 3.9% and 8%[9]. Common conditions mistaken for ALS include structural spinal pathology, hereditary spastic paraplegia (HSP), and multifocal motor neuropathy (MMN). Cervical spondylosis and spinal stenosis can mimic ALS symptoms, highlighting the importance of thorough spinal imaging. HSP, characterized by symmetric lower extremity spasticity, may be misdiagnosed as ALS, especially in cases with long symptom duration. MMN, an immune-mediated neuropathy, can present similarly to ALS but often responds to immunoglobulin therapy. Other potential misdiagnoses include multiple sclerosis, Parkinson's disease, and spinal muscular atrophy[10].
Notably, lack of disease progression is the most common reason for diagnostic reconsideration. Atypical features that should prompt consideration of alternative diagnoses include symmetric findings, disease duration greater than 2 years at presentation, young age at onset (less than 50), and pain. The complexity of ALS diagnosis underscores the importance of longitudinal evaluation and continual reassessment of patients clinical presentations.
Diagnostic Test
Step 1: Have a Neurological Exam
The diagnosing ALS process begins with an examination by a neurologist. This will include a detailed review of the patient's family, work, and environmental history. During the exam, the neurologist will look for typical features of ALS, such as:
Step 2: Undergo Diagnostic ALS Testings
The next step to diagnose ALS often involves a series of tests. These typically include an MRI (magnetic resonance imaging) of the neck, and sometimes of the head and lower spine, along with an EMG (electromyography) which tests nerve conduction, and a series of blood tests. Sometimes urine tests, genetic tests, or a lumbar puncture (also called a spinal tap) are also necessary.
Electromyography (EMG)
The EMG is a very important part of the diagnostic process for ALS.
In the first part of the EMG, small electric shocks are sent through the nerves to measure their conduction speed and detect any potential nerve damage. The shocks are often similar to static electricity but may sometimes feel a bit stronger. This phase of the test determines whether the individual has "nerve block", which is a feature of a different disease called multifocal motor neuropathy. There is a chart at the end of this section that further explains this disease. It also tests whether the nerves that communicate sensation are affected, which may also indicate a disease other than ALS.In the second part of the EMG, the electrical activity of specific muscles is tested by inserting a very fine needle into them. The needle is used to assess the pattern of electrical activity in these muscles. Unlike the first part of the test, no electric shocks are involved, and the needle does not inject or extract anything from your muscles.
MRI
An MRI is a painless, non-invasive procedure that offers a very detailed picture of the spinal cord, the nerves that come out of the spinal cord, and the bones and connective tissues that surround and protect the spinal cord. It shows more detail than a CAT (computed axial tomography) scan or X-rays. The MRI will help rule out conditions like pressure on the spinal cord or major nerves (such as from a herniated vertebral disk), multiple sclerosis, and tumors or bony abnormalities that might compress the nerves. Additionally, it can help detect vascular changes and strokes that may impact the spinal cord or brain.
The MRI procedure takes about 30 minutes to complete. Patients will be asked to recline inside a machine that is basically a large, rotating magnet. The test is noisy, but painless. If individuals experience discomfort in small, confined spaces, it's crucial to inform the doctor before the MRI starts. This allows for the possibility of providing medication to help the person relax.
Lab Tests
Specialized blood tests are also performed, such as autoimmune antibody tests, anti-GM1 antibody tests, and tests looking for high levels of protein in the blood and urine that may be related to some types of cancers. Depending on the individual's work and environmental history, the doctor may also test his or her urine for heavy metals.