Because the list of possible MS symptoms is so long and varied, it is inevitable that there will be some overlap between some MS symptoms and many other diseases and disorders, especially neurological ones. Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is no exception. However, distinct differences in the symptoms of MS and ALS become evident pretty quickly.
One huge difference in the presentation of these diseases is that the symptoms of ALS all involve nerves that control voluntary muscle movement, whereas the nerves affected in MS affect both voluntary and involuntary muscle movement.
First Symptoms in ALS and MS
80% of people with ALS have muscle weakness on one side of their body as their first symptom. This is usually in the hands (such as trouble writing or picking up tiny objects), shoulder (such as difficulty lifting arms above the head to do tasks like combing their hair or reaching for an object), or feet/legs (usually seen as "foot drop" or difficulty climbing stairs). The other initial ALS symptoms usually involve trouble speaking (dysarthria) or swallowing (dysphagia).
In contrast, the first symptoms usually experienced by people with MS are often parasthesias (numbness or tingling in extremities) or optic neurtis. Of course, ANY of the symptoms of MS can show up first; these are just the most common.
Similar Symptoms of ALS and MS
Muscle Weakness in Arms and Legs: People with ALS will experience a decline in the strength and ability to use the muscles in their arms and legs. The muscles actually atrophy, making it difficult to walk -– eventually an assistive device (walker, wheelchair or scooter) will be needed by everyone with ALS. While many people with MS certainly do experience problems walking, this is not universal.
Speech Difficulties: Dysarthria is the most common speech disorder in people with ALS and in people with MS. People with this symptom speak slowly, softly, in strange rhythms, or slur their words. Although this can make it difficult to understand their speech, the meaning of what they are saying is normal. In people with ALS, the dysarthria tends to get progressively worse, whereas in MS, it is usually intermittent (comes and goes). In addition, it is usually more severe in people with ALS.
People with MS often have additional symptoms that interfere with communication, such as dysphasia, which are problems understanding or communicating spoken or written words. These are one type of MS-related cognitive dysfunction. People with ALS typically do not experience these types of symptoms. Although some people with ALS do experience some cognitive dysfunction, these symptoms are usually more subtle.
Swallowing Problems: People with ALS also commonly experience dysphagia, which means they have difficulty swallowing. This will often progress to the point that a feeding tube or other means of feeding will need to be introduced. While people with MS may also have this symptom, it is usually much less severe and people may not be aware of it, besides occasional swallowing problems that feel like gagging or coughing when eating.
Breathing Problems: When the muscles controlling respiration begin to atrophy, the person with ALS begins to experience problems breathing, as they simply cannot take enough air into their lungs. At some point, many people with ALS will use a device to help them breathe, often starting with noninvasive ventilation -- wearing a mask that delivers oxygen. (In case you are wondering, breathing is considered a "voluntary" muscle movement, as we can control, to some extent, the pace and rhythm of our breathing.)
Breathing problems also occur in people with MS, but usually not to the same extent -– it is extremely rare for MS-related respiratory problems to require breathing assistance. It has been shown that lung function is lower than normal in most people with MS, but most people do not notice it or are only bothered by shortness of breath upon exertion, like when climbing stairs or moving quickly.