What is ALS?
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that causes muscle weakness and paralysis. ALS is also known internationally as motor neurone disease (MND) or Lou Gehrig’s disease.
In people with ALS, motor neurons in the spinal cord, brainstem and brain gradually die. These nerve cells control the muscles in the body. As the motor neurons become less able to send signals to the muscles, muscle weakness progressively develops.
ALS can develop at any age in adulthood, but it most commonly develops between the ages of 40 and 60. In Europe alone, around 40,000 people live with ALS. Worldwide, 175,000 people die from ALS each year. There are no major differences in incidence and prevalence between countries or continents, with the exception of some regions in the Western Pacific. Progressive muscular atrophy (PMA) and primary lateral sclerosis (PLS) are related to ALS, but are less common.
Symptoms
The main symptom of ALS, PMA and PLS is progressive muscle weakness and/or spasticity.
Progressive muscle weakness
The first symptoms of ALS often include reduced strength in the arms or legs, or difficulty speaking, swallowing or breathing. As the muscles receive fewer signals from the motor neurons, they gradually become thinner and weaker. The disease causes increasing limitations in daily activities. When the motor neurons have completely died, the brain can no longer control the muscles, resulting in paralysis. The senses (touch, taste, vision, smell and hearing) usually remain intact. The functions of the bowel, bladder and heart are also generally unaffected.
Muscle cramps and spasticity
Muscle cramps usually occur in a single muscle. During a cramp, the muscle becomes visibly tense. Cramps often occur after forceful muscle contraction, particularly when the muscle is shortened. A cramp is acutely painful and often only stops when the muscle is stretched. The muscle may remain sore afterwards, and swelling can sometimes occur.
In healthy people, cramps commonly occur in the calf muscles, foot muscles and hamstrings. In people with ALS and PLS, cramps can also occur in other muscles, such as those in the hands, neck and tongue. As the disease progresses, muscle cramps often gradually decrease.
Muscle stiffness and spasms, also known as spasticity, can also occur in ALS.
Cognitive symptoms
Around half of people with ALS, PMA or PLS experience mild changes in thinking or behaviour. Most people and their families experience little or no impact from these changes. In approximately 5 to 10% of people with ALS, PMA or PLS, the disease is associated with frontotemporal dementia (FTD). FTD is a form of dementia in which significant changes in behaviour are often prominent.
What causes ALS?
The exact cause of ALS is not known. Around 10% of people with ALS have a hereditary form of the disease. This hereditary form is often already known to run in the family.
A genetic mutation has been identified in approximately half of people with familial ALS. Other have sporadic ALS, meaning that the cause involves a combination of genetic predisposition and environmental factors, such as lifestyle and exposure to harmful substances.
Diagnosing ALS
There is no single test that can confirm or rule out ALS, PMA or PLS. A neurologist makes the diagnosis based on the symptoms and the results of a neurological examination, while also ruling out other possible conditions. Diagnosing ALS, PMA or PLS requires specialised knowledge and experience. People in the Netherlands suspected of having one of these conditions are therefore often referred to ALS Centre Netherlands.
Disease progression and life expectancy in ALS
The rate at which ALS progresses varies considerably from person to person. On average, people with ALS die around three years after the first symptoms appear. Twenty per cent of people live for more than five years. Respiratory muscle failure is usually the cause of death in people with ALS. PMA has a rapidly progressive and a slowly progressive form. Even with the slowly progressive form, a person may eventually become largely paralysed, but this takes longer. With the rapidly progressive form, deterioration occurs more quickly. In some people, PMA can progress to ALS after months or years.
PLS has a relatively slow disease progression. In some people with PLS, the condition progresses to ALS within four years of the onset of symptoms.
Disease progression in PMA and PLS
PMA has a rapidly progressive and a slowly progressive form. Even with the slowly progressive form, a person may eventually become largely paralysed, but this takes longer. With the rapidly progressive form, deterioration occurs more quickly. In some people, PMA can progress to ALS after months or years.
PLS has a relatively slow disease progression. In some people with PLS, the condition progresses to ALS within four years of the onset of symptoms.
Treatment for ALS
For most people with ALS, there is currently no treatment that stops or reverses the disease. A treatment is currently available for approximately 1% of people with ALS who have a rare mutation in the SOD1 gene.
The medicine riluzole is also approved in Europe. Riluzole slows the decline in muscle strength but does not cure ALS. On average, people taking riluzole live three to six months longer.
Good care and support for people with ALS and their families is very important. In the Netherlands, after a diagnosis, the neurologist refers the person to a regional ALS treatment team. These specialised teams are based in rehabilitation centres or hospital rehabilitation departments and have extensive experience in caring for people with ALS. An ALS treatment team supports people with ALS, PMA and PLS, treats symptoms and helps prevent complications. The team can also support partners and family members.
The search for a treatment
There is currently no cure for most people living with ALS. ALS Centre Netherlands works with European and international partners to find effective treatments for ALS.
TRICALS is the largest research initiative in Europe focused on finding treatments for ALS, PMA and PLS. Within TRICALS, we work with ALS centres across Europe to make clinical drug development more efficient. The aim is to conduct more and faster clinical research so that effective treatments for ALS can reach patients sooner.
Clinical trials at the ALS Centre are conducted as part of TRICALS. Patients registered with TRICALS receive information about new clinical trials. The TRICALS website also provides an overview of ongoing clinical trials and information about which studies are currently looking for participants.