pathologist. these health professionals can teach people adaptive strategies such as techniques to help them speak louder and more clearly. as als progresses, speech-language pathologists can recommend the use of augmentative and alternative communication such as voice amplifiers, speech-generating devices (or voice output communication devices) or low-tech communication techniques such as head-mounted laser pointers, alphabet boards or yes/no signals. in a study published in 2022, a completely locked-in als patient was fitted with two 64-bit brain implant microarrays in his motor cortex in 2020. using audible feedback from his own intentional neural firing rates, he was able to communicate letters to form phrases. this is the first example of communication at length with a fully locked-in als patient. nutrition a gastrostomy tube is placed through the wall of the abdomen into the stomach. preventing weight loss and malnutrition in people with als improves both survival and quality of life. weight loss in als is caused by muscle wasting due to motor neuron death increased resting energy expenditure, and decreased food intake. difficulty swallowing (dysphagia) develops in about 85% of people with als at some point over the course of their disease and is a major cause of decreased food intake, leading to malnutrition and weight loss. it is important to regularly assess the weight and swallowing ability of people with als. initially, dysphagia may be managed by dietary changes and modified swallowing techniques. difficulty swallowing liquids usually develops first and can be managed by switching to thicker liquids like fruit nectar or smoothies, or by adding fluid thickeners to thin fluids like water and coffee. people with als should eat soft, moist foods, which tend to be easier to swallow than dry, crumbly, or chewy foods. they should also be instructed on proper head posture during swallowing, which can make swallowing easier. there is tentative evidence that high-calorie diets may prevent further weight loss and improve survival. a feeding tube should be considered if someone with als loses 5% or more of their body weight or if they cannot safely swallow food and water. this can take the form of a gastrostomy tube, in which a tube is placed through the wall of the abdomen into the stomach, or a nasogastric tube, in which a tube is placed through the nose and down the esophagus into the stomach. a gastrostomy tube is more appropriate for long-term use than a nasogastric tube, which is uncomfortable and can cause esophageal ulcers. the feeding tube is usually inserted by a percutaneous endoscopic gastrostomy procedure (peg). there is weak evidence that peg tubes improve survival. peg insertion is usually performed with the intent of improving quality of life by sustaining nutrition and medication intake. this reduces the risk of weight loss and dehydration and can decrease anxiety from extended mealtimes and decreased oral food intake. end-of-life care palliative care, which relieves symptoms and improves the quality of life without treating the underlying disease, should begin shortly after someone is diagnosed with als. early discussion of end-of-life issues gives people with als time to reflect on their preferences for end-of-life care and can help avoid unwanted interventions or procedures. once they have been fully informed about all aspects of various life-prolonging measures, they can fill out advance directives indicating their attitude toward noninvasive ventilation, invasive ventilation, and feeding tubes. late in the disease course, difficulty speaking due to muscle weakness (dysarthria) and cognitive dysfunction may impair their ability to communicate their wishes regarding care. continued failure to solicit the preferences of the person with als may lead to unplanned and potentially unwanted emergency interventions, such as invasive ventilation. if people with als or their family members are reluctant to discuss end-of-life issues, it may be useful to use the introduction of gastrostomy or noninvasive ventilation as an opportunity to bring up the subject. hospice care, or palliative care at the end of life, is especially important in als because it helps to optimize the management of symptoms and increases the likelihood of a peaceful death. it is unclear exactly when the end-of-life phase begins in als, but it is associated with significant difficulty moving, communicating, and, in some cases, thinking. although many people with als fear choking to death (suffocating), they can be reassured that this occurs rarely, about 0–3% of the time. about 90% of people with als die peacefully. in the final days of life, opioids can be used to treat pain and dyspnea, while benzodiazepines can be used to treat anxiety. epidemiology als is the most common motor neuron disease in adults and the third most common neurodegenerative disease after alzheimer's disease and parkinson's disease. worldwide the number of people who develop als yearly is estimated to be 1.9 people per 100,000 per year, while the number of people who have als at any given time is estimated to be about 4.5 people per 100,000. in europe, the number of new cases a year is about 2.6 people per 100,000, while the number affected is 7–9 people per 100,000. the lifetime risk of developing als is 1:350 for european men and 1:400 for european women. men have a higher risk mainly because spinal-onset als is more common in men than women. the number of those with als in the united states in 2015 was 5.2 people per 100,000, and was higher in whites, males, and people over 60 years old. the number of new cases is about 0.8 people per 100,000 per year in east asia and about 0.7 people per 100,000 per year in south asia. about 80% of als epidemiology studies have been conducted in europe and the united states, mostly in people of northern european descent. there is not enough information to determine the rates of als in much of the world, including africa, parts of asia, india, russia, and south america. there are several geographic clusters in the western pacific where the prevalence of als was reported to be 50–100 times higher than the rest of the world, including guam, the kii peninsula of japan, and western new guinea. the incidence in these areas has decreased since the 1960s; the cause remains unknown. estimated prevalence of als in the united states by age group, 2012–2015 people of all races and ethnic backgrounds may be affected by als, but it is more common in whites than in africans, asians, or hispanics. in the united states in 2015, the prevalence of als in whites was 5.4 people per 100,000, while the prevalence in blacks was 2.3 people per 100,000. the midwest had the highest prevalence of the four us census regions with 5.5 people per 100,000, followed by the northeast (5.1), the south (4.7), and the west (4.4). the midwest and northeast likely had a higher prevalence of als because they have a higher proportion of whites than the south and west. ethnically mixed populations may be at a lower risk of developing als; a study in cuba found that people of mixed ancestry were less likely to die from als than whites or blacks. there are also differences in the genetics of als between different ethnic groups; the most common als gene in europe is c9orf72, followed by sod1, tardbp, and fus, while the most common als gene in asia is sod1, followed by fus, c9orf72, and tardbp. als can affect people at any age, but the peak incidence is between 50 and 75 years and decreases dramatically after 80 years. the reason for the decreased incidence in the elderly is unclear. one thought is that people who survive into their 80s may not be genetically susceptible to developing als; alternatively, als in the elderly might go undiagnosed because of comorbidities (other diseases they have), difficulty seeing a neurologist, or dying quickly from an aggressive form of als. in the united states in 2015, the lowest prevalence was in the 18–39 age group, while the highest prevalence was in the 70–79 age group. sporadic als usually starts around the ages of 58 to 63 years, while familial als starts earlier, usually around 47 to 52 years. the number of als cases worldwide is projected to increase from 222,801 in 2015 to 376,674 in 2040, an increase of 69%. this will largely be due to the aging of the world's population, especially in developing countries. history the french neurologist jean-martin charcot coined the term amyotrophic lateral sclerosis in 1874. american baseball player lou gehrig. in some countries, especially the united states, als is called "lou gehrig's disease." descriptions of the disease date back to at least 1824 by charles bell. in 1850, françois-amilcar aran was the first to describe a disorder he named "progressive muscular atrophy", a form of als in which only the lower motor neurons are affected. in 1869, the connection between the symptoms and the underlying neurological problems were first described by jean-martin charcot, who initially introduced the term amyotrophic lateral sclerosis in his 1874 paper. flail arm syndrome, a regional variant of als, was first described by alfred vulpian in 1886. flail leg syndrome, another regional variant of als, was first described by pierre marie and his student patrikios in 1918. diagnostic criteria in the 1950s, electrodiagnostic testing (emg and ncv) began to be used to evaluate clinically suspected als. in 1969 edward h. lambert published the first emg/ncs diagnostic criteria for als, consisting of four findings he considered to strongly support the diagnosis. in 1990, the world federation of neurology (wfn) held a meeting at el escorial, spain, to come up with precise diagnostic criteria for als to help standardize clinical trials; the resulting "el escorial" criteria were published in 1994. in 1998, the wfn held another meeting to revise the criteria at airlie house in warrenton, virginia; the resulting "airlie house" or "el escorial revised" criteria were published in 2000. in 2006, a meeting was held on awaji island in japan to discuss how to use emg and ncv tests to help diagnose als earlier; the resulting "awaji" criteria were published in 2008. name