In physiology, an action potential occurs when the membrane potential of a specific axon location rises and falls: this depolarisation causes adjacent locations to depolarise. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, endocrine cells, in some plant cells. In neurons, action potentials play a central role in cell-to-cell communication by providing for—or with regard to saltatory conduction, assisting—the propagation of signals along the neuron's axon toward synaptic boutons situated at the ends of an axon. In other types of cells, their main function is to activate intracellular processes. In muscle cells, for example, an action potential is the first step in the chain of events leading to contraction. In beta cells of the pancreas, they provoke release of insulin. Action potentials in neurons are known as "nerve impulses" or "spikes", the temporal sequence of action potentials generated by a neuron is called its "spike train".
A neuron that emits an action potential, or nerve impulse, is said to "fire". Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane; these channels are shut when the membrane potential is near the resting potential of the cell, but they begin to open if the membrane potential increases to a defined threshold voltage, depolarising the transmembrane potential. When the channels open, they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential; this causes more channels to open, producing a greater electric current across the cell membrane and so on. The process proceeds explosively until all of the available ion channels are open, resulting in a large upswing in the membrane potential; the rapid influx of sodium ions causes the polarity of the plasma membrane to reverse, the ion channels rapidly inactivate. As the sodium channels close, sodium ions can no longer enter the neuron, they are actively transported back out of the plasma membrane.
Potassium channels are activated, there is an outward current of potassium ions, returning the electrochemical gradient to the resting state. After an action potential has occurred, there is a transient negative shift, called the afterhyperpolarization. In animal cells, there are two primary types of action potentials. One type is generated by the other by voltage-gated calcium channels. Sodium-based action potentials last for under one millisecond, but calcium-based action potentials may last for 100 milliseconds or longer. In some types of neurons, slow calcium spikes provide the driving force for a long burst of emitted sodium spikes. In cardiac muscle cells, on the other hand, an initial fast sodium spike provides a "primer" to provoke the rapid onset of a calcium spike, which produces muscle contraction. In the Hodgkin–Huxley membrane capacitance model, the speed of transmission of an action potential was undefined and it was assumed that adjacent areas became depolarised due to released ion interference with neighbouring channels.
Measurements of ion diffusion and radii have since shown this not to be possible. Moreover, contradictory measurements of entropy changes and timing disputed the capacitance model as acting alone. Nearly all cell membranes in animals and fungi maintain a voltage difference between the exterior and interior of the cell, called the membrane potential. A typical voltage across an animal cell membrane is −70 mV; this means that the interior of the cell has a negative voltage of one-fifteenth of a volt relative to the exterior. In most types of cells, the membrane potential stays constant; some types of cells, are electrically active in the sense that their voltages fluctuate over time. In some types of electrically active cells, including neurons and muscle cells, the voltage fluctuations take the form of a rapid upward spike followed by a rapid fall; these up-and-down cycles are known as action potentials. In some types of neurons, the entire up-and-down cycle takes place in a few thousandths of a second.
In muscle cells, a typical action potential lasts about a fifth of a second. In some other types of cells, in plants, an action potential may last three seconds or more; the electrical properties of a cell are determined by the structure of the membrane that surrounds it. A cell membrane consists of a lipid bilayer of molecules in which larger protein molecules are embedded; the lipid bilayer is resistant to movement of electrically charged ions, so it functions as an insulator. The large membrane-embedded proteins, in contrast, provide channels through which ions can pass across the membrane. Action potentials are driven by channel proteins whose configuration switches between closed and open states as a function of the voltage difference between the interior and exterior of the cell; these voltage-sensitive proteins are known as voltage-gated ion channels. All cells in animal body tissues are electrically polarized – in other words, they maintain a voltage difference across the cell's plasma membrane, known as the membrane potential.
This electrical polarization results from a complex interplay between protein structures embedded in the membrane called ion pumps and ion channels. In neurons, the types of ion channels in the membrane vary across different parts of the cell, giving the dendrites and cell body different electrical properties; as a result, some parts of the membrane of a neuron may be excitable (capable of generating action potentia
A hot tub is a large tub or small pool full of water used for hydrotherapy, relaxation or pleasure. Some have powerful jets for massage purposes. Hot tubs are sometimes known as spas or by the trade name Jacuzzi. In contrast to a typical bathtub, a hot tub is designed to be used by more than one person at a time, with many models accommodating four or more people. Hot tubs are located outdoors, although they can be installed indoors; the water in a hot tub is not changed with each use, but is kept sanitary using methods similar to those used for swimming pool sanitation. Another difference between baths and hot tubs is that soaps and shampoos are not used in wet-jetted hot tubs; the earliest hot tubs were calderas. Therma in Ikaria has been a popular place for hydrotherapy since the 4th century BC; the remains of wrecked marble bathtubs along with a pre-historic aqueduct that have been unearthed from this area bear ample testimony of the place’s popularity in the ancient times. In 737 A. D. Japan's first onsen opened near Izumo and centuries the first ryokan were built, offering food and soaking tubs called ofuro.
In ancient Rome there were three types of baths: baths at home, private baths, public baths. The practice of bathing was so engrained that the Roman legions, during their long occupations in foreign lands, built their own baths at mineral and thermal springs in the newly conquered lands. Examples are found all over Europe. After the fall of the Roman Empire in 476 and the rise of Christianity, cleanliness was abandoned since the Church considered that the practice of bathing a prelude to forbidden behaviour. At Cluny custom required monks to take a full bath at Easter. Private bath-rooms in castles, such as the one at Leeds, could accommodate multiple bathers. From the 13th century onwards, baths came into re-use in southern Europe under the influence of the Moors. In the 1940s hot tubs began to appear in the USA, inspired by the Japanese ofuro. Hydrotherapy pumps were introduced by Jacuzzi. Fiberglass shell hot tubs appeared around 1970 and were soon superseded by cast acrylic shells; the plumbing of the hot tub consists of: A pressure system delivering water to the jets A suction system returning water to the pumps.
A filtration system: the plumbing has to incorporate a filter system to help clean the water. Some models use a separate small 24/7 filter pump while others use programmed settings of the main pumps. Induced air: The jets may use a venturi effect to incorporate air into the water stream for a lighter massage effect; some models use an air blower to force air through a separate set of jets for a different "bubbly" massage effect. An ozone system: ozonation is a common adjunct to water maintenance, if installed will have its own set of hoses and fittings. Hot tubs are heated using an electric or natural gas heater, though there are submersible wood fire hot tub heaters, as well as solar hot water systems. Hot tubs are found at natural hot springs. Effective insulation improves the energy efficiency of a hot tub. There are several different styles of hot tub insulation: some manufacturers fill the entire cabinet with foam, while others insulate the underside of the shell, the inside of the cabinet, or both.
Many manufacturers advertise the superiority of their approach to insulation, but few independent side-by-side comparisons are available. The hot tub pump and hot tub heater represent most of the power consumption in a hot tub and vary in use of power depending on their size. Energy efficiency of the tubs has been studied by the Pacific Electric Company; the industry has responded to the study. After this study, both the California Energy Commission and National Resources Canada have taken an interest in the energy efficiency of portable hot tubs. California's portable electric hot tub listing include R values of thermal insulation, standby watts. Hot tub covers have been shown to reduce most of the evaporative losses from the pool when not in use. With this component of heat loss being 70% a cover with a small R-value is able to achieve as much as a 75% reduction in heating costs when used as opposed to leaving the water surface exposed. There are several different types of spa covers; some covers are better for insulation and therefore are lighter on internal parts and energy efficiency.
Some examples of covers are insulated, rolling, or a tonneau. Since hot tubs are not drained after each use it is necessary to treat the water to keep it attractive and safe, it must be neither too alkaline nor too acidic, must be sanitised to stay free of harmful microorganisms. Due to their high water temperatures, hot tubs can pose particular health risks if not maintained: outbreaks of Legionnaires' Disease have been traced to poorly sanitized hot tubs. Chlorine or bromine are used as sanitizers, but salt water chlorination is starting to become more common. Hot tubs should be periodically shocked, which means oxidizing or breaking down organic material left behind from the sanitizer, as well as non-filterable material such as soap films and perspiration. Sanitation can be aided by a non-chemical ozonator. For aesthetic reasons, for the sanitizer to work properly, water should be neither too alkaline nor too acidic; the hardness level of the water, measured as the amount of dissolved c
A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system; each axon within the nerve is an extension of an individual neuron, along with other supportive cells such as Schwann cells that coat the axons in myelin. Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium; the axons are bundled together into groups called fascicles, each fascicle is wrapped in a layer of connective tissue called the perineurium. The entire nerve is wrapped in a layer of connective tissue called the epineurium. In the central nervous system, the analogous structures are known as tracts; each nerve is covered on the outside by a dense sheath of the epineurium. Beneath this is a layer of flat cells, the perineurium, which forms a complete sleeve around a bundle of axons.
Perineurial septae subdivide it into several bundles of fibres. Surrounding each such fibre is the endoneurium; this forms an unbroken tube from the surface of the spinal cord to the level where the axon synapses with its muscle fibres, or ends in sensory receptors. The endoneurium consists of an inner sleeve of material called the glycocalyx and an outer, meshwork of collagen fibres. Nerves are bundled and travel along with blood vessels, since the neurons of a nerve have high energy requirements. Within the endoneurium, the individual nerve fibres are surrounded by a low-protein liquid called endoneurial fluid; this acts in a similar way to the cerebrospinal fluid in the central nervous system and constitutes a blood-nerve barrier similar to the blood-brain barrier. Molecules are thereby prevented from crossing the blood into the endoneurial fluid. During the development of nerve edema from nerve irritation, the amount of endoneurial fluid may increase at the site of irritation; this increase in fluid can be visualized using magnetic resonance neurography, thus MR neurography can identify nerve irritation and/or injury.
Nerves are categorized into three groups based on the direction that signals are conducted: Afferent nerves conduct signals from sensory neurons to the central nervous system, for example from the mechanoreceptors in skin. Efferent nerves conduct signals from the central nervous system along motor neurons to their target muscles and glands. Mixed nerves contain both afferent and efferent axons, thus conduct both incoming sensory information and outgoing muscle commands in the same bundle. Nerves can be categorized into two groups based on where they connect to the central nervous system: Spinal nerves innervate much of the body, connect through the vertebral column to the spinal cord and thus to the central nervous system, they are given letter-number designations according to the vertebra through which they connect to the spinal column. Cranial nerves innervate parts of the head, connect directly to the brain, they are assigned Roman numerals from 1 to 12, although cranial nerve zero is sometimes included.
In addition, cranial nerves have descriptive names. Specific terms are used to describe their actions. A nerve that supplies information to the brain from an area of the body, or controls an action of the body is said to "innervate" that section of the body or organ. Other terms relate to whether the nerve affects the same side or opposite side of the body, to the part of the brain that supplies it. Nerve growth ends in adolescence, but can be re-stimulated with a molecular mechanism known as "Notch signaling". If the axons of a neuron are damaged, as long as the cell body of the neuron is not damaged, the axons would regenerate and remake the synaptic connections with neurons with the help of guidepost cells; this is referred to as neuroregeneration. The nerve begins the process by destroying the nerve distal to the site of injury allowing Schwann cells, basal lamina, the neurilemma near the injury to begin producing a regeneration tube. Nerve growth factors are produced causing many nerve sprouts to bud.
When one of the growth processes finds the regeneration tube, it begins to grow towards its original destination guided the entire time by the regeneration tube. Nerve regeneration is slow and can take up to several months to complete. While this process does repair some nerves, there will still be some functional deficit as the repairs are not perfect. A nerve conveys information in the form of electrochemical impulses carried by the individual neurons that make up the nerve; these impulses are fast, with some myelinated neurons conducting at speeds up to 120 m/s. The impulses travel from one neuron to another by crossing a synapse, the message is converted from electrical to chemical and back to electrical. Nerves can be categorized into two groups based on function: An afferent nerve fiber conducts sensory information from a sensory neuron to the central nervous system, where the information is processed. Bundles of fibres or axons, in the peripheral nervous system are called nerves, bundles of afferent fibers are known as sensory nerves.
An efferent nerve fiber conducts signals from a motor neuron in the central nervous system to muscles. Bundles of these fibres are known as efferent nerves; the nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. In vertebrates it consists of two main par
Lesional demyelinations of the central nervous system
Multiple sclerosis and other demyelinating diseases of the central nervous system produce lesions and glial scars or scleroses. They present different shapes and histological findings according to the underlying condition that produces them. Demyelinating diseases are traditionally classified in two kinds: demyelinating myelinoclastic diseases and demyelinating leukodystrophic diseases. In the first group a normal and healthy myelin is destroyed by a toxic, chemical or autoimmune substance. In the second group, myelin is degenerates; the second group was denominated dysmyelinating diseases by Poser Therefore, since Poser demyelinating diseases refers to the myelinoclastic part. Demyelinating diseases of the CNS can be classified according to their pathogenesis into five non-exclusing categories: demyelination due to inflammatory processes, viral demyelination, demyelination caused by acquired metabolic derangements, hypoxic–ischaemic forms of demyelination and demyelination caused by focal compression.
The four non-inflammatory possibilities are: viral demyelination, metabolic demyelination, hypoxic–ischaemic forms of demyelination and, demyelination caused by focal compression. All these four types of demyelination are non-inflammatory and different to MS if some leukoencephalopathies can produce similar lesions Typical lesions are similar to those of MS, but there are four kinds of atypical inflammatory demyelinating lesions: Ring-like, Balo-like, diffusely-infiltrating lesions; the list of the diseases that produce CNS demyelinating lesions is not complete, but it includes: Standard multiple sclerosis, the most known and extended variant. Optic-spinal MS variants and Devic's disease, or Neuromyelitis optica considered a separate disease Acute disseminated encephalomyelitis or ADEM, a related disorder in which a known virus or vaccine triggers autoimmunity against myelin. Acute hemorrhagic leukoencephalitis a variant of Acute disseminated encephalomyelitis Balo concentric sclerosis, an unusual presentation of plaques forming concentrenic circles, which can sometimes get better spontaneously.
Schilder disease or diffuse myelinoclastic sclerosis: is a rare disease that presents clinically as a pseudotumoural demyelinating lesion. Marburg multiple sclerosis, an aggressive form known as malignant, fulminant or acute MS. Tumefactive Multiple sclerosis: lesions whose size is more than 2 cm, with mass effect, oedema and/or ring enhancement AntiMOG associated encephalomyelitis: Lesions similar to ADEM sometimes and to NMO some others, it is not normal, but can appear like MS with biopsy. These cases resemble; the demyelinating lesion presents T-cells and macrophages around blood vessels, with preservation of oligodendrocytes and signs of complement system activation. A special characteristic that makes a difference between MS and the several kinds of ADEM is the structure of the lesions, being perivenous in ADEM and showing a confluence around veins in MS. Given that ADEM can be multiphase sometimes and MS can appear in children, this characteristic is considered as the line that separates both conditions.
The most typical of perivenous demyelination is ADEM ADEM can present plaque-like lesions which are indistinguishable from MS Nevertheless, ADEM White Matter appears intact under Magnetization Transfer MRI, while MS shows problems. Besides ADEM does not present "black holes" under MRI and lesions develop around veins instead of the more relaxed rule for MS As with MS, several patterns have been described inside NMO, but they are heterogeneus inside the same individual, reflecting stages in the lesion evolution: The first reflects complement deposition at the surface of astrocytes, associated with granulocyte infiltration and astrocyte necrosis demyelination, global tissue destruction and the formation of cystic, necrotic lesions. Wallerian degeneration in lesion-related tracts. Around active NMO lesions AQP4 may selectively be lost in the absence of aquaporin 1 loss or other structural damage. Another pattern is characterized by clasmatodendrosis of astrocytes, defined by cytoplasmic swelling and vacuolation and dissolution of their processes and nuclear alterations resembling apoptosis, associated with internalization of AQP4 and AQP1 and astrocyte apoptosis in the absence of complement activation.
Such lesions give rise to extensive astrocyte loss, which may occur in part in the absence of any other tissue injury, such as demyelination or axonal degeneration. Lesions with a variable degree of astrocyte clasmatodendrosis are found, which show plaque-like primary demyelination, associated with oligodendrocyte apoptosis, but with preservation of axons. Early active demyelinating NMO lesions may show complement within macrophages and oligodendrocyte apoptosis associated with a selective loss of minor myelin proteins, in addition to typical NMO features in a subset of active demyelinating NMO lesions The demyelination around a vein is called "plaque". In MS plaques are reported to appear by coalescence of several confluent smaller demyelinations. MS lesions are small ovoid lesions, less than 2 cm. long, oriented perpendicular to the long axis of the brain's ventricles Often they are disposed surrounding a vein Active and pre-active lesions appear as hyperintense areas under T2-weighted MRI.
Pre-active lesion here refers to lesions localized in the normal appearin
A sauna, or sudatory, is a small room or building designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these facilities. The steam and high heat make the bathers perspire. Infrared therapy is referred to as a type of sauna, but according to the Finnish sauna organizations, infrared is not a sauna. Borrowed from the early Proto-Germanic *stakna- whose descendants include English stack, the word sauna is an ancient Finnish word referring to the traditional Finnish bath and to the bathhouse itself. In Finnic languages other than Finnish and Estonian and cognates do not mean a building or space built for bathing, it can mean a small cabin or cottage, such as a cabin for a fisherman. The sauna known in the western world today originates from Northern Europe. In Finland, there are built-in saunas in every house; the oldest known saunas in Finland were made from pits dug in a slope in the ground and used as dwellings in winter. The sauna featured a fireplace.
Water was thrown on the hot stones to give a sensation of increased heat. This would raise the apparent temperature so high; the first Finnish saunas are what nowadays are called savusaunas. These differed from present-day saunas in that they were heated by heating a pile of rocks called kiuas by burning large amounts of wood about 6 to 8 hours, letting the smoke out before enjoying the löyly, or sauna heat. A properly heated "savusauna" gives heat up to 12 hours. Saunas were common all over Europe during the Middle Ages. Due to the spread of syphilis and subsequent scare of the disease in the 1500s, the sauna culture died out on most of the continent. Finland was a notable exception to this due to the epidemic not taking a strong hold in the area, a key reason why the sauna culture is nowadays perceived as Finnish; as a result of the Industrial Revolution, the sauna evolved to use a metal woodstove, or kiuas, with a chimney. Air temperatures averaged around 75–100 °C but sometimes exceeded 110 °C in a traditional Finnish sauna.
When the Finns migrated to other areas of the globe they brought their sauna designs and traditions with them. This led to further evolution of the sauna, including the electric sauna stove, introduced in 1938 by Metos Ltd in Vaasa. Although the culture of sauna nowadays is more or less related to Finnish culture, the evolution of sauna happened around the same time both in Finland and the Baltic countries sharing the same meaning and importance of sauna in daily life, shared still to this day; the Sauna became popular in Scandinavia and the German speaking regions of Europe after the Second World War. German soldiers had got to know the Finnish saunas during their fight against the Soviet Union on the Soviet-Finnish front of WWII, where they fought on the same side. Finnish hygiene depended so on saunas, that they had built saunas not only in mobile tents but in bunkers. After the war, the German soldiers brought the habit back to Germany and Austria, where it became popular in the second half of the 20th century.
The German sauna culture became popular in neighbouring countries such as Switzerland, the Netherlands and Luxembourg. Archaeological sites in Greenland and Newfoundland have uncovered structures similar to traditional Scandinavian farm saunas, some with bathing platforms and "enormous quantities of badly scorched stones"; the traditional Korean sauna, called the hanjeungmak, is a domed structure constructed of stone, first mentioned in the Sejong Sillok of the Annals of the Joseon Dynasty in the 15th century. Supported by Sejong the Great, the hanjeungmak was touted for its health benefits and used to treat illnesses. In the early 15th century, Buddhist monks maintained hanjeungmak clinics, called hanjeungso, to treat sick poor people. Korean sauna culture and kiln saunas are still popular today, Korean saunas are ubiquitous. Under many circumstances, temperatures approaching and exceeding 100 °C would be intolerable and fatal if exposed to long periods of time. Saunas overcome this problem by controlling the humidity.
The hottest Finnish saunas have low humidity levels in which steam is generated by pouring water on the hot stones. This allows air temperatures that could boil water to be tolerated and enjoyed for longer periods of time. Steam baths, such as the Turkish bath, where the humidity approaches 100%, will be set to a much lower temperature of around 40 °C to compensate; the "wet heat" would cause scalding. In a typical Finnish sauna, the temperature of the air, the room and the benches is above the dew point when water is thrown on the hot stones and vaporized. Thus, they remain dry. In contrast, the sauna bathers are at about 38 °C, below the dew point, so that water is condensed on the bathers' skin; this process makes the steam feel hot. Finer control over the temperature experienced can be achieved by choosing a higher level bench for those wishing a hotter experience or a lower level bench for a more moderate temperature. A good sauna has a small temperature gradient between the various seating levels.
Doors need to be kept closed and used to maintain the temperature inside. Some North American, Western European, Japanese and South African public sport centres and gyms include sauna facilities, they may be present at public and private swimming pool
Multiple sclerosis signs and symptoms
Multiple sclerosis can cause a variety of symptoms: changes in sensation, muscle weakness, abnormal muscle spasms, or difficulty moving. The main clinical measure in progression of the disability and severity of the symptoms is the Expanded Disability Status Scale or EDSS; the initial attacks are transient and self-limited. They do not prompt a health care visit and sometimes are only identified in retrospect once the diagnosis has been made after further attacks; the most common initial symptoms reported are: changes in sensation in the arms, legs or face, complete or partial vision loss, double vision, unsteadiness when walking, balance problems. Fifteen percent of individuals have multiple symptoms. Bladder problems appear in 70–80% of people with multiple sclerosis and they have an important effect both on hygiene habits and social activity. Bladder problems are related with high levels of disability and pyramidal signs in lower limbs; the most common problems are an increase in frequency and urgency but difficulties to begin urination, leaking, sensation of incomplete urination, retention appear.
When retention occurs secondary urinary infections are common. There are many cortical and subcortical structures implicated in urination and MS lesions in various central nervous system structures can cause these kinds of symptoms. Treatment objectives are the alleviation of symptoms of urinary dysfunction, treatment of urinary infections, reduction of complicating factors and the preservation of renal function. Treatments can be classified in two main subtypes: non-pharmacological. Pharmacological treatments vary depending on the origin or type of dysfunction and some examples of the medications used are:alfuzosin for retention,trospium and flavoxate for urgency and incontinency, desmopressin for nocturia. Non pharmacological treatments involve the use of pelvic floor muscle training, biofeedback, bladder retraining, sometimes intermittent catheterization. Bowel problems affect around 70% of patients, with around 50% of patients suffering from constipation and up to 30% from fecal incontinence.
Cause of bowel impairments in MS patients is either a reduced gut motility or an impairment in neurological control of defecation. The former is related to immobility or secondary effects from drugs used in the treatment of the disease. Pain or problems with defecation can be helped with a diet change which includes among other changes an increased fluid intake, oral laxatives or suppositories and enemas when habit changes and oral measures are not enough to control the problems; some of the most common deficits affect recent memory, processing speed, visual-spatial abilities and executive function. Symptoms related to cognition include emotional instability and fatigue including neurological fatigue. A form of cognitive disarray is experienced, where specific cognitive processes may remain unaffected, but cognitive processes as a whole are impaired. Cognitive deficits are independent of physical disability and can occur in the absence of neurological dysfunction. Severe impairment is a major predictor of a low quality of life, caregiver distress, difficulty in driving.
Cognitive impairments occur in about 40 to 60 percent of patients with multiple sclerosis, with the lowest percentages from community-based studies and the highest ones from hospital-based. Impairments may be present at the beginning of the disease. Probable multiple sclerosis sufferers, meaning after a first attack but before a secondary confirmatory one, have up to 50 percent of patients with impairment at onset. Dementia occurs in only five percent of patients. Measures of tissue atrophy are well correlated with, predict, cognitive dysfunction. Neuropsychological outcomes are correlated with linear measures of sub-cortical atrophy. Cognitive impairment is the result of not only tissue damage, but tissue repair and adaptive functional reorganization. Neuropsychological testing is important for determining the extent of cognitive deficits. Neuropsychological rehabilitation may help to reverse or decrease the cognitive deficits although studies on the issue have been of low quality. Acetylcholinesterase inhibitors are used to treat Alzheimer's disease related dementia and so are thought to have potential in treating the cognitive deficits in multiple sclerosis.
They have been found to be effective in preliminary clinical trials. Emotional symptoms are common and are thought to be both a normal response to having a debilitating disease and the result of damage to specific areas of the central nervous system that generate and control emotions. Clinical depression is the most common neuropsychiatric condition: lifetime depression prevalence rates of 40–50% and 12-month prevalence rates around 20% have been reported for samples of people with MS. Brain imaging studies trying to relate depression to lesions in certa
A mobility aid is a device designed to assist walking or otherwise improve the mobility of people with a mobility impairment. There are various walking aids which can help people with impaired ability to walk and wheelchairs or mobility scooters for more severe disability or longer journeys which would otherwise be undertaken on foot. For people who are blind or visually impaired the white cane and guide dog have a long history of use. Other aids can transfer within a building or where there are changes of level. Traditionally the phrase "mobility aid" has applied to low technology mechanical devices; the term appears in government documents, for example dealing with tax concessions of various kinds. It refers to those devices whose use enables a freedom of movement similar to that of unassisted walking or standing up from a chair. Technical advances can be expected to increase the scope of these devices for example by use of sensors and audio or tactile feedback. Walking aids include assistive canes and walkers.
As appropriate to the needs of the individual user, these devices help to maintain upright ambulation by providing any or all of: improved stability, reduced lower-limb loading and generating movement. Improved stability By providing additional points of contact the walking aid provides both additional support and a wider range of stable centre of gravity positioning. Reduced lower-limb loading By directing load through the arms and the walking aid, lower impact and static forces are transmitted through the affected limbs. Generating Movement The walking aid and arms can substitute for the muscles and joints of the spine, pelvis and/or legs in the generation of dynamic forces during walking; the cane or walking stick is the simplest form of walking aid. It is held in the transmits loads to the floor through a shaft; the load which can be applied through a cane is transmitted through the user's hands and wrists and limited by these. A crutch transmits loads to the ground through a shaft, but has two points of contact with the arm, at the hand and either below the elbow or below the armpit.
This allows greater loads to be exerted through a crutch in comparison with a cane. Devices on the market today include a number of combinations for canes and forearm crutches; these crutches have bands that encircle the upper arms and handles for the patient to hold and rest their hands to support the body weight. The forearm crutch gives a user the support of the cane but with additional forearm support to assist in mobility; the forearm portion helps increase balance, lateral stability and reduces the load on the wrist. A walker is the most stable walking aid and consists of a freestanding metal framework with three or more points of contact which the user places in front of them and grips during movement; the points of contact may be either fixed rubber ferrules as with crutches and canes, or wheels, or a combination of both. Wheeled walkers are known as rollators. Many of these walkers come with an inbuilt seat so that the user may rest during use and with metal pouches to carry personal belongings.
A walker cane hybrid was introduced in 2012 designed to bridge the gap between a walker. The hybrid has two legs, it can be used with two hands in front of the user, similar to a walker, provides an increased level of support compared with a cane. It can be adjusted for use with either one or two hands, at the front and at the side, as well as a stair climbing assistant; the hybrid is not designed to replace a walker which has four legs and provides 4-way support using both hands. Another device to assist walking that has entered the market in recent years is the gait trainer; this is a mobility aid, more supportive than the standard walker. It offers support that assists weight-bearing and balance; the accessories or product parts that attach to the product frame provide unweighting support and postural alignment to enable walking practice. The Walk Aid Scooter allows a user with normal balance and foot, knee or hip conditions to unload the lower extremities; the two-wheeled scooter has a bicycle-type seat and handlebars, is manually propelled with one or both feet like a balance bicycle.
This walking aid scooter provides more support than a cane and is lighter,less bulky and easier to propel than a wheelchair. Wheelchairs and mobility scooters substitute for walking by providing a wheeled device on which the user sits. Wheelchairs may be either electrically powered. Mobility scooters are electrically powered. Wheelchairs and Scooters are recommended for any individual due to significant mobility/balance impairment. A Registered Occupational Therapist or Physiotherapist are able to provide object and clinical testing to ensure proper and safe device recommendations. A stairlift wheelchairs up and down stairs. Sometimes special purpose lifts are provided elsewhere to facilitate access for the disabled, for example at entrances to raised bus stops in Curitiba, Brazil. A wheelchair lift is designed to carry the user and the wheelchair; this can either be through floor. Mobility aids may include adaptive technology such as sling lifts or other patient transfer devices that help transfer users between beds and chairs or lift chairs, transfer or convertible chairs.
Knee scooters help some users. Michael W. Whittle, R (