through eye-tracking devices as long as the ocular mus- cles stay intact. • As the Trochlear nerve becomes affected, because eyesight is still intact, the only solution that remains for patients to communicate is the use of a Brain Controlled Interface (BCI). • Typically, the end of life is 3-5 years after initial diagnosis, but those diagnosed younger than 50 generally exceed this timeframe, if the patient survives past 5 years PLS (Pri- mary Lateral Sclerosis) would be under consideration. The disease typically follows a predictable pattern of progres- sion, with symptoms worsening over time. Some patients may progress through the stages more quickly or slowly than others, and the order of symptoms may also vary. However, understand- ing the stages of ALS can help patients and their caregivers pre- pare for the changes that may occur and make the necessary adjustments to maintain the patient's quality of life. As ALS pro- gresses individuals move through the stages of the disease at varying rates. In general, the late stage is the shortest in longev- ity but that is not always a standard expectation. CURRENT SGD (SPEECH GENERATION DEVICES) ACCESS METHODS FOR PATIENTS WITH ALS The need for SGD technologies occurs early in the disease due to emergent speech disabilities. Initially, ALS patients may face intelligibility issues for their speech, and subsequently, they may have no functional speech and require speech-generating devices to communicate at all. Dysarthria occurs in more than 80% of ALS patients and is seen earlier in those with bulbar on- set who may become anarthric after a few months of disease on- set. Approximately 80% of ALS patients utilize some form of SGD device, and on average, rely upon it for 2-3 years. Most move from a direct select access (i.e., typing) to possibly a finger drag typing style and then usually end up using eye-tracking as their main access method. Eye tracking computer systems (ETCS) can allow cursor control by eye movement and represent a current standard of care. As stated previously, eye movements can be less fatiguing and at later stages of the disease can be the only remaining volitional movements that allow patients to commu- nicate. Currently, clients with ALS use the following access methods to their Speech Generating Devices (SGD); touchscreen, switch interfaces, eye tracking and/or head mouse, these access meth- ods have been used with limited success with many late-stage pALS. In isolation and at the appropriate stage, access can be successful, but as the disease progresses, the ability to transition from access method to access method is always needed. The largest void of AAC (Augmentative and Alternative Com- munication) access for people with ALS is at the late stage or closer to the end of life. At this stage, even eye tracking becomes difficult if not impossible due to the disease progression and/or
ocular comorbidities. In a study looking at ALS patients and ab- normal eye movements anywhere from 60-70% of ALS patients were reported to have ocular issues. (Eye Movement Abnormali- ties in Amyotrophic Lateral Sclerosis in a Tunisian Cohort) Because the eyes and forehead are bilaterally innervated, they are usually the last reliable access method for people with ALS. In short, bilateral innervation means that relatively equal distri- butions of right and left-brain hemisphere innervation govern the function of a specific facial part (such as the eye muscles). The 7 extraocular muscles, even though bilaterally innervated, are small and thus fatigue quickly causing the AAC user to have false positive selections when eye tracking. Research has shown that it is reasonable that with bulbar disabilities, eye movement abnormalities should be considered (Eye Movement Abnormal- ities in ALS) and may need to be addressed with disease pro- gression. SGD ACCESS METHODS AND PROS AND CONS RELATED TO ALS
Access Method
Pros
Cons
Stage of ALS
Used in early stage of ALS
Positioning of device for access and ability to isolate their fingers causing false positive selections. Slow access to language and access, higher incident of false positive strikes. Very slow access to language. Calibration issued and positioning of device, direct sunlight washing out cameras For most ALS pa- tients the ability to maintain good head movement and/or position- ing degrades early in the disease progression
Touchscreen
Immediate access to their language/ AAC device.
Switch interface Ability to access different areas of the body depend- ing on muscle control
Used in middle and late stage of ALS
Used in mid stage and late of ALS
Eye Tracking
Eyes remain intact until late stage of ALS but will eventually fail as an access point Allows for direct select access with gross movement of head move- ment
Head Mouse
Used in early to middle stage of ALS
WHAT IS A BRAIN CONTROLLED INTERFACE (BCI)? In short, a Brain-Computer Interface (BCI) is a system that enables communication and control between the brain and an external device, such as a computer, without requiring any phys- ical movement or action. BCI technology typically involves the use of sensors (electroencephalogram = EEG’s) to detect and in- terpret neural activity, which is then translated into commands
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