The effects of Multiple Sclerosis can cause disruption to cognitive processing, motor speech, language, as well as speech fluency, depending on the location of MS lesions. These symptoms may be experienced as "moving targets" in the case of relapsing-remitting MS, due to fluctuations in fatigue severity, or as a function of intervals between disease-modifying therapies. MS is more likely to occur in a younger population than many other neurodegenerative diseases and thus communication and cognitive effects can interfere with work or school-related activities.

Speech pathology neurorehabilitation services can be a very helpful intervention in managing cognitive and communication symptoms related to MS, including adapting rehabilitative approaches and tools according to the variable nature of symptoms. Services may involve direct rehabilitation of neurological deficits that occur from MS lesions to achieve underlying improvement of the function, as well as the use of adaptive approaches to address chronic symptoms. Interventions may include cognitive fatigue management strategies to work around MS related fatigue impacting the ability to concentrate and execute complex cognitive activities such as problem solving and activities requiring intense cognitive processing.

ALS and related motor neuron diseases (e.g., PLS) cause progressive loss of speech function across the course of disease due to weakness, spasticity, and atrophy of speech musculature. Early establishment of care with Speech Pathology is vital to staying ahead of significant changes in speech, to maximize intelligibility and communication in early and mid stages of the disease and to put interventions in place for later disease stages before augmentative and alternative communication systems are needed. Services during early disease stages include extensive education and counseling regarding navigating communication changes associated with disease progression and measurements of speech rate which is a key measurement to predict medical decision making for swallowing and alternative communication needs later in the course of disease. During mid-disease stages, services may include compensatory strategy training to navigate breakdowns in the extent to which speech is understood and utilizing devices such as speech amplifiers or other technologies, depending on the person's dexterity, to supplement spoken messages. As speech difficulty becomes more severe, speech therapy serves to help the individual transition to the use of speech generating devices, often including the use of eye gaze, depending upon the status of dexterity and movement of the rest of the body.

Primary Progressive Aphasia (PPA) involves the progressive atrophy and degeneration of left hemisphere brain regions that are involved in language. It most commonly occurs in older adults and is a rare, but increasingly recognized condition with significantly more research within the last 2 decades. There are 3 primary subtypes of PPA (logopenic, nonfluent, and semantic variants) that are associated with the specific nature of language difficulty, as well as a rare related disorder, Primary Progressive Apraxia of Speech (PPAOS) which may or may not co-occur with PPA-nonfluent variant. Individuals with PPA experience the gradual loss of language function; the rate of deterioration can have some association with subtype and may differ considerably across individuals. There is no known cure for this extremely difficult disease.

Speech therapy services are paramount in the management of PPA; although loss of language functioning is progressive, speech and language therapy can slow the rate of language decline in some circumstances, and more universally, provide education and training to individuals with PPA and their care partners in navigating the progressive changes in language function. These interventions may include self-cuing strategies to retrieve words and get messages across, the use of multiple language modalities to get a message across in a different way if spoken language is "blocked", development and training of low-tech and/or high-tech communication strategies to maximize the person with aphasia's independence in communicating for aspects of their daily life as well as to navigate communication breakdowns. While speech therapy cannot reverse the progressive loss of language, it can serve a highly supportive role for individuals to learn how to live and cope with the aphasia as effectively as possible and develop "work arounds" to allow them to get messages across, in the extremely frustrating situation of knowing what you want to say but not being able to say it.

Parkinson's disease and Parkinson's-Plus syndromes (Lewy Body Dementia, Progressive Supranuclear Palsy, etc) commonly disrupt speech and cognitive functioning across the course of disease. Surgical interventions for Parkinson's disease, such as deep brain stimulation (DBS) may be extremely effective in reducing tremor but can affect speech production in both positive and negative ways. Speech disorders arising from Parkinson's disease and related disorders may include loss of speech volume, problems with clarity of speech, changes in vocal quality, and accelerations in speech causing enunciation to become "blurred". Gradual loss of speech can results in individuals becoming less and less participative in communicating with loved ones and in the community, as a result of cumulative failures to be heard or understood decreasing motivation to initiate speech. Co-occurring neuropsychiatric changes can interact with reduced initiation and participation in communication.

Individuals living with Parkinson's disease and related disorders also commonly experience gradual onset of cognitive changes, most commonly involving "executive functioning" which is an "umbrella" term for high-level brain processes of coordinating the activities of the rest of the brain; planning, organizing, putting things in order, prioritizing, decision-making, problem solving, analysis, and similar processes.

As decades of neurorehabilitation research has shown the effects of sufficiently intense exercise to be vital in managing the progression of Parkinson's symptoms, exercise for speech is also vitally important to regain and maintain improved volume and articulation. There are several effective approaches available to address problems with speech volume, articulation, rate, and voice. Cognitive rehabiitation services also are relevant to individuals living with PD, and typically includes adaptive or compensatory approaches as well as training care partners to address the specific areas of cognitive difficulty with individualized supports, aids, and strategies. This is particularly relevant for individuals with PD who are continuing to work and may more complex or demanding cognitive needs.

Multiple System Atrophy (MSA) is a rare neurodegenerative disease. It formerly was referred to as the disease entities of Shy Drager syndrome, olivopontocerebellar atrophy, and striatonigral degeneration. MSA is currently characterized as a Parkinson's-like variant (MSA-P), a cerebellar variant (MSA-C), or a mixed presentation. Speech problems are common in MSA and tend to become problematic at a faster rate than in classic Parkinson's disease. Cognitive problems may occur in either subtype but are more prevalent in MSA-P.

Similarly to other neurodegenerative diseases, individuals with MSA benefit from establishing care with a speech-language pathologist (SLP) experienced in neurorehabilitation early in the presentation of speech changes. This allows for early education, baseline speech measurement, and establishment of self-management skills to maximize the extent to which speech is understood and to capitalize upon any available benefits of practice and exercise. A schedule or set of criteria is then established for visits to address changes in speech across the course of disease and those changes are addressed according to the individual's presentation to maximize their communicative independence, success, and quality of life. Interventions may include teaching speakers to modify aspects of enunciation, rate, breathing, or other components to make speech as understandable as possible; training care partners and modifying settings to improve communication; as well as augmentative and alternative communication strategies and systems in the case of severe speech problems.

Individuals with Huntington's disease (HD) may experience progressive difficulty associated with involuntary movements affecting the voluntary and automatic aspects of control over speech, vocal, and breathing musculature. Cognitive problems are also common across the course of disease. As significant individual differences can occur in speakers with HD and evolve across the course of disease, interventions are individual-specific and are adapted according to changes in the speaker. Cognitive rehabilitation services also are beneficial to individuals living with HD, and typically include adaptive or compensatory approaches as well as training care partners to address the specific areas of cognitive difficulty with individualized supports, aids, and strategies. This is particularly relevant for individuals with HD who are continuing to work and may more complex or demanding cognitive needs. Working with other members of the individual with HD's care team is important to make cognitive strategies and resources accessible given difficulties with limb movement control or involuntary movements in the head, neck, and trunk that may make reading difficult.

Speech, language, and cognitive problems associated with several rare neurodegenerative diseases that exist are common, and can significantly impact individuals' daily activities and quality of life. Even in the case of progressive diseases in which the speech, language, and/or cognitive effects of the disease are not reversible, patients can benefit from SLP neurorehabilitation to gain small but meaningful improvements, when possible, and always to learn to navigate the communication or cognitive problem with available tools, supports, strategies, and high tech or low tech aids available. Individuals may choose to have as little or as much neurorehabilitation supports as desired according to their personal values, situations, and needs. No one approach exists for managing communication and cognitive problems associated with neurological disease, instead each person's unique circumstances are that which interventions are designed upon.