progressive Aphasia - Davis

Primary progressive aphasia (PPA)

A neurodegenerative disorder in which speech and language abilities gradually deteriorate while general cognition is relatively preserved in the early stages.

Primary progressive aphasia vs. stroke-induced aphasia

Stroke-induced aphasia often improves and then stabilizes, whereas PPA involves progressive loss of language function over time.

Why are SLPs important in PPA?

SLPs help assess and diagnose language impairments, provide treatment, introduce compensatory communication strategies, counsel individuals and families, and monitor progression.

Typical age of onset for PPA

Individuals may develop symptoms in their late 40s to early 60s, younger than the typical onset of Alzheimer’s dementia.

Primary symptom of PPA

A gradually worsening language disturbance that is the initial and most prominent impairment.

Mesulam’s original diagnostic criteria for PPA

Language impairment has a gradual onset, is the initial and primary symptom for at least the first 2 years, and remains the most prominent impairment as the disease progresses.

Gorno-Tempini et al. (2011) diagnostic criteria modification

Language impairment must be relatively isolated during the initial phases of the disease rather than specifically during the first 2 years.

What makes a language disorder inappropriate for a PPA diagnosis?

Prominent early visuospatial impairments, episodic memory deficits, or behavioral disruptions, or language deficits clearly attributable to stroke, brain tumor, traumatic brain injury, or psychiatric conditions.

Why is early PPA diagnosis important?

It allows individuals and families to plan for progressive communication changes and learn restorative and compensatory strategies before deficits become more severe.

Three recognized PPA variants

Semantic variant (svPPA), logopenic variant (lvPPA), and nonfluent variant (nfvPPA).

When are PPA subtype differences most distinct?

During the mild to moderate stages; profiles become less distinct as the disease progresses.

Historical term “focal dementia”

An older term used to describe PPA generally.

Historical term “slowly progressive aphasia”

An older term referring broadly to PPA.

Historical term “semantic dementia”

A historical term generally associated with svPPA.

Historical term “nonfluent progressive aphasia”

An older term that historically encompassed both lvPPA and nfvPPA.

Semantic variant PPA (svPPA)

A PPA subtype characterized by progressive loss of semantic knowledge, resulting in impaired word retrieval and single-word comprehension.

Core diagnostic features of svPPA

Impaired picture naming and impaired single-word comprehension.

Supporting diagnostic features of svPPA

At least three of the following: loss of object knowledge, surface dyslexia/dysgraphia, relatively preserved repetition, and intact grammar and motor speech.

Primary deficit in svPPA

Loss of core semantic knowledge.

Anomia in svPPA

Difficulty retrieving words, often associated with loss of the meaning or conceptual knowledge of the target.

Semantic paraphasia

Producing a word related in meaning to the intended word, such as saying “jellyfish” instead of “octopus.”

Circumlocution

Describing or talking around a word when unable to retrieve it; it may help individuals with svPPA communicate despite word-finding difficulties.

Loss of object knowledge

Difficulty recognizing or understanding familiar objects and their functions; as the disorder progresses, individuals may use objects inappropriately.

Surface dyslexia

Difficulty reading irregular words because the person relies on regular sound-to-letter rules rather than recognizing the word’s stored form.

Surface dysgraphia

Difficulty spelling irregular words because the person relies on regular sound-to-letter rules.

Example of surface dyslexia/dysgraphia

Reading or spelling “island” as though it followed regular sound-to-letter rules, such as “izland.”

What abilities are relatively preserved in early svPPA?

Repetition, grammatical processing, motor speech, and reading or spelling of regular words and nonwords.

How does speech change in svPPA as the disease progresses?

Language production becomes increasingly empty of meaningful content but generally remains intelligible and grammatical.

Possible behavioral changes in svPPA

Compulsive behaviors, disinhibition, personality changes, and altered eating preferences.

Brain region most affected in svPPA

The anterior temporal lobe of the language-dominant hemisphere, with broader regions potentially affected as the disease progresses.

Most likely underlying pathology of svPPA

Frontotemporal lobar degeneration with TDP-43 pathology (FTLD-TDP).

Pharmacological treatment for svPPA

No medication currently reverses the underlying neurodegeneration; medications such as SSRIs may be prescribed to manage behavioral symptoms.

Logopenic variant PPA (lvPPA)

A PPA subtype characterized by phonological processing difficulties that affect word retrieval and repetition of phrases and sentences.

Core diagnostic features of lvPPA

Difficulty retrieving single words in spontaneous speech and picture naming, plus impaired phrase and sentence repetition.

Supporting diagnostic features of lvPPA

At least three of the following: phonemic paraphasias, relatively preserved single-word comprehension and object knowledge, lack of motor speech impairments, and spared syntactic processing.

Primary deficit in lvPPA

Impaired phonological processing and phonological working memory.

Phonological working memory

The ability to temporarily maintain and manipulate speech-sound information.

Phonemic paraphasia

An error involving substitution, addition, deletion, or rearrangement of speech sounds within a word.

Example of a phonemic paraphasia

Attempting to say “candelabra” but producing an approximation such as “candelagra.”

Why do individuals with lvPPA pause frequently?

They experience difficulty retrieving words and assembling the phonemes needed to produce them.

Why is sentence repetition impaired in lvPPA?

Difficulty maintaining and processing phonological information makes it hard to repeat longer phrases and sentences accurately.

What abilities are relatively preserved in early lvPPA?

Single-word comprehension, object knowledge, motor speech, and syntactic processing.

Is frank agrammatism typical of lvPPA?

No. Speech may sound grammatically incomplete because of word-retrieval and phonological working memory difficulties rather than a primary grammatical deficit.

How can lvPPA progress?

Speech may become increasingly jargon-like, with semantic errors and invented words; comprehension, verbal memory, and episodic memory may also deteriorate.

Brain region most affected in lvPPA

The temporoparietal region of the language-dominant hemisphere.

Most likely underlying pathology of lvPPA

An atypical presentation of Alzheimer’s disease.

Possible non-language difficulty in lvPPA

Impaired simple arithmetic or math calculations due to parietal lobe involvement.

Pharmacological treatment for lvPPA

Alzheimer’s disease medications, such as cholinesterase inhibitors, may be considered, although effectiveness varies; medications may also target associated symptoms.

Nonfluent variant PPA (nfvPPA)

A PPA subtype characterized by agrammatism and/or apraxia of speech.

Core diagnostic features of nfvPPA

At least one of the following: agrammatism or apraxia of speech.

Supporting diagnostic features of nfvPPA

At least two of the following: impaired comprehension of complex syntax, relatively preserved single-word comprehension, and relatively preserved object knowledge.

Agrammatism

Impaired grammatical processing that results in short, simple utterances and omission of grammatical elements.

Telegraphic speech

Speech that contains primarily essential content words while omitting function words and grammatical markers.

Example of telegraphic speech

“Boy… store… buy food” instead of “The boy went to the store to buy food.”

Apraxia of speech (AOS)

A motor speech planning/programming disorder that affects the ability to coordinate the movements needed for speech.

Speech characteristics associated with apraxia of speech in nfvPPA

Slow, effortful, often distorted speech with reduced or abnormal prosody that may decrease intelligibility.

Dysarthria in nfvPPA

A motor speech execution disorder that may co-occur with apraxia of speech but is not itself a defining diagnostic feature.

Primary progressive apraxia of speech (PPAOS)

A progressive speech motor planning disorder that may occur without agrammatism.

Syntax comprehension in nfvPPA

Understanding complex grammatical structures is often impaired.

What abilities are relatively preserved in early nfvPPA?

Single-word comprehension and object knowledge.

Brain regions affected in nfvPPA

Frontal and insular regions of the language-dominant hemisphere, associated with grammatical processing and motor speech planning.

Underlying pathology of nfvPPA

Often associated with frontotemporal lobar degeneration, particularly tau-related or TDP-43-related pathology; the underlying cause varies.

How does nfvPPA progress?

Speech production and grammatical abilities worsen, and additional motor or cognitive impairments may emerge depending on the underlying disease.

Main deficit in svPPA

Loss of semantic knowledge.

Main deficit in lvPPA

Phonological processing and phonological working memory difficulties.

Main deficit in nfvPPA

Agrammatism and/or apraxia of speech.

Typical word comprehension in svPPA

Impaired, including difficulty understanding single words.

Typical word comprehension in lvPPA

Relatively preserved in the early stages.

Typical word comprehension in nfvPPA

Relatively preserved in the early stages.

Typical repetition in svPPA

Relatively preserved.

Typical repetition in lvPPA

Phrase and sentence repetition is impaired.

Typical speech in svPPA

Fluent and grammatical but increasingly empty of meaningful content.

Typical speech in lvPPA

Slow, with frequent word-finding pauses and phonemic errors.

Typical speech in nfvPPA

Effortful or distorted speech and/or short, grammatically simplified utterances.

Most likely underlying disease in svPPA

Frontotemporal lobar degeneration with TDP-43 pathology.

Most likely underlying disease in lvPPA

Alzheimer’s disease pathology.

Common underlying disease group in nfvPPA

Frontotemporal lobar degeneration, often involving tau or TDP-43 pathology.

Quick distinction between semantic and phonological errors

Semantic errors involve meaning-related substitutions; phonological errors involve speech sounds within a word.

How can svPPA and lvPPA both cause anomia?

svPPA affects access to or retention of semantic knowledge, whereas lvPPA affects phonological processing needed to assemble the word’s sounds.

Primary goal of PPA assessment

Identify the individual’s language strengths and deficits, determine the likely subtype, establish functional needs, and guide treatment.

Why is a comprehensive assessment necessary?

PPA subtypes can share symptoms, and the clinician must distinguish language, semantic, phonological, grammatical, motor speech, and cognitive impairments.

Case history and interview

Gather information about symptom onset, progression, daily communication, functional impact, medical history, and the individual’s priorities.

Spontaneous speech assessment

Observe fluency, word retrieval, grammatical structure, pauses, sound errors, and intelligibility during natural communication.

Confrontation naming

Asking the individual to name pictured objects; useful for identifying anomia and semantic or phonological errors.

Single-word comprehension assessment

Determines whether the individual understands spoken or written words, helping distinguish semantic loss from other language deficits.

Repetition assessment

Evaluates the ability to repeat words, phrases, and sentences; phrase and sentence repetition is particularly important when assessing lvPPA.

Object knowledge assessment

Determines whether the individual recognizes objects and understands their meanings and functions.

Semantic association tasks

Ask the individual to identify pictures or concepts that are meaningfully related.

Pyramids and Palm Trees Test (PPT)

An object-association task used to assess semantic knowledge; individuals with svPPA typically have the greatest difficulty.

Camels and Cactus Test

A semantic association test included in the Cambridge Semantic Memory Test Battery.

Northwestern Anagram Test (NAT)

Assesses syntax production by having the individual arrange written words to describe pictures without requiring overt speech.

Why is the NAT useful for individuals with motor speech impairments?

It assesses syntax without requiring the individual to produce spoken responses.

Sentence Comprehension Test (SECT)

Assesses comprehension of sentences with varying syntactic complexity using single-word responses.

Make a Sentence Test (MAST)

Assesses production of sentences with varying syntactic complexity using supplied nouns and a verb.

Why might individuals with nfvPPA struggle with the NAT and MAST?

They may have difficulty with grammatical and syntactic processing.

Sydney Language Battery (SydBat)

A PPA assessment battery that includes confrontation naming, auditory word-picture matching, semantic association, and single-word repetition.

Repeat and Point Test

A test designed to help differentiate svPPA from progressive nonfluent aphasia by assessing word repetition and picture recognition.

Progressive Aphasia Severity Scale (PASS)

Tracks severity and progression of impairments across specific speech and language domains.

Progressive Aphasia Language Scale (PALS)

Tracks progression and severity of language impairments, including articulation, grammar, word retrieval, and word comprehension.

Dynamic assessment

Evaluates how an individual responds to cues and support, helping identify residual abilities and effective strategies.