TABLE 1.
Characteristics of papers included
| Author | Design | Sample | Language impairments found | Associated mechanisms | Severity of language impairment | Impact of impairments | Intervention study? | QualSyst (%) |
|---|---|---|---|---|---|---|---|---|
| Parkinson disease dementia (PDD) | ||||||||
| Cummings et al. (1988) | Case‐control | Sixteen people with PDD (compared to 35 PD without dementia) | Reduced phrase length, information content, phrase repetition, comprehension, and naming (compared to PD without dementia) | NR | NR | NR | NO | 60 |
| Piat et al. (1999) | Case‐control | Twenty people with PDD (compared to 59 healthy control and 57 with PD) | PDD impaired in fluency tasks (particularly action naming) | NR | NR | NR | NO | 93 |
| Ash et al. (2017) | Case‐control | Three PDD/five DLB (among a group of 23 people with PDD) | Slower speech rate, higher mean of length of utterance and poorer report of content | No relationship found between language function and changes in overall cognitive or motor function | NR | NR | NO | 54 |
| Frank et al. (1996) | Case‐control | Twelve PDD (part of a group of 42 individuals with dementia due to AD, HD, and PD and age‐matched controls) | Decline in confrontation naming in moderate dementia PD group | Naming may be reduced due to reduced access to semantic referents | NR | NR | NO | 45 |
| Magdalinou et al. (2018) | Case‐control | Eighteen people living with PDD (and seven PSP, four CBS) | Reduced verbal fluency and sentence generation (in the three patient groups) | No associated language deficits: executive function performance appeared to play a role; authors suggest a specific effect on verbal output of dopaminergic stimulation | NR | NR | NO | 66 |
| Azuma et al. (1997) | Case‐control | Fifteen PDD (also 99 PD and 46 healthy controls) | Reduced semantic fluency; some reduction in letter fluency and fluency for proper names in the PDD group | NR | NR | NR | NO | 69 |
| Bayles et al. (1993) | Case‐control | Twenty people with PDD (among a group of 88 with PD, 21 AD, and 43 healthy controls) | Reduced semantic and letter fluency in the PDD group (scoring similar to the AD group) | NR | NR | NR | NO | 83 |
| Lewis et al. (1998) | Case‐control | Eight PDD (among a group of 20 PD) | Reduced naming, word definition, ability to interpret ambiguity and figurative language, sentence construction, and semantic verbal fluency compared to PD and normal score in cognitive functioning | NR | NR | NR | NO | 83 |
| Suhr et al. (1998) | Case‐control | Twenty‐six PDD with mild dementia (compared to 31 AD and 14 HD) | Reduced semantic and verbal fluency; less repetition errors in PDD group | NR | NR | NR | NO | 83 |
| Dementia with Lewy bodies/PDD | ||||||||
| Ash et al. (2012) | Case‐control | Fourteen DLB/PDD (out of a group including 21 patients with PD and 21 healthy controls) | Speech rate reduced (wpm) in half compared to seniors and significantly reduced compared to PD. More silent pauses and difficulties in grammatical production | Reduced speech rate correlated with measures of between‐utterance pauses, executive function and grammatical comprehension (frontal lobe mediated) | NR | NR | NO | 80 |
| Ash et al. (2012)b | Case‐control | Twenty‐nine DLB/PDD (compared to 26 healthy controls) | Deficit in both narrative comprehension and narrative expression | Deficits partially due to material‐neutral deficit in organizational executive resources (correlated with prefrontal cortical atrophy) | NR | NR | NO | 79 |
| Ash et al. (2011) | Case‐control | Fourteen DLB/PDD (compared to 18 PD) | Significant narrative production deficit: impairment in connecting one scene to the next and poor ability to maintain the theme | Deficit related to impairment on measures of executive function and speech fluency | NR | NR | NO | 73 |
| Grossman et al. (2012) | Case‐control | Seventeen DLB/PDD (compared to 26 PD and 19 healthy controls) | Sentence processing deficit for syntactic ambiguities | Deficit correlates with impairment in working memory | NR | NR | NO | 73 |
| Gross et al. (2012) | Case‐control | Eight PDD/nine DLB (compared to 16 PD) | Impaired sentence processing | Increased difficulty processing sentences with increase working memory demands | NR | NR | NO | 73 |
| Gross et al. (2013) | Case‐control | Twelve DLB/PDD (compared to 30 PD and 12 healthy controls) | Impaired script comprehension | Deficits associated to executive impairment | NR | NR | NO | 73 |
| Grossman et al. (2017) | Case‐control | Fourteen PDD/12 DLB (compared to 30 PD) | Difficulty appreciating narrative organization | Associated with frontal grey matter atrophy | NR | NR | NO | 67 |
| Atypical parkinsonisms PSP and CBS | ||||||||
| Santos‐Santos et al. (2016) | Cohort (longitudinal) | Five PSP/nine CBS (and 10 controls) | Both groups showed impairment in verbal fluency, naming and sentence comprehension; fewer words per minute; greater syntactical errors; reduced proportion of words in sentences. CBS but not PSP produced fewer narrative words than controls. Worsening in longitudinal assessment without new differences between groups | Phonetic and syntactic levels affected | NR | NR | NO | 100 |
| Rosser and Hodges (1994) | Case‐control | Ten PSP (and 10 with AD, 10 with HD) | Impaired fluency: letter fluency more impaired than category fluency | Poorer performances in the PSP group were associated to initiation and retrieval problems secondary to disruption in frontostriatal circuits | NR | NR | NO | 79 |
| Lebrun (1986) | Case study | One PSP | Reduced fluency (apart from voice and articulation deficits) | NR | NR | NR | NO | 100 |
| Podoll et al. (1991) | Cross‐sectional | Six PSP | High rate of self‐correction and errors in object naming (errors referring to visually similar objects) | Visual processing defect/misperception likely related to naming errors as no word‐finding difficulty was evident (indicated by word‐finding pauses, or semantic paraphasias) | NR | NR | NO | 83 |
| Robinson et al. (2006) | Case report | One PSP | Dynamic aphasia. Propositional language impaired (preserved naming, repetition and comprehension) | Impairment interpreted as being underpinned by a deficit in the generation of a fluent sequence of novel thought in discourse generation | NR | NR | NO | 70 |
| Barker et al. (2018) | Case‐control | Five PSP (compared to a group of 30 controls, three AD and two svFTD) | Four PSP showed initial periods of responding followed by periods of poorer performance for both tasks of verbal fluency and spontaneous speech | Decreased energization, defined as the attentional process of initiating and sustaining a response over time | NR | NR | NO | 100 |
| Robinson et al. (2015) | Case report experimental | One PSP | Dynamic aphasia | Aphasia not underpinned by a language‐specific deficit in selection or planning, but by a domain‐general deficit in fluent sequencing of novel thoughts | NR | NR | NO | 100 |
| Boeve et al. (2003) | Case report | One PSP | Initial anomia, paragrammatism, verbal hesitancy and slowly produced speech that evolved to full non‐fluent aphasia over time | NR | NR | NR | NO | 100 |
| Esmonde et al. (1996) | Case series | Three PSP | Dynamic aphasia | Impairment in planning and initiating language output; impairment in letter and category fluency pointed toward a deficit in initiation and retrieval processes | NR | NR | NO | 100 |
| Roher et al. (2010) | Cross‐sectional | Four PSP | Non‐fluent aphasia characterized by marked reduction in propositional speech, fewer speech errors | NR | NR | NR | NO | 75 |
| Daniele et al. (2013) | Case‐control | Ten PSP (and 10 healthy controls) | Poorer verbs/actions compared to nouns/objects in several lexical‐semantic tasks: confrontation naming, auditory and visual word‐picture matching | Deficits in the comprehension of action‐verbs from a specific semantic impairment in the category of actions | NR | NR | NO | 100 |
| Josephs et al. (2005) | case series | Four PSP with apraxia of speech | C1–Comprehension: mildly impaired. Expression: poor letter fluency. Agrammatism and semantic errors (non‐fluent) C2–Expression: poor letter fluency (only participant with no obvious aphasia) C3–Expression: poor letter fluency. Agrammatism and semantic errors (non‐fluent) C4–Expression: poor letter fluency. Paragrammatism (anomic aphasia with paragramatic errors) | NR | NR | NR | NO | 100 |
| Burrell et al. (2018) | Case‐control | Twenty‐two PSP (compared to 29 PNFA and 93 healthy controls) | Language impairment was similar in PSP than in patients with non‐fluent progressive aphasia (naming, word comprehension, semantic association and syntactic comprehension) | No significant correlation between performance on the SYDBAT subtests and performance on executive or working memory tasks, suggesting not due to executive dysfunction | SYDBAT: PSP performing similar to PNFA in naming, comprehension and semantic association domains and better in repetition | NR | NO | 100 |
| Catricala et al. (2019) | Case‐control | Seventeen PSP with movement disorder presentation (compared to 21 PD and 27 healthy controls) | More than 50% showed impairment in picture naming, semantic fluency, and sentence and single word comprehension. More than 40% of PSP showed impaired non‐word repetition | Affected linguistic levels identified were phonological, lexico‐semantic, and discourse‐pragmatic | NR | NR | NO | 100 |
| Brito‐Marques et al. (2011) | case report | One CBS | Difficulties for verbal and semantic fluency | NR | NR | NR | NO | 100 |
| Troiani et al. (2011) | Case‐control | Eleven CBS (among 32 with neurodegenerative diseases and 14 healthy controls) | Impaired verbal comprehension of quantifiers | Not attributable to visuospatial processing impairment or a primary language deficit but to a specific quantifier comprehension deficit related to damage of the parietal cortex | NR | NR | NO | 73 |
| Graham et al. (2003) | Cross‐sectional | Ten CBS | Prevalent phonologic and spelling impairments (a minority of patients also showed semantic memory and naming deficits) | NR | NR | NR | NO | 100 |
| Ferrer et al. (2003) | Cross‐sectional | Three CBS | C2–loss of fluency and anomia and deficits in comprehension of complex orders C3–no description of the characteristics of language disorder C4–no description of the characteristics of language disorder | NR | NR | NR | NO | 100 |
| McMillan et al. (2006) | Case‐control | Sixteen CBS (also 23 FTD, 25 AD, and 17 healthy controls) | Quantifier comprehension is impaired in CBS, particularly for first order quantifiers (e.g., at least three flowers) | Comprehension impairment at least partially due to number knowledge impairment in CBS (not to language impairment in the verbal representation of the number or object knowledge) and partially due to working memory deficits | NR | NR | NO | 70 |
| Morgan et al. (2011) | Case‐control | Thirteen CBS, three PCA, 14 bvFTD | People with CBS and PCA showed impairment in comprehension of cardinal quantifiers. bvFTD patients showed impaired in their comprehension of logical quantifiers | CBS and PCA impairments were partially due to deficits in quantity knowledge; bvFTD impairments correlated with deficits in executive measures | NR | NR | NO | 84 |
| Levin et al. (2015) | Cross‐sectional | Thirty‐eight CBS | Sixteen with aphasia | NR | NR | NR | NO | 91 |
| Donovan et al. (2007) | Case report | One CBS | Mild aphasia with abnormal social language usage: lack of awareness of the parameters of conversational turn taking, topic cohesion, and listener feedback | The reported frontal executive dysfunction described in CBS is suggested as the underlying cause of this abnormal language usage | WAB: 89 (mild aphasia) | NR | NO | 80 |
| McMonagle et al. (2006) | Case‐control | Fifty‐five CBS: 19 with motor onset and 36 with cognitive/behavioral onset CBS (PPA and AD group control) | Aphasia | NR | WAB: 88 (mild aphasia) in the motor onset group. WAB: 66 (moderate aphasia) in the cognitive onset group | NR | NO | 91 |
| Takao et al. (2006) | Case report | One CBS | Non‐fluent aphasia | NR | NR | NR | NO | 80 |
| Gross et al. (2010) | Case‐control | Twenty CBS (eight healthy controls) | Impaired discourse, with deficits in narrative theme, global connectedness (impaired in 16/20 subjects with CBS) and reductions in local connectedness | Discourse impairment was related to higher‐order integration of visual material (the task was based on a picture story) but not basic visuoperceptual, language, or memory functions | NR | NR | NO | 80 |
| Tree & Kay (2008) | Case‐report longitudinal | One CBS | Non‐fluent aphasia | NR | NR | NR | NO | 80 |
| Kertesz et al. (2000) | Cohort (longitudinal) | Thirty‐five CBS (15 presented with motor symptoms and 20 with cognitive onset) | Twenty‐one with aphasia | NR | Measured with the WAB. The aphasia quotient ranged from 28 to 99 in the group presenting with cognitive disorders and 59 to 99 in the group presenting with movement disorders | NR | NO | 100 |
| Grossman et al. (2004) | Case‐control | Nine CBS | Naming deficits | Confrontation naming deficits correlate with lexical retrieval and also with visual‐spatial function | NR | NR | NO | 76 |
| Behavioral variant FTD | ||||||||
| Ash et al. (2019) | Case‐control | Fourteen people with bvFTD | Baseline: reduced fluency (reduced wpm but nearly free of speech errors); follow‐up: impaired dependent clause production and production of well‐formed sentences, slower speech that became simplified with disease progression | NR | NR | NR | NO | 80 |
| Cotelli et al. (2006) | Case‐control | Sixteen bvFTD, 10 PSP, 10 CBS | Action naming more impaired than object naming for all groups. The discrepancy was larger in PSP and CBS | Suggestive of involvement of action knowledge and action representations | NR | NR | NO | 69 |
| Davis et al. (2010) | Case‐control | Twenty‐two bvFTD (among a group of 20 healthy controls, 144 NPH and 15 PNFA). BvFTD and PNFA groups were analyzed together | bvFTD/PNFA showed impairment in animal and action naming fluency | NR | NR | NR | NO | 73 |
| Pakhomov et al. (2010) | Case‐control | bvFTD (N not specified; among a total of 38 with PNFA, svFTD, and lvPPA) | Impaired naming and fluency | NR | NR | NR | NO | 69 |
| Saxon et al. (2017) | Retrospective case control study | 185 people with bvFTD and 56 ALS‐FTD | Agrammatism and impaired sentences comprehension, naming, word finding difficulties in conversation, impaired comprehension and repetition, word repetition, presence of phonological errors, agrammatism, reduced speech output, verbal perseveration and echolalia | NR | NR | NR | NO | 83 |
| Snowden et al. (2019) | Case‐control | Seventy‐one bvFTD (compared to 32 svFTD) | Around 50% bvFTD showed impaired naming and 17% impaired word‐picture matching | Compared possible semantic deficit versus executive contribution as basis for naming difficulties in bvFTD. Findings support the view that anomia can arise independently of executive impairment | NR | NR | NO | 100 |
| Yunusova et al. (2015) | Case‐control | Nine bvFTD (among a group of 33 healthy controls, 85 people with ALS and nine PNFA) | Although total pause time and number of pauses were elevated when reading out loud in bvFTD, phrase duration was normal in this group | Reference to pauses being longer because of cognitive‐language impairments | NR | NR | NO | 69 |
| d'Honincthun & Pillon (2008) | Case‐report | One bvFTD | Verb naming impaired when assessed using static depictions of actions but normal when using videotaped actions or verbal stimuli | Authors make a call for caution about stimuli selection for studies | NR | NR | NO | 91 |
| Hardy et al. (2015) | Case‐control | Twenty‐four bvFTD (compared to 14 svFTD and 18 nfvPPA and 24 healthy individuals) | Deficits in noun and verb naming and single word comprehension and diminished propositional speech | Isolated linguistic components, like verbal semantics were identified (authors corrected by nonverbal executive performance) | NR | NR | NO | 69 |
| Silvery et al. (2003) | Case‐control | Seventeen bvFTD (compared to 42 AD | Impaired action naming | Noun and verb naming and the gap in between showed correlation with executive tasks | NR | NR | NO | 92 |
| Peelle et al. (2008) | Case‐control | Thirty‐two SOC/EXEC (compared to 28 PNFA and 28 svFTD) | 28% of SOC/EXEC impaired in grammatically complex sentence comprehension | Deficits were attributable to decline in executive cognitive resources | NR | NR | NO | 62 |
| Grossman et al. (2005) | Case‐control | Eight FTD with executive deficits (compared to five PNFA and three svFTD) | Sentence comprehension difficulties | Correlation with measures of working memory, planning, and inhibition control; speculation that a material‐neutral executive resources deficit not dedicated to grammatical processing may play a role in the sentence comprehension deficit | NR | NR | NO | 62 |
| Peelle et al. (2007) | Case‐control | Seven SOC/EXEC (six people with PNFA and 20 healthy controls) | Difficulties processing sentences–partial sensitivity to grammatical errors but insensitivity to thematic violations | Results were consistent with impairment in the formation of a coherent thematic matrix | NR | NR | NO | 83 |
| Ash et al. (2006) | Case‐control | Twelve people with FTD SOC/EXEC | Profound difficulty organizing narratives: impaired WPM, accuracy of reported information, global connectedness, and maintenance of theme | Correlated with poor performances on measures of executive resources requiring and organized mental speech | NR | NR | NO | 77 |
| Cotelli et al. (2007) | Case‐control | Nine bvFTD, 15 PSP, 11 CBS (compared to 4 svFTD, 10 AD, and 10 healthy controls) | Syntactic knowledge impairment found in CBS but not PSP or bvFTD | NR | Performed within normal range in Aachener Aphasia Test | NR | NO | 75 |
| Early onset AD | ||||||||
| Imamura et la. (1998) | Cross‐sectional | N: 150 AD (using age at onset as a continuous variable) | EOAD worse on word comprehension and sequential commands and rapid decline of naming ability | NR | Measured with WAB. The earlier the age at onset the lower the AQ on the WAB | NR | NO | 83 |
| Sa et al. (2012) | Case‐control | 109 EOAD (compared to 171 LOAD) | No language impairment described | NR | NR | NR | NO | 72 |
| Borges et l. (2018) | Case‐report | One person with EOAD | Marked difficulties in comprehension and sentence repetition that progressed to global aphasia | NR | Global aphasia 3 years after symptoms onset | NR | NO | 30 |
| Selnes et la. (1988) | Case‐control | Sixty‐one EOAD (compared to 72 LOAD) | No language impairment and no differences in language dysfunction between groups found | NR | NR | NR | NO | 77 |
| Posterior cortical atrophy | ||||||||
| Fitzpatrick et al. (2019) | Case report | One PCA | Logopenic aphasia | NR | NR | NR | NO | 40 |
| Steeb et al. (2018) | Case‐report longitudinal | One PCA | Baseline: impaired fluency for nouns; follow‐up: impaired fluency for nouns and verbs | NR | NR | NR | NO | 80 |
| Shebani et al. (2017) | Case‐control | Ten PCA (compared to one svFTD) | Greater deficits on word processing than for spatial prepositions in PCA (e.g., under, through) | NR | NR | NR | NO | 75 |
| Crutch et al. (2013) | Case‐control | 15 PCA (compared to 7 LPA and 18 healthy individuals) | Impairment across all language domains, more prominent for anomia, reduced fluency and speech rate. PCA performed better than LPA on tasks of comprehension and spontaneous speech | NR | NR | NR | NO | 69 |
| Magnin et al. (2012) | Case‐control | Nine PCA | 8/9 PCA participants showed a logopenic profile, with anomia, reductions in fluency, and a length‐dependent deficit | NR | NR | NR | NO | 83 |
| Suárez‐González et al. (2019) | Case‐control | Eight PCA (compared to 21 AD and 18 healthy controls) | Impaired comprehension of measurement units (e.g., grams) | NR | NR | NR | NO | 69 |
| Motor neuron disease with FTD | ||||||||
| Bak et al. (2001) | Cross‐sectional | 2/6 MND‐dementia‐aphasia | In one case, severe reduction in spontaneous speech, semantic paraphasia, communicating in a “telegraphic” way. The other case shows echolalia and naming inaccuracies. | NR | NR | NR | NO | 73 |
| Rakowic & Hodges (1998) | Case‐control | Three MND‐FTD (compared to two MND with aphasia and 13 MND) | Only 2/3 patients were formally assessed–deficits on verbal fluency, picture naming, word‐picture matching, semantics, and grammar were found | NR | NR | NR | NO | 79 |
| Bak & Hodges (2004) | Cross‐sectional | Seven MND‐dementia | Poverty of spontaneous speech, severe impairment on syntactic comprehension, a consistently large impairment noticed for verbs (both naming and comprehension) | NR | described as severe | NR | NO | 81 |
| Kamminga et al. (2016) | Case‐control | Fifteen FTD‐ALS (compared to 20 ALS, 27 PNFA, and 23 controls) | Impaired syntactic comprehension | NR | NR | NR | NO | 79 |
Abbreviations: AD, Alzheimer's disease; ALS, amyotrophic lateral sclerosis; AQ, aphasia quotient; bvFTD, behavioral variant frontotemporal dementia; CBS, corticobasal syndrome; DLB, dementia with Lewy bodies; EOAD, early‐onset Alzheimer's disease; FTD, frontotemporal dementia; HD, Huntington's disease; LOAD, late‐onset Alzheimer's disease; LPA, logopenic aphasia; lvPPA, language variant primary progressive aphasia; MND, motor neuron disease; nfvPPA, non‐fluent variant of primary progressive aphasia; NPH, normal pressure hydrocephalus; NO, xxxxxxxxx; NR, no reported; PCA, posterior cortical atrophy; PDD, Parkinson's disease dementia; PNFA, progressive non‐fluent aphasia; PPA, primary progressive aphasia; PSP, progressive supranuclear palsy; QualSyst, Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields; SOC/EXEC, disorder of social comportment and executive processing (this is the term used by the authors of the corresponding papers); svFTD, semantic variant frontotemporal dementia; SYDBAT, Sydney Language Battery; WAB, Western Aphasia Battery; WPM, words per minute.