Writing errors and anosognosia in amyotrophic lateral sclerosis with dementia

Amyotrophic lateral sclerosis (ALS) with dementia (ALS-D) is known to exhibit characteristics of frontotemporal dementia. However, in clinical situations, it is often difficult to evaluate their cognitive functions because of impaired voluntary speech and physical disabilities. In order to identify characteristic and diagnostic cognitive symptoms of relatively advanced ALS-D patients, we retrospectively reviewed the clinical features of seven cases of clinically definitive ALS who had dementia, impaired voluntary speech, and physical disability. Their medical records showed that six out of seven patients made writing errors, and all of the patients demonstrated anosognosia. The writing errors consisted of paragraphia such as substitution, omission, or syntactic errors with individual differences in error types. Dissociation between kana and kanji were also observed. Anosognosia was evaluated by a self-rating scale with which the patients and the medical staff evaluated the patient's physical ability; the results indicated a large discrepancy between the evaluation by the patients and the medical staff. We emphasize that aphasic writing errors have been underestimated, particularly in ALS-D patients with impaired voluntary speech. We also reported that anosognosia was the most important and quantifiable symptom in ALS-D. The relationship between writing errors and anosognosia should be investigated further.     

Productive syntax abilities in Huntington's and Parkinson's diseases

This study examined syntactic changes in the spoken discourse of patients with Huntington's (HD) or Parkinson's disease (PD) and explored possible relationships between their syntactic changes and concomitant cognitive and motoric symptoms. Patient and control groups participated in a conversational discourse activity and completed a battery of standardized speech and cognitive tests. The HD group used shorter and fewer grammatically complete utterances than their healthy, age-matched peers, whereas there were no significant syntactic differences between PD patients and their healthy, age-matched peers or between PD and HD patients. Productive syntax abilities in HD and PD were meaningfully related to both neuropsychological and motor speech changes. These findings indicate that patients with subcortical disease, at least those with HD, may present with language production deficits and that these deficits are most likely the product of not only motor speech limitations (i.e., dysarthria) but also underlying cognitive impairments.     

Self-monitoring behavior in a case of severe auditory agnosia with aphasia

This case report describes an unusual combination of speech and language deficits secondary to bilateral infarctions in a 62-year-old woman. The patient was administered an extensive series of speech, language, and audiologic tests and was found to exhibit a fluent aphasia in which reading and writing were extremely well preserved in comparison to auditory comprehension and oral expression, and a severe auditory agnosia. In spite of her auditory processing deficits, the patient exhibited unexpected self-monitoring ability and the capacity to form acoustic images on visual tasks. The manner in which she corrected and attempted to correct her phonemic errors, while ignoring semantic errors, suggests that different mechanisms may underlie the monitoring of these errors.     

Language acquisition following hemidecortication: Linguistic superiority of the left over the right hemisphere

The language development of three 9- and 10-year-old children possessing only a right or a left hemisphere was studied. Surgical removal of one brain half antedated the beginning of speech, so each child has acquired speech and language with only one hemisphere. Different configurations of language skill have developed in the two isolated hemispheres: phonemic and semantic abilities are similarly developed but syntactic competence has been asymmetrically acquired. In relation to the left, the right brain half is deficient in understanding auditory language, especially when meaning is conveyed by syntactic diversity; detecting and correcting errors of surface syntactic structure; repeating stylistically permuted sentences; producing tag questions which match the grammatical features of a heard statement; determining sentence implication; integrating semantic and syntactic information to replace missing pronouns; and performing judgments of word interrelationships in sentences. Language development in an isolated right hemisphere, even under seizure-free conditions, results in incomplete language acquisition.     

Production deficits in aphasia: A voice-onset time analysis

An experimental study was conducted to examine phonetic and phonemic deficits in the speech production of aphasics. Subjects included four Broca's aphasics, four Conduction aphasics, five Wernicke's aphasics, one nonaphasic dysarthric patient, and four normal controls. The subjects read a list of words containing word-initial stop consonants which were subsequently measured acoustically for voice-onset time. The results showed that Broca's aphasics exhibit a more severe production disorder than Conduction aphasics who in turn exhibit a more severe disorder than Wernicke's aphasics, in accord with clinical observations. In addition, although Broca's aphasics produced both phonetic and phonemic errors, the results showed that they have a pervasive phonetic disorder which affects their correct target productions as well as the total number of phonetic errors produced. This deficit however seems to be a speech deficit rather than a low-level motor control problem. In contrast, the Wernicke's aphasics show a deficit characterized by isolated phonemic mistargeting errors. Finally, the pattern of productions for the Conduction aphasics indicates that some patients show a predominantly phonetic disorder similar to the Broca's aphasics and others show predominantly a phonemic disorder similar to the Wernicke's aphasics.     

Repetition in the transcortical aphasias

Transcortical aphasic patients were assessed on a repetition task comprised of both well-formed and deviant sentences. The patients faithfully repeated those sentences that were factually incorrect but grammatically well formed, and those sentences that were ungrammatical because of selection restriction violations. In contrast, presented with sentences featuring only minor syntactic violations (e.g., lack of number agreement), the patients spontaneously, and without awareness, resisted exact repetition; moreover, the resultant changes most often served to correct the syntactic deviations. Repetitions of sentences of this latter type also revealed a difference between the patients as a function of level of comprehension. The transcortical motor aphasic patient was influenced by semantic factors in his alterations of the minor syntactic violations, while the transcortical sensory aphasic was not. These findings are discussed in relation to the notion of autonomous syntactic processing. They are taken to suggest that syntactic facts such as number agreement are represented at a level in the processing chain that is distinct from that of semantic representation.     

On the universality of language dissolution: The case of a Turkish aphasic

The case of a Turkish aphasic suffering from motor aphasia is described. The transitional phonemic systems which could be observed in this patient in the course of speech rehabilitation are compared to the so-called “phonemic disintegration,” whereas the errors of his graphic performance are compared to the so-called “agrammatism” of Indo-European languages. It is found that there exists a strong parallelism between this agglutinative language and the inflecting Indo-European languages insofar as aphasic language dissolution is concerned.     

Bound morpheme loss errors in normal and agrammatic speech: One mechanism or two?

Loss errors involving bound morphemes in normal and agrammatic speech are examined to determine if all errors can be due to a single processing problem. It is concluded that two problems are present. First, there is a general problem with accessing bound morphemes (or forms containing bound morphemes), leading to the production of the base form. Second, there is a syntactic problem involving agreement. In agrammatism, the first problem is differentially exacerbated. Implications for normal and agrammatic speech are examined.     

Syntactic errors in speech

Speech errors can be used to examine the nature of syntactic processing in speech production. Using such evidence, Fay (1980a, 1980b) maintains that deep structure and transformations are psychologically real. However, an interactive activation model that generates surface syntactic structures directly can account for all the data. Most syntactic errors are substitutions: The target phrase structure is replaced by a semantically related structure. Blends of two syntactic structures are also common. Transformations cannot account for much of the data and are not necessary to explain any of them. While it is impossible to prove that transformations do not exist, syntactic theories that do not include transformations have the potential to be psychologically valid.     

Syntactic structure and acoustic pattern in speech perception Arthur Wingfield

The interaction of syntactic structure and acoustic pattern in perceptual segmentation of heard speech was investigated using sentences recorded with intonation patterns appropriate to their underlying structure and sentences where intonation was placed in direct conflict with the underlying structure. Speech samples were monitored through dichotic earphones with messages switched from one ear to the other either between or within major linguistic constituents. Analysis of errors in source localization and in sentence reproduction suggested a primary role of acoustic pattern in segmentation is to cue underlying syntactic structure. Two subsidiary experiments provided evidence that observed effects were related to active perceptual processing of the speech signal.     

Age-related influences on lexical selection and orthographic encoding during homophone spelling

Two experiments investigated age differences in how semantic, syntactic, and orthographic factors influence the production of homophone spelling errors in sentence contexts. Younger and older adults typed auditorily presented sentences containing homophone targets (e.g., blew) that were categorized as having a regular spelling (EW) or an irregular spelling (UE). In Experiment 1, homophones were preceded by an unrelated word, a semantic prime that was congruent with the target's meaning in the sentence (e.g., wind), or a semantic prime incongruent with the target's meaning (e.g., sky) and instead related to the competitor homophone. Experiment 2 manipulated the target's part of speech, where target and competitor homophones shared or differed in part of speech. For both age groups, significant semantic priming occurred, where homophone errors decreased following congruent semantic primes and increased following incongruent primes. However, priming only occurred when homophones shared part of speech. Further, both age groups made more errors on homophones with an irregular than a regular spelling, and this regularity effect was smaller for older adults when homophones shared part of speech. Contrary to many spoken production tasks, older adults made fewer errors overall than younger adults. These findings demonstrate age preservation in lexical selection but age differences in orthographic encoding, resulting in older adults producing fewer errors because of reduced activation to competitor homophones. These findings also illustrate that syntactic factors, such as part of speech, can influence the spellings of individual words.     

Shared language: overlap and segregation of the neuronal infrastructure for speaking and listening revealed by functional MRI

Whether the brain's speech-production system is also involved in speech comprehension is a topic of much debate. Research has focused on whether motor areas are involved in listening, but overlap between speaking and listening might occur not only at primary sensory and motor levels, but also at linguistic levels (where semantic, lexical, and syntactic processes occur). Using functional MRI adaptation during speech comprehension and production, we found that the brain areas involved in semantic, lexical, and syntactic processing are mostly the same for speaking and for listening. Effects of primary processing load (indicative of sensory and motor processes) overlapped in auditory cortex and left inferior frontal cortex, but not in motor cortex, where processing load affected activity only in speaking. These results indicate that the linguistic parts of the language system are used for both speaking and listening, but that the motor system does not seem to provide a crucial contribution to listening.     

The timing of shifts of head postures during conservation

The timing of shifts of head postures in relation to speech during conservation was investigated by continuously monitoring, with a polarised light goniometer, the head movement of four subjects engaged in conservation.Postural shifts (PSs), defined as wide, linear movements, were found to occur primarily towards the initiation of speech, be it between speaking turns, or between syntactic boundaries inside speaking turns. This suggested that PSs are involved in regulating turn taking and marking syntactic boundaries inside speaking turns.Also, PSs usually started prior to and continued till after speech onset. This suggested a possible involvement in speech production, probably in helping to regulate the complex motor processes of beginning to speak.It is suggested that interactive, linguistic and speech productive functions may combine together to create a movement pattern by mutually constraining head movement.     

Apractic agraphia in a patient with normal praxis

Most right-handed crossed aphasics are not apractic. They usually have agraphia characterized by misspellings but retain the ability to write well-formed graphemes. We describe a right-handed patient with a right parietal lesion who was aphasic and not apractic. He was unable to write any formed graphemes despite a relatively preserved ability to spell aloud. We postulate that praxis and writing are dissociated in this patient because the motor engrams for praxis were located in his left hemisphere and the engrams for writing were in his right hemisphere. In addition, he comprehended commands for limb motor activities (praxis) far better than he comprehended other speech. This suggests that in this patient the areas used to comprehend limb motor commands may be anatomically distinct from areas important in comprehending other aspects of speech.     

The Study of Language in the Amyotrophic Lateral Sclerosis - Frontotemporal Spectrum Disorder: a Systematic Review of Findings and New Perspectives

Amyotrophic Lateral Sclerosis is a neurodegenerative disorder characterized primarily by motor network disruption. Extra-motor manifestations including executive functions, social cognition, and behavioral changes are now well recognized as important features of ALS, and are associated with frontotemporal and frontostriatal network disruption. However, the presence and characterization of language changes has received less attention. This systematic review characterizes the profile of reported language dysfunction in ALS. PRISMA guidelines were implemented to carry out and report the review. Current evidence suggests that areas of neuroanatomical disruption in ALS spread to language centers such as posterior, inferior frontal and superior temporal areas leading to deficits in word retrieval, syntactic and grammatical processing, and spelling. However, the majority of studies of language in ALS have been limited by the recruitment of small clinic-based prevalent samples and important questions remain regarding the incidence and progression of language impairment in ALS. Further studies from population-based incident cohorts will help to determine the range of language deficits in ALS, and how these relate to previously defined executive and behavioral sub-phenotypes.     

Transcortical sensory aphasia: Evidence for subtypes

Impaired auditory comprehension and fluent but semantically empty speech in conjunction with preserved repetition characterize the syndrome of transcortical sensory aphasia (TSA). Repetition, however, may be mediated by at least two distinct processes--a lexical process that may involve the recognition and subsequent activation of discrete stored word representations and a nonlexical process that involves phonologic decoding and immediate phonologic encoding from immediate memory. We investigated the spontaneous speech, reading, and tendency to recognize and spontaneously correct syntactic errors in four patients with TSA: this analysis suggests there are two subtypes of TSA. We contend that in one subtype both the lexical and direct repetition (or speech production) mechanisms are preserved, but in the second subtype the lexical mechanism is disrupted and repetition is mediated by the nonlexical mechanism.     

Affective aprosodia from a medial frontal stroke

BACKGROUND AND OBJECTIVES: Whereas injury to the left hemisphere induces aphasia, injury to the right hemisphere's perisylvian region induces an impairment of emotional speech prosody (affective aprosodia). Left-sided medial frontal lesions are associated with reduced verbal fluency with relatively intact comprehension and repetition (transcortical motor aphasia), but persistent affective prosodic defects associated with right medial frontal lesions have not been described. METHODS: We assessed the prosody of a man who sustained a right medial frontal cerebral infarction seven years prior. RESULTS: While propositional speech expression was normal including syntactic prosody, the patient was impaired at expressing emotions using prosody. His comprehension and repetition of prosody were also impaired but less so than expression. CONCLUSIONS: Right medial frontal lesions can induce an affective aprosodia that primarily impairs expression.     

Constraints upon word substitution speech errors

We explore the features of a corpus of naturally occurring word substitution speech errors. Words are replaced by more imageable competitors in semantic substitution errors but not in phonological substitution errors. Frequency effects in these errors are complex and the details prove difficult for any model of speech production. We argue that word frequency mainly affects phonological errors. Both semantic and phonological substitutions are constrained by phonological and syntactic similarity between the target and intrusion. We distinguish between associative and shared-feature semantic substitutions. Associative errors originate from outside the lexicon, while shared-feature errors arise within the lexicon and occur when particular properties of the targets make them less accessible than the intrusion. Semantic errors arise early while accessing lemmas from a semantic-conceptual input, while phonological errors arise late when accessing phonological forms from lemmas. Semantic errors are primarily sensitive to the properties of the semantic field involved, whereas phonological errors are sensitive to phonological properties of the targets and intrusions.