Impairments of speech fluency in Lewy body spectrum disorder

Few studies have examined connected speech in demented and non-demented patients with Parkinson’s disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions.     

Impairment of temporal organization of speech in basal ganglia diseases.

Absolute and relative speech timing were examined in patients suffering from Parkinson's, Huntington's, and Wilson's disease. The task was to speak a standard sentence 10 times, first slowly, and then successively faster up to maximum rate. All patient groups had low maximal speech rates and showed decreased variability of speech rate. The duration of pauses between words was the same as in normals and the relative time structure of the test sentence was basically preserved. For comparison, two cases with nonfluent aphasia had even slower speech rates, large increases in pause duration, and major changes in relative speech timing. The results show the same type of alterations of the temporal organization of speech as those characteristic for rapid alternating limb movements in such patients. They support the view that the speech and skeletomotor systems share common neural control modes despite fundamental biomechanical differences. The common denominator between the speech and the skeletomotor disturbances in basal ganglia diseases may be the undamping and slowing of a fast central oscillator.     

Impaired perception of vocal emotions in Parkinson's disease: influence of speech time processing and executive functioning

Little is known about the underlying dimensions of impaired recognition of emotional prosody that is frequently observed in patients with Parkinson's disease (PD). Because patients with PD also suffer from working memory deficits and impaired time perception, the present study examined the contribution of (a) working memory (frontal executive functioning) and (b) processing of the acoustic parameter speech rate to the perception of emotional prosody in PD. Two acoustic parameters known to be important for emotional classifications (speech duration and pitch variability) were systematically varied in prosodic utterances. Twenty patients with PD and 16 healthy controls (matched for age, sex, and IQ) participated in the study. The findings imply that (1) working memory dysfunctions and perception of emotional prosody are not independent in PD, (2) PD and healthy control subjects perceived vocal emotions categorically along two acoustic manipulation continua, and (3) patients with PD show impairments in processing of speech rate information.     

Understanding speaker attitudes from prosody by adults with Parkinson's disease

The ability to interpret vocal (prosodic) cues during social interactions can be disrupted by Parkinson's disease, with notable effects on how emotions are understood from speech. This study investigated whether PD patients who have emotional prosody deficits exhibit further difficulties decoding the attitude of a speaker from prosody. Vocally inflected but semantically nonsensical ‘pseudo‐utterances’ were presented to listener groups with and without PD in two separate rating tasks. Task 1 required participants to rate how confident a speaker sounded from their voice and Task 2 required listeners to rate how polite the speaker sounded for a comparable set of pseudo‐utterances. The results showed that PD patients were significantly less able than HC participants to use prosodic cues to differentiate intended levels of speaker confidence in speech, although the patients could accurately detect the polite/impolite attitude of the speaker from prosody in most cases. Our data suggest that many PD patients fail to use vocal cues to effectively infer a speaker's emotions as well as certain attitudes in speech such as confidence, consistent with the idea that the basal ganglia play a role in the meaningful processing of prosodic sequences in spoken language ( Pell & Leonard, 2003 ).     

Treating Parkinsonian speech: development of a feedback rating scale using a case study

The speech of people with Parkinson's disease is often unintelligible because the speaker has limited volume and imprecisely articulated speech. The Lee Silverman Voice Treatment addresses volume by requiring a patient to exert extreme effort to adduct the vocal folds and increase volume. Little attention, however, is paid to articulation. Such patients often have perceptual difficulties which prevent them from monitoring their own volume and speech. A case study presents a method for improving volume and articulation of speech of a patient with Parkinson's disease by focusing on perceptual aspects of speech.     

Phonological and articulatory impairment in Alzheimer's disease: a case series

We demonstrate that phonological and articulatory impairments may occur at presentation or early in the course of Alzheimer's disease, contrary to claims that these aspects of language production are relatively preserved until the final stages of this disease. Six patients with pathologically confirmed Alzheimer's disease (AD) and four patients with clinically diagnosed dementia of the Alzheimer's type (DAT) presented with one of five different clinical profiles: nonfluent progressive aphasia, mixed progressive aphasia, progressive aphasia diagnosed as DAT from neuropsychological assessment, initial amnestic syndrome with prominent phonological errors, and biparietal syndrome. Analysis of their conversational speech, single-word production, and performance of highly familiar series speech tasks such as counting revealed false start errors, phonological paraphasias, and/or articulatory difficulty. Neuropathological changes were located in left perisylvian regions consistent with speech and language impairment but atypical for Alzheimer's disease.     

Expressive prosodic patterns in individuals with Alzheimer's disease

This paper describes a useful technique for quantifying the degree of speech deficits in dementia of GDS 4 Alzheimer's type (DAT). Production of prosodic speech in DAT patients and healthy older controls was analysed using variation in fundamental frequency (F0) measures on a reading task. The prosogram computational model was used to analyze the prosodic contours of the speech samples, using melodic styling of F0 based on perceptual principles and prominence detection of spectral and amplitude fluctuations in the speech signal. Results revealed significant differences in most of these prosodic parameters among the DAT group. Normal pitch variation in speech and variations in syllable timing were reduced in the DAT group, these features cause "flat" speech prosody in these patients. These speech parameters may have diagnostic and prognostic value for Alzheimer's disease and therefore could be a useful aid in clinical trials.     

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.     

The influence of speaking rate on articulatory hypokinesia in parkinsonian dysarthria

This study addressed the question of whether or not speaking rate influences articulatory hypokinesia in dysarthria associated with Parkinson's disease. Analyses of parkinsonian speech samples revealed mean speaking rates consistent with normal controls. Thus, speaking rate was not abnormal overall in this group of dysarthric subjects. Kinematic analyses of labial displacement amplitude, peak instantaneous velocity, and movement time were made during repetitive syllable production spoken at two speaking rates: 3-5 syllables/sec and 5-7 syllables/sec. The results suggested that labial movements were normal at the slower of the two speaking rates. Conversely, labial movements became hypokinetic as speaking rate increased to the rate consistent with conversational speech. These findings provide a physiologic basis for the perception of hypokinetic dysarthria in Parkinson's disease and suggest that speaking rate may be an important control variable contributing to articulatory hypokinesia in Parkinson's disease. Moreover, these findings provide quantitative evidence that articulatory hypokinesia plays a dominant role in the perception of parkinsonian dysarthria.     

Oral Motor Abilities Are Task Dependent: A Factor Analytic Approach to Performance Rate

Measures of performance rates in speech-like or volitional nonspeech oral motor tasks are frequently used to draw inferences about articulation rate abnormalities in patients with neurologic movement disorders. The study objective was to investigate the structural relationship between rate measures of speech and of oral motor behaviors different from speech. A total of 130 patients with neurologic movement disorders and 130 healthy subjects participated in the study. Rate data was collected for oral reading (speech), rapid syllable repetition (speech-like), and rapid single articulator movements (nonspeech). The authors used factor analysis to determine whether the different rate variables reflect the same or distinct constructs. The behavioral data were most appropriately captured by a measurement model in which the different task types loaded onto separate latent variables. The data on oral motor performance rates show that speech tasks and oral motor tasks such as rapid syllable repetition or repetitive single articulator movements measure separate traits.     

Changes in functional cerebral laterality of patients with torticollis spasmodicus

By comparing the results of tapping with and without simultaneous speaking and by evaluating their lateral differences the probable lateralization of functional speech centre was established in 28 patients with torticollis spasmodicus and 28 healthy controls. In doing this, it became evident that unlike the controls the patients as a hole in a significant way lateralized the speech centre more frequently to the right. The changed cerebral laterality in the patients was supposed to be stimulated by pronounced emotional conflicts and to be involved in the disease of torticollis spasmodicus.     

The organization of narrative discourse in Lewy body spectrum disorder

Narrative discourse is an essential component of day-to-day communication, but little is known about narrative in Lewy body spectrum disorder (LBSD), including Parkinson’s disease (PD), Parkinson’s disease with dementia (PDD), and dementia with Lewy bodies (DLB). We performed a detailed analysis of a semi-structured speech sample in 32 non-aphasic patients with LBSD, and we related their narrative impairments to gray matter (GM) atrophy using voxel-based morphometry. We found that patients with PDD and DLB have significant difficulty organizing their narrative speech. This was correlated with deficits on measures of executive functioning and speech fluency. Regression analyses associated this deficit with reduced cortical volume in inferior frontal and anterior cingulate regions. These findings are consistent with a model of narrative discourse that includes executive as well as language components and with an impairment of the organizational component of narrative discourse in patients with PDD and DLB.     

Task-related factors in oral motor control: speech and oral diadochokinesis in dysarthria and apraxia of speech

This study was focused on the potential influence of task-related factors on oral motor performance in patients with speech disorders. Sentence production was compared with a nonspeech oral motor task, i.e., oral diadochokinesis. Perceptual and acoustic measures of speech impairment were used as dependent variables. Between-task comparisons were made for subsamples of a population of 140 patients with different motor speech syndromes, including apraxia of speech and cerebellar dysarthria. In a further analysis subgroups were matched for speaking rate. Overall, dysdiadochokinesis was correlated with the degree of speech impairment, but there was a strong interaction between task type and motor speech syndrome. In particular, cerebellar pathology affected DDK to a relatively greater extent than sentence production, while apraxic pathology spared the ability of repeating syllables at maximum speed.     

Effects of cognitive impairment on prosodic parameters of speech production planning in multiple sclerosis

Cognitive impairment (CI) affects 40–65% of patients with multiple sclerosis (MS). CI can have a negative impact on a patient's everyday activities, such as engaging in conversations. Speech production planning ability is crucial for successful verbal interactions and thus for preserving social and occupational skills. This study investigates the effect of cognitive-linguistic demand and CI on speech production planning in MS, as reflected in speech prosody. A secondary aim is to explore the clinical potential of prosodic features for the prediction of an individual's cognitive status in MS. A total of 45 subjects, that is 22 healthy controls (HC) and 23 patients in early stages of relapsing-remitting MS, underwent neuropsychological tests probing specific cognitive processes involved in speech production planning. All subjects also performed a read speech task, in which they had to read isolated sentences manipulated as for phonological length. Results show that the speech of MS patients with CI is mainly affected at the temporal level (articulation and speech rate, pause duration). Regression analyses further indicate that rate measures are correlated with working memory scores. In addition, linear discriminant analysis shows the ROC AUC of identifying MS patients with CI is 0.70 (95% confidence interval: 0.68–0.73). Our findings indicate that prosodic planning is deficient in patients with MS-CI and that the scope of planning depends on patients’ cognitive abilities. We discuss how speech-based approaches could be used as an ecological method for the assessment and monitoring of CI in MS.     

Listening rate and comprehension as a function of preference for and exposure to time-altered speech

We conducted experiments on the effects of brief prior exposure to time-altered speech on preferred listening rate and the rate listeners would select when asked to listen to speech as fast as possible with good compression (induced listening rate). In Exp. 1, 48 participants were exposed either to normal rate speech or to speech compressed to twice-normal rate. Brief exposure to twice-normal rate speech led to a faster induced listening rate than exposure to normal rate speech. In Exp. 2, 31 participants were briefly exposed to normal rate speech, speech compressed to twice-normal rate, or speech expanded to half-normal rate. The faster the rate of the exposure speech, the faster the induced rate. Speech compressed to twice-normal rate led to a faster induced listening rate than exposure to speech expanded to half-normal rate. Normal rate speech was intermediate between twice-normal and half-normal rate and did not differ significantly from them. Induced listening rate was a linear combination of listening rate preference and recent forced exposure to time-altered speech.     

An Acoustic Analysis of Rate of Speech Effects on Vowel Production in Aphasia

The present investigation examined the production of tense and lax vowel duration differences at two speaking rates in the speech of 10 nonfluent aphasics, 8 fluent aphasics, and 10 normal control subjects. Subjects produced four repetitions of each of the vowels [i e æ o u I ε υ Λ] at each speaking rate. Acoustic analyses revealed that subjects in all three groups were able to manipulate overall rate of speech. In addition, normal controls and fluent aphasic subjects produced vowels under the fast rate condition which were significantly shorter than those under the slow rate condition. Despite a change in overall speaking rate, the nonfluent aphasics did not exhibit a significant difference in vowel duration at the two rates of speech, suggesting a deficit in the implementation of this temporal parameter. Both normal controls and fluent aphasic patients produced nonoverlapping distributions of tense and lax vowels at both speaking rates. In contrast, the nonfluent aphasics demonstrated a great deal of overlap in the distribution of tense and lax vowel durations at the fast rate. Results are discussed in relation to the nature of the speech production deficits in nonfluent and fluent aphasic patients.     

The contribution of apraxic speech to working memory deficits in Parkinson's disease

This article links two formerly separate areas of research associated with Parkinson's disease (PD): speech and memory. It is proposed that speech deficits occur in PD not merely at the level of muscular control, as is commonly termed dysarthria, but also at the level of speech planning and programming, more aptly described as a form of apraxia. It is further argued that PD patient groups exhibit small deficits in verbal span, and the link between apraxic speech and verbal span is elucidated via Baddeley's (1986) model of working memory. An experiment is described in which aspects of speech of 36 PD and 43 healthy control subjects were rated and classified, and measures of span and articulation rate for words of different syllable lengths were taken. Twenty-three PD subjects had dysarthric speech, while 14 of them had apraxic speech, which was associated with lower memory span scores for longer words. It is concluded that apraxic speech can be a source of reduced memory span in PD. In addition to implications for rehabilitation and therapeutic work with PD sufferers, these findings advance our theoretical understanding of the Parkinsonian syndrome.     

Speech rhythm alterations in Spanish-speaking individuals with Alzheimer’s disease

Rhythm is the speech property related to the temporal organization of sounds. Considerable evidence is now available for suggesting that dementia of Alzheimer’s type is associated with impairments in speech rhythm. The aim of this study is to assess the use of an automatic computerized system for measuring speech rhythm characteristics in an oral reading task performed by 45 patients with Alzheimer’s disease (AD) compared with those same characteristics among 82 healthy older adults without a diagnosis of dementia, and matched by age, sex and cultural background. Ranges of rhythmic-metric and clinical measurements were applied. The results show rhythmic differences between the groups, with higher variability of syllabic intervals in AD patients. Signal processing algorithms applied to oral reading recordings prove to be capable of differentiating between AD patients and older adults without dementia with an accuracy of 87% (specificity 81.7%, sensitivity 82.2%), based on the standard deviation of the duration of syllabic intervals. Experimental results show that the syllabic variability measurements extracted from the speech signal can be used to distinguish between older adults without a diagnosis of dementia and those with AD, and may be useful as a tool for the objective study and quantification of speech deficits in AD.     

The association between auditory memory span and speech rate in children from kindergarten to sixth grade.

This study reexamined the association between speech rate and memory span in children from kindergarten to sixth grade (N = 152) in order to potentially account for the inconsistencies within the published literature on this topic. Some of the inconsistencies in past research may reflect the different methods adopted in assessing speech rate. In particular, repeating word triples may itself involve memory demands, contaminating the correlation between speech rate and memory span in younger children. Analyses using composite speech rate and memory span measures showed that speech rate for word triples shared variance with memory span that was independent of speech rate for single words. Moreover, speech rate for word triples was largely redundant with age in explaining additional variation in memory span once the effects of speech rate for single words were controlled.