Vocal acoustic biomarkers of depression severity and treatment response

BACKGROUND

Valid, reliable biomarkers of depression severity and treatment response would provide new targets for clinical research. Noticeable differences in speech production between depressed and nondepressed patients have been suggested as a potential biomarker.

METHODS

One hundred five adults with major depression were recruited into a 4-week, randomized, double-blind, placebo-controlled research methodology study. An exploratory objective of the study was to evaluate the generalizability and repeatability of prior study results indicating vocal acoustic properties in speech may serve as biomarkers for depression severity and response to treatment. Speech samples, collected at baseline and study end point using an automated telephone system, were analyzed as a function of clinician-rated and patient-reported measures of depression severity and treatment response.

RESULTS

Regression models of speech pattern changes associated with clinical outcomes in a prior study were found to be reliable and significant predictors of outcome in the current study, despite differences in the methodological design and implementation of the two studies. Results of the current study replicate and support findings from the prior study. Clinical changes in depressive symptoms among patients responding to the treatments provided also reflected significant differences in speech production patterns. Depressed patients who did not improve clinically showed smaller vocal acoustic changes and/or changes that were directionally opposite to treatment responders.

CONCLUSIONS

This study supports the feasibility and validity of obtaining clinically important, biologically based vocal acoustic measures of depression severity and treatment response using an automated telephone system.

Effects of face masks on acoustic analysis and speech perception: Implications for peri-pandemic protocols

Wearing face masks (alongside physical distancing) provides some protection against infection from COVID-19. Face masks can also change how people communicate and subsequently affect speech signal quality. This study investigated how three common face mask types (N95, surgical, and cloth) affected acoustic analysis of speech and perceived intelligibility in healthy subjects. Acoustic measures of timing, frequency, perturbation, and power spectral density were measured. Speech intelligibility and word and sentence accuracy were also examined using the Assessment of Intelligibility of Dysarthric Speech. Mask type impacted the power distribution in frequencies above 3 kHz for the N95 mask, and above 5 kHz in surgical and cloth masks. Measures of timing and spectral tilt mainly differed with N95 mask use. Cepstral and harmonics to noise ratios remained unchanged across mask type. No differences were observed across conditions for word or sentence intelligibility measures; however, accuracy of word and sentence translations were affected by all masks. Data presented in this study show that face masks change the speech signal, but some specific acoustic features remain largely unaffected (e.g., measures of voice quality) irrespective of mask type. Outcomes have bearing on how future speech studies are run when personal protective equipment is worn.

An open-label trial in Friedreich ataxia suggests clinical benefit with high-dose resveratrol, without effect on frataxin levels

Friedreich ataxia (FRDA) is due to a triplet repeat expansion in FXN, resulting in deficiency of the mitochondrial protein frataxin. Resveratrol is a naturally occurring polyphenol, identified to increase frataxin expression in cellular and mouse models of FRDA and has anti-oxidant properties. This open-label, non-randomized trial evaluated the effect of two different doses of resveratrol on peripheral blood mononuclear cell (PBMC) frataxin levels over a 12-week period in individuals with FRDA. Secondary outcome measures included PMBC FXN mRNA, oxidative stress markers, and clinical measures of disease severity. Safety and tolerability were studied. Twenty-four participants completed the study; 12 received low-dose resveratrol (1 g daily) and 12 high-dose resveratrol (5 g daily). PBMC frataxin levels did not change in either dosage group [low-dose group change: 0.08 pg/μg protein (95% CI -0.05, 0.21, p = 0.21); high-dose group change: 0.03 pg/μg protein (95% CI -0.10, 0.15, p = 0.62)]. Improvement in neurologic function was evident in the high-dose group [change in Friedreich Ataxia Rating Scale -3.4 points, 95% CI (-6.6, -0.3), p = 0.036], but not the low-dose group. Significant improvements in audiologic and speech measures, and in the oxidative stress marker plasma F2-isoprostane were demonstrated in the high-dose group only. There were no improvements in cardiac measures or patient-reported outcome measures. No serious adverse events were recorded. Gastrointestinal side-effects were a common, dose-related adverse event. This open-label study shows no effect of resveratrol on frataxin levels in FRDA, but suggests that independent positive clinical and biologic effects of high-dose resveratrol may exist. Further assessment of efficacy is warranted in a randomized placebo-controlled trial.

Simian immunodeficiency virus infection of macaques: end-stage disease is characterized by widespread distribution of proviral DNA in tissues

Four simian immunodeficiency virus (SIV)-infected macaques in the terminal stages of AIDS were studied. Easily detectable unintegrated proviral DNA was present in nearly every tissue (lymphoid and nonlymphoid) examined. SIV-specific immunohistochemistry revealed that macrophages or macrophage-like cells were the predominant reservoirs for SIV. High burdens of infectious SIV were also characteristic of end-stage disease. At the molecular level, sequence analyses of molecular clones derived directly from tissue demonstrated that SIV, like other RNA viruses, exists as a mixture of closely related genomes. Viruses derived by cocultivation seemed to be selected for their ability to grow in tissue culture and did not represent the wide spectrum of genotypes in tissues. These data indicate that SIV-induced immunodeficiency is a complex, multisystem disease and that SIV replication, in addition to impairing the immune system, may have direct deleterious effects on multiple organ systems.

Speech-Language Pathology Guidance for Tracheostomy During the COVID-19 Pandemic: An International Multidisciplinary Perspective

Purpose As the COVID-19 pandemic has unfolded, there has been growing recognition of risks to frontline health care workers. When caring for patients with tracheostomy, speech-language pathologists have significant exposure to mucosal surfaces, secretions, and aerosols that may harbor the SARS-CoV-2 virus. This tutorial provides guidance on practices for safely performing patient evaluation and procedures, thereby reducing risk of infection. Method Data were collated through review of literature, guidelines, and consensus statements relating to COVID-19 and similar high-consequent infections, with a focus on mitigating risk of transmission to health care workers. Particular emphasis was placed on speech-language pathologists, nurses, and other allied health professionals. A multinational interdisciplinary team then analyzed findings, arriving at recommendations through consensus via electronic communications and video conference. Results Reports of transmission of infection to health care workers in the current COVID-19 pandemic and previous outbreaks substantiate the need for safe practices. Many procedures routinely performed by speech-language pathologists have a significant risk of infection due to aerosol generation. COVID-19 testing can inform level of protective equipment, and meticulous hygiene can stem spread of nosocomial infection. Modifications to standard clinical practice in tracheostomy are often required. Personal protective equipment, including either powered air-purifying respirator or N95 mask, gloves, goggles, and gown, are needed when performing aerosol-generating procedures in patients with known or suspected COVID-19 infection. Conclusions Speech-language pathologists are often called on to assist in the care of patients with tracheostomy and known or suspected COVID-19 infection. Appropriate care of these patients is predicated on maintaining the health and safety of the health care team. Careful adherence to best practices can significantly reduce risk of infectious transmission.

Decision making biases in the allied health professions: A systematic scoping review

OBJECTIVES

Cognitive and other biases can influence the quality of healthcare decision making. While substantial research has explored how biases can lead to diagnostic or other errors in medicine, fewer studies have examined how they impact the decision making of other healthcare professionals. This scoping review aimed to identify and synthesise a broad range of research investigating whether decisions made by allied health professionals are influenced by cognitive, affective or other biases.

MATERIALS AND METHODS

A systematic literature search was conducted in five electronic databases. Title, abstract and full text screening was undertaken in duplicate, using prespecified eligibility criteria designed to identify studies attempting to demonstrate the presence of bias when allied healthcare professionals make decisions. A narrative synthesis was undertaken, focussing on the type of allied health profession, type of decision, and type of bias reported within the included studies.

RESULTS

The search strategy identified 149 studies. Of these, 119 studies came from the field of psychology, with substantially fewer from social work, physical and occupational therapy, speech pathology, audiology and genetic counselling. Diagnostic and assessment decisions were the most common decision types, with fewer studies assessing treatment, prognostic or other clinical decisions. Studies investigated the presence of over 30 cognitive, affective and other decision making biases, including stereotyping biases, anchoring, and confirmation bias. Overall, 77% of the studies reported at least one outcome that represented the presence of a bias.

CONCLUSION

This scoping review provides an overview of studies investigating whether decisions made by allied health professionals are influenced by cognitive, affective or other biases. Biases have the potential to seriously impact the quality, consistency and accuracy of decision making in allied health practice. The findings highlight a need for further research particularly in professional disciplines outside of psychology, using methods that reflect real life healthcare decision making.

Evaluation of communication assessment practices during the acute stages post stroke

RATIONALE, AIMS AND OBJECTIVES

Early detection of communication impairment post stroke is an important prognostic indicator and promotes the use of individualized treatment protocols. Therefore, the methods for speech and language assessment used by communication experts in acute settings following stroke were investigated.

METHODS

A survey was conducted among 254 speech and language pathologists providing acute care for patients following stroke in all states and territories across Australia and New Zealand. Respondent attitudes and practices in speech and language assessment post stroke were recorded with a standardized questionnaire collected online.

RESULTS

A total of 174 (68.5%) speech and language pathologists responded. Over 70% of participants assessed language and 80% assessed speech using their own clinical assessments. Respondents identified limited test repeatability and poor sensitivity to change over acute periods as key areas of concern for currently available standardized assessments.

CONCLUSIONS

Subjective and/or un-standardized assessments were the most commonly used measures of communication during the acute phases post stroke. These results highlight a critical need for the development of population-specific communication assessments that build on existing clinician derived techniques and expertise while considering the acute time demands and transient nature of patient's communicative functioning.

Acoustic analysis of the effects of sustained wakefulness on speech

Exposing healthy adults to extended periods of wakefulness is known to induce changes in psychomotor functioning [Maruff et al. (2005). J. Sleep Res. 14, 21-27]. The effect of fatigue on speech is less well understood. To date, no studies have examined the pitch and timing of neurologically healthy individuals over 24 h of sustained wakefulness. Therefore, speech samples were systematically acquired (e.g., every 4 h) from 18 healthy adults over 24 h. Stimuli included automated and extemporaneous speech tasks, sustained vowel, and a read passage. Measures of timing, frequency and spectral energy were derived acoustically using PRAAT and significant changes were observed on all tasks. The effect of fatigue on speech was found to be strongest just before dawn (after 22 h). Specifically, total speech time, mean pause length, and total signal time all increased as a function of increasing levels of fatigue on the reading tasks; percentage pause and mean pause length decreased on the counting task; F4 variation decreased on the sustained vowel tasks /a:/; and alpha ratio increased on the extemporaneous speech tasks. These findings suggest that acoustic methodologies provide objective data on central nervous system functioning and that changes in speech production occur in healthy adults after just 24 h of sustained wakefulness.

The Feasibility, Utility, and Safety of Communication Interventions With Mechanically Ventilated Intensive Care Unit Patients: A Systematic Review

Purpose The aim of this study was to conduct a systematic review of the literature relating to the feasibility, utility, and safety of augmentative and alternative communication (AAC) interventions and tracheostomy-related communication interventions with mechanically ventilated adult patients in the intensive care unit (ICU). Method MEDLINE, Embase, and PsycINFO databases were searched for relevant articles. Studies were included if (a) they were performed in the ICU, (b) they involved participants > 18 years of age, (c) > 85% of participants were mechanically ventilated, and (d) they reported on content that related to the feasibility and/or utility and/or safety of AAC intervention and/or tracheostomy-related communication intervention. Studies were extracted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The levels of evidence for included studies were assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines. Results Forty-eight studies met the inclusion criteria. Different communication interventions relating to intubated and tracheostomized mechanically ventilated patients were reviewed, including (a) communication boards, (b) electrolarynx, (c) high-technology AAC devices, (d) tracheostomy tubes with communication-enabling features, (e) one-way valve in line with the ventilator, (f) ventilator-adjusted leak speech, (g) ventilator adjustments and one-way valve, and (h) multiple interventions. Forty-seven of 48 studies examined the feasibility and utility of the interventions. Sixteen studies examined the safety of the interventions. The included studies were composed of randomized controlled trials (n = 2), quasi-experimental studies (n = 7), cohort studies (n = 8), case-control (n = 1), case series (n = 23), and case reports (n = 7). The levels of evidence varied and ranged from high (n = 2), moderate (n = 7), low (n = 9), and very low (n = 30). Conclusions There is developing evidence that communication interventions with mechanically ventilated ICU patients are feasible, have utility, and are safe. Further research is warranted to guide speech pathologist-directed intervention to improve patient outcomes and the patient experience in the ICU.

Factors affecting the quality of sound recording for speech and voice analysis

The importance and utility of objective evidence-based measurement of the voice is well documented. Therefore, greater consideration needs to be given to the factors that influence the quality of voice and speech recordings. This manuscript aims to bring together the many features that affect acoustically acquired voice and speech. Specifically, the paper considers the practical requirements of individual speech acquisition configurations through examining issues relating to hardware, software and microphone selection, the impact of environmental noise, analogue to digital conversion and file format as well as the acoustic measures resulting from varying levels of signal integrity. The type of recording environment required by a user is often dictated by a variety of clinical and experimental needs, including: the acoustic measures being investigated; portability of equipment; an individual's budget; and the expertise of the user. As the quality of recorded signals is influenced by many factors, awareness of these issues is essential. This paper aims to highlight the importance of these methodological considerations to those previously uninitiated with voice and speech acoustics. With current technology, the highest quality recording would be made using a stand-alone hard disc recorder, an independent mixer to attenuate the incoming signal, and insulated wiring combined with a high quality microphone in an anechoic chamber or sound treated room.

Motor Speech Phenotypes of Frontotemporal Dementia, Primary Progressive Aphasia, and Progressive Apraxia of Speech

PURPOSE

Our purpose was to create a comprehensive review of speech impairment in frontotemporal dementia (FTD), primary progressive aphasia (PPA), and progressive apraxia of speech in order to identify the most effective measures for diagnosis and monitoring, and to elucidate associations between speech and neuroimaging.

METHOD

Speech and neuroimaging data described in studies of FTD and PPA were systematically reviewed. A meta-analysis was conducted for speech measures that were used consistently in multiple studies.

RESULTS

The methods and nomenclature used to describe speech in these disorders varied between studies. Our meta-analysis identified 3 speech measures which differentiate variants or healthy control-group participants (e.g., nonfluent and logopenic variants of PPA from all other groups, behavioral-variant FTD from a control group). Deficits within the frontal-lobe speech networks are linked to motor speech profiles of the nonfluent variant of PPA and progressive apraxia of speech. Motor speech impairment is rarely reported in semantic and logopenic variants of PPA. Limited data are available on motor speech impairment in the behavioral variant of FTD.

CONCLUSIONS

Our review identified several measures of speech which may assist with diagnosis and classification, and consolidated the brain-behavior associations relating to speech in FTD, PPA, and progressive apraxia of speech.

Role of cerebellum in fine speech control in childhood: persistent dysarthria after surgical treatment for posterior fossa tumour

Dysarthria following surgical resection of childhood posterior fossa tumour (PFT) is most commonly documented in a select group of participants with mutism in the acute recovery phase, thus limiting knowledge of post-operative prognosis for this population of children as a whole. Here we report on the speech characteristics of 13 cases seen long-term after surgical treatment for childhood PFT, unselected for the presence of post-operative mutism (mean time post-surgery=6y10m, range 1;4-12;6 years, two had post-operative mutism), and examine factors affecting outcome. Twenty-six age- and sex- matched healthy controls were recruited for comparison. Participants in both groups had speech assessments using detailed perceptual and acoustic methods. Over two-thirds of the group (69%) with removal of PFT had a profile of typically mild dysarthria. Prominent speech deficits included consonant imprecision, reduced rate, monopitch and monoloudness. We conclude that speech deficits may persist even up to 10 years post-surgery in participants who have not shown mutism in the acute phase. Of cases with unilateral lesions, poorer outcomes were associated with right cerebellar tumours compared to left, consistent with the notion based on adult data that speech is controlled by reciprocal right cerebellar/left frontal interactions. These results confirm the important role of the cerebellum in the control of fine speech movements in children.

Adults with a history of illicit amphetamine use exhibit abnormal substantia nigra morphology and parkinsonism

INTRODUCTION

The sonographic appearance of the substantia nigra is abnormally bright and enlarged (hyperechogenic) in young adults with a history of illicit stimulant use. The abnormality is a risk factor for Parkinson's disease. The aim of the current study was to identify the type of illicit stimulant drug associated with substantia nigra hyperechogenicity and to determine if individuals with a history of illicit stimulant use exhibit clinical signs of parkinsonism. We hypothesised that use of amphetamines (primarily methamphetamine) is associated with substantia nigra hyperechogenicity and clinical signs of parkinsonism.

METHODS

The area of echogenic signal in the substantia nigra was measured in abstinent human amphetamine users (n = 27; 33 ± 8 years) and in three control groups comprising a) 'ecstasy' users (n = 19; 23 ± 3 years), b) cannabis users (n = 30; 26 ± 8 years), and c) non-drug users (n = 37; 25 ± 7 years). A subset of subjects (n = 55) also underwent a neurological examination comprising the third and fifth part of the Unified Parkinson's Disease Rating Scale.

RESULTS

Area of substantia nigra echogenicity was significantly larger in the amphetamine group (0.276 ± 0.080 cm(2)) than in the control groups (0.200 ± 0.075, 0.190 ± 0.049, 0.191 ± 0.055 cm(2), respectively; P < 0.002). The score on the clinical rating scale was also significantly higher in the amphetamine group (8.4 ± 8.1) than in pooled controls (3.3 ± 2.8; P = 0.002).

CONCLUSION

Illicit use of amphetamines is associated with abnormal substantia nigra morphology and subtle clinical signs of parkinsonism. The results support epidemiological findings linking use of amphetamines, particularly methamphetamine, with increased risk of developing Parkinson's disease later in life.

Motor speech signature of behavioral variant frontotemporal dementia

Objective:

To provide a comprehensive description of motor speech function in behavioral variant frontotemporal dementia (bvFTD).

Methods:

Forty-eight individuals (24 bvFTD and 24 age- and sex-matched healthy controls) provided speech samples. These varied in complexity and thus cognitive demand. Their language was assessed using the Progressive Aphasia Language Scale and verbal fluency tasks. Speech was analyzed perceptually to describe the nature of deficits and acoustically to quantify differences between patients with bvFTD and healthy controls. Cortical thickness and subcortical volume derived from MRI scans were correlated with speech outcomes in patients with bvFTD.

Results:

Speech of affected individuals was significantly different from that of healthy controls. The speech signature of patients with bvFTD is characterized by a reduced rate (75%) and accuracy (65%) on alternating syllable production tasks, and prosodic deficits including reduced speech rate (45%), prolonged intervals (54%), and use of short phrases (41%). Groups differed on acoustic measures derived from the reading, unprepared monologue, and diadochokinetic tasks but not the days of the week or sustained vowel tasks. Variability of silence length was associated with cortical thickness of the inferior frontal gyrus and insula and speech rate with the precentral gyrus.

Conclusions:

One in 8 patients presented with moderate speech timing deficits with a further two-thirds rated as mild or subclinical. Subtle but measurable deficits in prosody are common in bvFTD and should be considered during disease management. Language function correlated with speech timing measures derived from the unprepared monologue only.

ParkinSong: A Controlled Trial of Singing-Based Therapy for Parkinson’s Disease

Background. Communication impairment is one of the most common symptoms of Parkinson’s disease (PD), significantly affecting quality of life. Singing shares many of the neural networks and structural mechanisms used during speech and, thus, has potential for therapeutic application to address speech disorders. Objective. To explore the effects of an interdisciplinary singing-based therapeutic intervention (ParkinSong) on voice and communication in people with PD. Methods. A controlled trial compared the effects of the ParkinSong intervention with an active control condition at 2 dosage levels (weekly vs monthly) over 3 months, on voice, speech, respiratory strength, and voice-related quality-of-life outcomes for 75 people living with PD. The interdisciplinary ParkinSong model comprised high-effort vocal and respiratory tasks, speech exercises, group singing, and social communication opportunities. Results. ParkinSong intervention participants demonstrated significant improvements in vocal intensity ( P = .018), maximum expiratory pressure ( P = .032), and voice-related quality of life ( P = .043) in comparison to controls. Weekly ParkinSong participants increased vocal intensity more than monthly participants ( P = .011). Vocal intensity declined in nontreatment control groups. No statistical differences between groups on maximum phonation length or maximum inspiratory pressure were observed at 3 months. Conclusions. ParkinSong is an engaging intervention with the potential to increase loudness and respiratory function in people with mild to moderately severe PD.

Differentiating profiles of speech impairments in Friedreich's ataxia: a perceptual and instrumental approach

BACKGROUND

The speech disorder associated with Friedreich's ataxia (FRDA) is classically described as ataxic dysarthria. However, variable neuropathology beyond the cerebellum, which may include the corticospinal and corticobulbar tracts, means that the dysarthria can be mixed rather than a pure ataxic dysarthria.

AIMS

To characterize physiological features of the dysarthria associated with FRDA and identify differential patterns of deviation that may occur across the subsystems of the speech-production mechanism in a series of seven case studies.

METHODS & PROCEDURES

The assessment battery included a perceptual analysis of a speech sample using an interval rating scale, and a range of instrumental measures to investigate the respiratory, laryngeal, velopharyngeal and articulatory systems.

OUTCOMES & RESULTS

The results demonstrated the variability that exists in the dysarthria associated with FRDA, highlighting the existence of differential profiles of speech impairment. A particular distinction was observed between the presence of hypernasality and phonatory dysfunction, as evidenced by the instrumental results.

CONCLUSIONS & IMPLICATIONS

The distinct profiles of dysarthria associated with FRDA indicate that approaches that address multiple subsystems are necessary for the accurate characterization and quantification of the motor speech disorder. Further research is required to investigate the decline in speech function as the disease progresses, as changes in speech function over time may be a good indicator of neurological decline in FRDA.

Comparability of modern recording devices for speech analysis: smartphone, landline, laptop, and hard disc recorder

BACKGROUND

Large-scale multi-site experimental and clinical speech protocols require high-fidelity, easy-to-use speech recording technologies. However, little is known about the reliability and comparability of affordable, portable and commonly used technologies with traditional well-validated devices (e.g., a hard disc recorder with a high-quality microphone).

OBJECTIVE

To examine the comparability of speech and voice samples acquired from protocols involving high- and low-quality devices.

METHODS

Speech samples were acquired simultaneously from 15 healthy adults using four devices and analyzed acoustically for measures of timing and voice quality. For the purpose of making initial comparisons, methods were deemed comparable if the resultant acoustic data yielded root mean squared error values ≤10% and statistically significant Spearman's correlation coefficients.

RESULTS

The data suggest that there is significant and widespread variability in the quality and reliability between different acquisition methods for voice and speech recording. Not one method provided statistically similar data to the protocol using the benchmark device (i.e., a high-quality recorder coupled with a condenser microphone). Acoustic analysis cannot be assumed to be comparable if different recording methods are used to record speech.

CONCLUSIONS

Findings have implications for researchers and clinicians hoping to make comparisons between labs or, where lower-quality devices are suggested, to offer equal fidelity.

Longitudinal change in dysarthria associated with Friedreich ataxia: a potential clinical endpoint

CNS functions that show change across short periods of time are particularly useful clinical endpoints for Friedreich ataxia. This study determined whether there is measurable acoustical change in the dysarthria associated with Friedreich ataxia across yearly intervals. A total of 29 participants diagnosed with Friedreich ataxia were recorded across 4 years at yearly intervals. A repeated measures ANOVA was used to determine which acoustic measures differed across time, and pairwise t tests were used to assess the consistency of the change across the time intervals. The relationship between the identified measures with perceptual severity was assessed with stepwise regression. Significant longitudinal change was observed with four measures that relate to the utterance duration and spectral changes in utterances. The spectral measures consistently detected change across time intervals of two or more years. The four measures combined moderately predicted perceptual severity. Together, the results implicate longitudinal change in speaking rate and utterance duration. Changes in speech associated with Friedreich ataxia can be measured across intervals of 2 years and therefore show rich potential for monitoring disease progression and therapy outcomes.

Aerosol infection of rhesus macaques with Junin virus

The purpose of our work was to determine if aerosols of Junin virus can infect rhesus macaques and if the disease is the same as that produced by virus inoculated parenterally. The 6 macaques exposed to the virus by aerosol became acutely ill during the 3rd week after exposure, and all died. Three died by day 21, while the remainder died after 1 month. Junin virus was found primarily in visceral organs of those animals dying before 21 days after infection and in the central nervous system tissues from animals dying later. Histological changes were similar to those reported in rhesus monkeys after parenteral Junin viral infection. Gastrointestinal necrosis, however, was less severe in aerosol-infected animals and the associated septicemia was not seen. High levels of alpha interferon were detected by the 3rd day in all infected macaques. Experimental Argentine hemorrhagic fever induced by aerosol infection in rhesus macaques was similar to that seen after parenteral challenge and mimicked closely the clinical syndrome observed in humans.

Quantifying ultrasonic mouse vocalizations using acoustic analysis in a supervised statistical machine learning framework

Examination of rodent vocalizations in experimental conditions can yield valuable insights into how disease manifests and progresses over time. It can also be used as an index of social interest, motivation, emotional development or motor function depending on the animal model under investigation. Most mouse communication is produced in ultrasonic frequencies beyond human hearing. These ultrasonic vocalizations (USV) are typically described and evaluated using expert defined classification of the spectrographic appearance or simplistic acoustic metrics resulting in nine call types. In this study, we aimed to replicate the standard expert-defined call types of communicative vocal behavior in mice by using acoustic analysis to characterize USVs and a principled supervised learning setup. We used four feature selection algorithms to select parsimonious subsets with maximum predictive accuracy, which are then presented into support vector machines (SVM) and random forests (RF). We assessed the resulting models using 10-fold cross-validation with 100 repetitions for statistical confidence and found that a parsimonious subset of 8 acoustic measures presented to RF led to 85% correct out-of-sample classification, replicating the experts’ labels. Acoustic measures can be used by labs to describe USVs and compare data between groups, and provide insight into vocal-behavioral patterns of mice by automating the process on matching the experts’ call types.

Automated Detection of Speech Timing Alterations in Autopsy-Confirmed Nonfluent/Agrammatic Variant Primary Progressive Aphasia

BACKGROUND AND OBJECTIVES

Motor speech function, including speech timing, is a key domain for diagnosing nonfluent/agrammatic variant primary progressive aphasia (nfvPPA). Yet, standard assessments use subjective, specialist-dependent evaluations, undermining reliability and scalability. Moreover, few studies have examined relevant anatomo-clinical alterations in patients with pathologically confirmed diagnoses. This study overcomes such caveats using automated speech timing analyses in a unique cohort of autopsy-proven cases.

METHODS

In a cross-sectional study, we administered an overt reading task and quantified articulation rate, mean syllable and pause duration, and syllable and pause duration variability. Neuroanatomical disruptions were assessed using cortical thickness and white matter (WM) atrophy analysis.

RESULTS

We evaluated 22 persons with nfvPPA (mean age: 67.3 years; 13 female patients) and confirmed underlying 4-repeat tauopathy, 15 persons with semantic variant primary progressive aphasia (svPPA; mean age: 66.5 years; 8 female patients), and 10 healthy controls (HCs; 70 years; 5 female patients). All 5 speech timing measures revealed alterations in persons with nfvPPA relative to both the HC and svPPA groups, controlling for dementia severity. The articulation rate robustly discriminated individuals with nfvPPA from HCs (area under the ROC curve [AUC] = 0.95), outperforming specialist-dependent perceptual measures of dysarthria and apraxia of speech severity. Patients with nfvPPA exhibited structural abnormalities in left precentral and middle frontal as well as bilateral superior frontal regions, including their underlying WM. The articulation rate correlated with atrophy of the left pars opercularis and supplementary/presupplementary motor areas. Secondary analyses showed that, controlling for dementia severity, all measures yielded greater deficits in patients with nfvPPA and corticobasal degeneration (nfvPPA-CBD, n = 12) than in those with progressive supranuclear palsy pathology (nfvPPA-PSP, n = 10). The articulation rate robustly discriminated between individuals in each subgroup (AUC = 0.82). More widespread cortical thinning was observed for the nfvPPA-CBD than the nfvPPA-PSP group across frontal regions.

DISCUSSION

Automated speech timing analyses can capture specific markers of nfvPPA while potentially discriminating between patients with different tauopathies. Thanks to its objectivity and scalability; this approach could support standard speech assessments.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that automated speech analysis can accurately differentiate patients with nonfluent PPA from normal controls and patients with semantic variant PPA.

Speech and oral motor profile after childhood hemispherectomy

Hemispherectomy (disconnection or removal of an entire cerebral hemisphere) is a rare surgical procedure used for the relief of drug-resistant epilepsy in children. After hemispherectomy, contralateral hemiplegia persists whereas gross expressive and receptive language functions can be remarkably spared. Motor speech deficits have rarely been examined systematically, thus limiting the accuracy of postoperative prognosis. We describe the speech profiles of hemispherectomized participants characterizing their intelligibility, articulation, phonological speech errors, dysarthric features, and execution and sequencing of orofacial speech and non-speech movements. Thirteen participants who had undergone hemispherectomy (six left, seven right; nine with congenital, four with acquired hemiplegia; operated between four months and 13 years) were investigated. Results showed that all participants were intelligible but showed a mild dysarthric profile characterized by neuromuscular asymmetry and reduced quality and coordination of movements, features that are characteristic of adult-onset unilateral upper motor neuron dysarthria, flaccid-ataxic variant. In addition, one left and four right hemispherectomy cases presented with impaired production of speech and non-speech sequences. No participant showed evidence of verbal or oral dyspraxia. It is concluded that mild dysarthria is persistent after left or right hemispherectomy, irrespective of age at onset of hemiplegia. These results indicate incomplete functional re-organization for the control of fine speech motor movements throughout childhood, and provide no evidence of hemispheric differences.