Joanne E. Folker

Dysarthria in Friedreich’s Ataxia: A Perceptual Analysis

The aims of this study were to: (1) evaluate the perceptual speech dimensions, speech intelligibility and dysarthria severity of a group of individuals diagnosed with Friedreich’s ataxia (FRDA); (2) determine the presence of subgroups within FRDA dysarthria; (3) investigate the relationship between the speech outcome and the clinical factors of disease progression. The study included 38 individuals (21 female, 17 male) with a confirmed diagnosis of FRDA. A group of 20 non-neurologically impaired individuals served as controls. Perceptual analysis, investigating 30 different dimensions of speech, was conducted on a speech sample obtained from each participant. In addition, the Assessment of Intelligibility of Dysarthria Speech was administered. All FRDA participants presented with dysarthria with severities ranging from mild to moderate. Cluster analysis revealed 3 subgroups, the first presenting with mild dysarthric symptoms, the second with increased velopharyngeal involvement and the third characterized by increased laryngeal dysfunction. Dysarthria severity showed a significant correlation to disease duration but to no other clinical measure. The findings support the notion of subgroups in FRDA dysarthria, representing distinct impairments of the speech mechanism and perhaps reflective of differing evolutions beyond the cerebellum.

Automatic method of pause measurement for normal and dysarthric speech

This study proposes an automatic method for the detection of pauses and identification of pause types in conversational speech for the purpose of measuring the effects of Friedreichs Ataxia (FRDA) on speech. Speech samples of ∼ 3 minutes were recorded from 13 speakers with FRDA and 18 healthy controls. Pauses were measured from the intensity contour and fit with bimodal lognormal distributions using the Expectation-Maximization algorithm in Matlab©. In the speakers with FRDA, both modes in the pause distributions had significantly larger means, with disproportionately fewer pauses associated with the first mode. From this preliminary study, it is concluded that distributional analysis of pause duration holds promise as a useful method of measuring the effects of FRDA on functional speech.

Differentiating Profiles of Speech Impairments in Friedreich's Ataxia: A Perceptual and Instrumental Approach.

BACKGROUND The speech disorder associated with Friedreichs 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.

Measures of spectral change and their application to habitual, slow, and clear speaking modes

Spectral measures are sensitive to dysarthric speech. However, it is unclear whether the spectral differences in dysarthric and healthy speech are due to slow articulation rate or reflect other qualitative changes in speech. Spectral measures were used to detect differences between habitual, slow, and “clear” speaking modes in 12 healthy speakers. Matched t-tests were used to determine differences in the rate and degree of spectral change between the speaking modes. Pearsons correlation coefficients were calculated to assess how well rate of spectral change predicts articulation rate (syllables per second). Clear speech had a significantly higher degree of spectral change than habitual speech, and slow speech had a significantly slower rate of spectral change than habitual and clear speaking modes. These differences occurred in all 12 speakers. The rate of spectral change was correlated with articulation rate across all speakers (range of r = .8–.9 within individual speaking modes) and therefore is a gross predictor of articulation rate. These results suggest that measures of the degree and rate of spectral change together can be used to detect changes between clear, slow, and habitual speaking modes, and hold potential as performance measures.

Nasality in Friedreich ataxia

Abstract Perceptual speech research in Friedreich ataxia (FRDA) has identified altered nasality as a key component of the dysarthria profile, however the incidence and severity of abnormal nasality remains unknown. Utilizing objective and perceptual methods, data on the relationship between resonance, disease duration, severity, age of onset and genetic profiles were collated. Thirty-seven participants with FRDA and 24 healthy controls provided contemporaneous speech samples for perceptual analysis, and single word samples for acoustic analysis. A subset of participants (eight participants with FRDA and eight controls) underwent nasometry assessment. Twenty-seven participants with FRDA presented with hypernasality and five with hyponasality on perceptual assessment. Acoustic analysis revealed participants with FRDA had greater nasality than controls (p < 0.05). Perceptual ratings of hypernasality correlated with GAA2 repeat length (ρ = 0.37, p = 0.03). Findings highlight the variability of nasality in FRDA, potentially reflecting variation in the neuropathological profile. Data also suggest the influence of genetic profiles on nasality.

Kinematic analysis of lingual movements during consonant productions in dysarthric speakers with Friedreich's ataxia: A case-by-case analysis

Articulatory kinematics were investigated using electromagnetic articulography (EMA) in four dysarthric speakers with Friedreichs ataxia (FRDA). Specifically, tongue-tip and tongue-back movements were recorded by the AG-200 EMA system during production of the consonants /t/ and /k/ as produced within a sentence utterance and during a rapid syllable repetition task. The results obtained for each of the participants with FRDA were individually compared to those obtained by a control group (n = 10). Results revealed significantly greater movement durations and increased articulatory distances, most predominantly during the approach phase of consonant production. A task difference was observed with lingual kinematics more disturbed during the syllable repetition task than during the sentence utterance. Despite expectations of slowed articulatory movements in FRDA dysarthria, the EMA data indicated that the observed prolongation of consonant phase durations was generally associated with greater articulatory distances, rather than slowed movement execution.

Voice in Friedreich Ataxia

BACKGROUND Friedreich Ataxia (FRDA) is the most common hereditary ataxia, with dysarthria as one of its key clinical signs. OBJECTIVE To describe the voice profile of individuals with FRDA to inform outcome marker development and goals of speech therapy. METHODS Thirty-six individuals with FRDA and 30 age-matched controls provided sustained vowel and connected speech samples. Speech and voice samples were analyzed acoustically using the Analysis of Dysphonia in Speech and Voice program and perceptually using the Consensus Auditory-Perceptual Evaluation of Voice form. Correlations between dysphonia and overall dysarthria severity, demographic, clinical, and genetic information were explored. RESULTS Individuals with FRDA presented with mild dysphonia characterized by hoarseness (combined roughness and breathiness), increased strain, and altered pitch variability (increased in vowel productions; slightly decreased on reading samples). Acoustically, individuals with FRDA had significantly higher scores on the Cepstral Spectral Index of Dysphonia during vowel production. A combination of perceptual and acoustic measures of dysphonia used in this study was quite effective in categorizing the FRDA versus control participants, with >80% overall accuracy. CONCLUSIONS Although dysphonia severity in FRDA did not correlate significantly with overall disease severity, speaking rate and syllabic duration significantly correlated with age at disease onset and disease duration, and also have an effect on listener perception of dysphonia. The relationship between dysphonia and dysarthria in FRDA suggests that reducing overall dysphonia severity via therapeutic techniques that improve phonatory stability and increase speaking rate is a viable target for speech therapy.

Spectral measures of the effects of Friedreich's ataxia on speech

This study identifies two measures of the effects of Friedreichs ataxia (FRDA) on speech motor control. Speech samples of 17 healthy controls and 37 speakers with dysarthria associated with FRDA were recorded during one structured and one unstructured speaking task. Two measures of spectral variation were used that relate to the rate and range of changes that occur in the spectral envelope. Linear mixed models revealed significant effects of GROUP, TASK, and GROUP*TASK. FRDA speech samples had slower rate of spectral change and reduced spectral range. Healthy speakers produced faster rates of spectral change in read text compared to conversation, but speakers with dysarthria did not. The results suggest that structured speaking tasks which demand large spectral variation may be particularly useful in assessing the dysarthria. It is concluded that the rate of spectral change is a useful measure of dysarthria associated with FRDA.

Treatment for dysphagia (swallowing difficulties) in hereditary ataxia syndromes

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the efficacy of interventions for swallowing impairment (dysphagia) in people with hereditary ataxia syndromes.

Dysarthria in Friedreich’s ataxia

Objective: To assess the neuropsychological outcome as a safety measure and quality control in patients with subthalamic nucleus (STN) stimulation for PD. Background: Deep brain stimulation (DBS) is considered a relatively safe treatment used in patients with movement disorders. However, neuropsychological alterations have been reported in patients with STN DBS for PD. Cognition and mood are important determinants of quality of life in PD patients and must be assessed for safety control. Methods: Seventeen consecutive patients (8 women) who underwent STN DBS for PD have been assessed before and 4 months after surgery. Besides motor symptoms (UPDRS-III), mood (Beck Depression Inventory, Hamilton Depression Rating Scale) and neuropsychological aspects, mainly executive functions, have been assessed (mini mental state examination, semantic and phonematic verbal fluency, go-no go test, stroop test, trail making test, tests of alertness and attention, digit span, wordlist learning, praxia, Boston naming test, figure drawing, visual perception). Paired t-tests were used for comparisons before and after surgery. Results: Patients were 61.6±7.8 years old at baseline assessment. All surgeries were performed without major adverse events. Motor symptoms ‘‘on’’ medication remained stable whereas they improved in the ‘‘off’’ condition (p<0.001). Mood was not depressed before surgery and remained unchanged at follow-up. All neuropsychological assessment outcome measures remained stable at follow-up with the exception of semantic verbal fluency and wordlist learning. Semantic verbal fluency decreased by 21±16% (p<0.001) and there was a trend to worse phonematic verbal fluency after surgery (p=0.06). Recall of a list of 10 words was worse after surgery only for the third attempt of recall (13%, p<0.005). Conclusions: Verbal fluency decreased in our patients after STN DBS, as previously reported. The procedure was otherwise safe and did not lead to deterioration of mood.Objective: Study the subthalamic (STN) neuronal activity in patients with Obsessive Compulsive Disorders (OCD). Background: Dysfunction in the basal ganglia circuitry has been implicated in obsessive and compulsive disorder (OCD). In a recent clinical research program, high frequency electrical stimulation of the STN has proved to be efficient in alleviating obsessions and compul sions in OCD patients and permitted to study neuronal activity in this disorder (Mallet et al, 2008). Methods: Unit neuronal activity of STN neurons were recorded in awake OCD patients at rest and compared to data obtained in patients with Parkinson’s disease (PD). The mean firing rate and interspike intervals were calculated for each cell. The firing pattern was classified as regular, irregular or bursting (Kaneoke and Vitek, 1996). Neuronal activity was also sampled for each period and epochs of elevated discharge rate were classified as burst using a Poisson surprise analysis. Spike trains with S>=3 were considered to be bursts. Percentages of action potentials and duration with S>=3 and mean S value were calculated for each cell. The precise localization of neuronal activity recordings was performed using a 3-D deformable basal ganglia atlas with a particular reference to STN subterritories. Results: 156 STN neurons were isolated in 11 OCD patients and 113 neurons in 10 PD patients. In comparison to PD, the mean discharge frequency of STN neurons was lower in OCD patient (24.1+/-14.1 Hz vs 32.1+/-17.7 Hz, P =3 (17.7 6 4.7 vs 14.9 6 5.6 %, P<10-4). Conclusions: In OCD patients, the subthalamic neuronal activity seems abnormal with an increase in the bursting type activity. This is in line with the hypothesis of the role of basal ganglia, and the subthalamic nucleus, in the physiopathology of this disorder.Objective: To test the hypothesis that balance control in Parkinson’s disease (PD) is asymmetrically affected using system identification techniques. Background: PD is an asymmetrical disease. It is unknown whether axial symptoms, such as impaired balance, also show asymmetry. Clinical scales used to assess disease severity do not explicitly evaluate asymmetries in axial symptoms. Evaluation of asymmetrical balance control might improve our understanding and treatment of axial symptoms. Methods: Eight patients with idiopathic PD were asked to maintain their balance during continuous random translational platform movements. Body sway angle and reactive forces of each foot were recorded. These yielded the Frequency Response Function (FRF) of the stabilizing mechanisms, which expresses the amount and timing of the generated corrective torque in response to sway at the specified frequencies. The FRFs were used to calculate the relative contribution of each ankle to the total amount of generated corrective torque to resist the perturbations. In addition, the amount of weight bearing of each leg was calculated. Furthermore, the motor part of the UPDRS and the Hoehn & Yahr disease stage were also evaluated. Results: Results showed that six out of eight patients responded asymmetrically to the induced platform perturbations as shown by corrective ankle torques. Hence, one leg contributed significantly more to balance control than the other and there was no clear relationship between the contribution to weight bearing and to balance control. Conclusions: Balance control in PD patients proved asymmetrical for some patients. This asymmetry of axial symptoms can be reliably identified with system identification techniques in the frequency domain. In this way, the effects of different treatments can be identified for each leg separately.