Facial nerve neurographies in intensive care unit-acquired weakness.

BACKGROUND: Patients with an intensive care unit-acquired weakness (ICU-AW) often present clinically with severe paresis of the limb and trunk muscles while facial muscles appear less affected. To investigate whether the facial nerves are partially spared from this condition, we performed both peripheral and cranial nerve conduction studies in critically ill patients. METHODS: In patients requiring prolonged ICU therapy, the motor and sensory nerve conduction velocities of the peroneal, ulnar and facial nerves and the muscle action potentials of the associated muscles, as well as the orbicularis oculi reflexes were assessed shortly after admission, and on ICU days 7 and 14. RESULTS: Eighteen patients were included in the final data analysis (average age 54.2 ± 16.8 years, 8 females). The amplitudes of the peroneal nerve compound muscle action potentials (CMAPs) were reduced in all patients at ICU days 7 and 14 (F(1.39; 23.63) = 13.85; p < 0.001). There was no similar decrease in the CMAP amplitudes of the ulnar or facial nerve. Other parameters of nerve function (latencies, sensory and motor nerve conduction velocities, sensory nerve action potentials) remained unchanged. The reproducibility of the orbicularis oculi reflex was reduced during the disease course, while its latencies did not change significantly during the disease course. CONCLUSIONS: There is a relative preservation of CMAPs in facial and hand as opposed to foot muscles. This is compatible with the clinical observation that the facial muscles in patients with ICU-AW are less severely affected. This may be primarily a function of the nerve length, and consequently more robust trophic factors in shorter nerves. Trial registration This study was prospectively registered in the German Clinical Trial Register on April 20th 2020 (DRKS00021467).

UV-Light-Tunable p-/n-Type Chemiresistive Gas Sensors Based on Quasi-1D TiS3 Nanoribbons: Detection of Isopropanol at ppm Concentrations.

The growing demand of society for gas sensors for energy-efficient environmental sensing stimulates studies of new electronic materials. Here, we investigated quasi-one-dimensional titanium trisulfide (TiS3) crystals for possible applications in chemiresistors and on-chip multisensor arrays. TiS3 nanoribbons were placed as a mat over a multielectrode chip to form an array of chemiresistive gas sensors. These sensors were exposed to isopropanol as a model analyte, which was mixed with air at low concentrations of 1-100 ppm that are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit. The tests were performed at room temperature (RT), as well as with heating up to 110 °C, and under an ultraviolet (UV) radiation at λ = 345 nm. We found that the RT/UV conditions result in a n-type chemiresistive response to isopropanol, which seems to be governed by its redox reactions with chemisorbed oxygen species. In contrast, the RT conditions without a UV exposure produced a p-type response that is possibly caused by the enhancement of the electron transport scattering due to the analyte adsorption. By analyzing the vector signal from the entire on-chip multisensor array, we could distinguish isopropanol from benzene, both of which produced similar responses on individual sensors. We found that the heating up to 110 °C reduces both the sensitivity and selectivity of the sensor array.

White matter connectivity in neonates at risk of stuttering: Preliminary data.

BACKGROUND: Developmental stuttering is thought to be underpinned by structural impairments in the brain. The only way to support the claim that these are causal is to determine if they are present before onset. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) was conducted on 18 neonates, aged 8-18 weeks, 6 of whom were determined to be genetically at risk of stuttering. RESULTS: With tract-based spatial statistics (TBSS) analysis, no statistically significant differences were found between the at-risk group and the control group. However, fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) in the corpus callosum of the at-risk group were lower (uncorrected) than in the control group. Automated Fiber Quantification (AFQ) yielded lower FA in the at-risk group than in the control group in the medial section of the callosum forceps minor. DISCUSSION: The findings, albeit with a small number of participants, support the proposition that reduced integrity of white matter in the corpus callosum has a causal role in developmental stuttering. Longitudinal research to determine if children with this impairment at birth later start to stutter is needed to confirm this. The left arcuate fasciculus is thought to develop as speech develops, which likely explains why there were no abnormal findings in this area in our at-risk neonates so soon after birth. This is the first study to investigate the brains of children before the onset of stuttering, and the findings warrant further research.

Stuttering severity relates to frontotemporal low-beta synchronization during pre-speech preparation.

OBJECTIVE: The neurophysiological dynamics of the occurrence of a stuttering event are largely unknown. This sensor-level EEG study investigated whether already the intention to speak alters the formation of the speech production network in stuttering. METHODS: We studied alpha (8-13 Hz), low beta (15-25 Hz) and high beta (25-30 Hz) power modulation in 19 adults with developmental stuttering (AWS) and 19 fluently speaking control participants during speech intention. RESULTS: Both groups show that the anticipation of overt reading coincides with broadband low-frequency suppression in posterior sensors, a common sign of network formation for speech production. Prior to fluent speech, frontotemporal alpha and low-beta power were weaker in AWS with mild stuttering but stronger in AWS with severe stuttering. These correlations were not significant prior stuttered speech. Further, post hoc comparisons confirmed the difference between AWS with mild and severe stuttering in low beta power. CONCLUSIONS: AWS with more severe stuttering seem to show stronger maintenance of the current cognitive or sensorimotor state, as stuttering severity was associated with increased beta power. Increased beta power levels may influence subsequent speech preparation and execution processes. SIGNIFICANCE: Upcoming breakdowns of the speech production network as evident in actual stuttering are related to beta power during the intention to speak.

White matter tract strength correlates with therapy outcome in persistent developmental stuttering.

Persistent stuttering is a prevalent neurodevelopmental speech disorder, which presents with involuntary speech blocks, sound and syllable repetitions, and sound prolongations. Affected individuals often struggle with negative feelings, elevated anxiety, and low self-esteem. Neuroimaging studies frequently link persistent stuttering with cortical alterations and dysfunctional cortico-basal ganglia-thalamocortical loops; dMRI data also point toward connectivity changes of the superior longitudinal fasciculus (SLF) and the frontal aslant tract (FAT). Both tracts are involved in speech and language functions, and the FAT also supports inhibitory control and conflict monitoring. Whether the two tracts are involved in therapy-associated improvements and how they relate to therapeutic outcomes is currently unknown. Here, we analyzed dMRI data of 22 patients who participated in a fluency-shaping program, 18 patients not participating in therapy, and 27 fluent control participants, measured 1 year apart. We used diffusion tractography to segment the SLF and FAT bilaterally and to quantify their microstructural properties before and after a fluency-shaping program. Participants learned to speak with soft articulation, pitch, and voicing during a 2-week on-site boot camp and computer-assisted biofeedback-based daily training for 1 year. Therapy had no impact on the microstructural properties of the two tracts. Yet, after therapy, stuttering severity correlated positively with left SLF fractional anisotropy, whereas relief from the social-emotional burden to stutter correlated negatively with right FAT fractional anisotropy. Thus, posttreatment, speech motor performance relates to the left dorsal stream, while the experience of the adverse impact of stuttering relates to the structure recently associated with conflict monitoring and action inhibition.

Effect of Pulse Duration and Direction on Plasticity Induced by 5 Hz Repetitive Transcranial Magnetic Stimulation in Correlation With Neuronal Depolarization.

Introduction: High frequency repetitive transcranial magnetic stimulation applied to the motor cortex causes an increase in the amplitude of motor evoked potentials (MEPs) that persists after stimulation. Here, we focus on the aftereffects generated by high frequency controllable pulse TMS (cTMS) with different directions, intensities, and pulse durations. Objectives: To investigate the influence of pulse duration, direction, and amplitude in correlation to induced depolarization on the excitatory plastic aftereffects of 5 Hz repetitive transcranial magnetic stimulation (rTMS) using bidirectional cTMS pulses. Methods: We stimulated the hand motor cortex with 5 Hz rTMS applying 1,200 bidirectional pulses with the main component durations of 80, 100, and 120 µs using a controllable pulse stimulator TMS (cTMS). Fourteen healthy subjects were investigated in nine sessions with 80% resting motor threshold (RMT) for posterior-anterior (PA) and 80 and 90% RMT anterior-posterior (AP) induced current direction. We used a model approximating neuronal membranes as a linear first order low-pass filter to estimate the strength-duration time constant and to simulate the membrane polarization produced by each waveform. Results: PA and AP 5 Hz rTMS at 80% RMT produced no significant excitation. An exploratory analysis indicated that 90% RMT AP stimulation with 100 and 120 µs pulses but not 80 µs pulses led to significant excitation. We found a positive correlation between the plastic outcome of each session and the simulated peak neural membrane depolarization for time constants >100 µs. This correlation was strongest for neural elements that are depolarized by the main phase of the AP pulse, suggesting the effects were dependent on pulse direction. Conclusions: Among the tested conditions, only 5 Hz rTMS with higher intensity and wider pulses appeared to produce excitatory aftereffects. This correlated with the greater depolarization of neural elements with time constants slower than the directly activated neural elements responsible for producing the motor output (e.g., somatic or dendritic membrane). Significance: Higher intensities and wider pulses seem to be more efficient in inducing excitation. If confirmed, this observation could lead to better results in future clinical studies performed with wider pulses.

Fluency shaping increases integration of the command-to-execution and the auditory-to-motor pathways in persistent developmental stuttering.

Fluency-shaping enhances the speech fluency of persons who stutter, yet underlying conditions and neuroplasticity-related mechanisms are largely unknown. While speech production-related brain activity in stuttering is well studied, it is unclear whether therapy repairs networks of altered sensorimotor integration, imprecise neural timing and sequencing, faulty error monitoring, or insufficient speech planning. Here, we tested the impact of one-year fluency-shaping therapy on resting-state fMRI connectivity within sets of brain regions subserving these speech functions. We analyzed resting-state data of 22 patients who participated in a fluency-shaping program, 18 patients not participating in therapy, and 28 fluent control participants, measured one year apart. Improved fluency was accompanied by an increased connectivity within the sensorimotor integration network. Specifically, two connections were strengthened; the left inferior frontal gyrus showed increased connectivity with the precentral gyrus at the representation of the left laryngeal motor cortex, and the left inferior frontal gyrus showed increased connectivity with the right superior temporal gyrus. Thus, therapy-associated neural remediation was based on a strengthened integration of the command-to-execution pathway together with an increased auditory-to-motor coupling. Since we investigated task-free brain activity, we assume that our findings are not biased to network activity involved in compensation but represent long-term focal neuroplasticity effects.

Two cortical representations of voice control are differentially involved in speech fluency.

Recent studies have identified two distinct cortical representations of voice control in humans, the ventral and the dorsal laryngeal motor cortex. Strikingly, while persistent developmental stuttering has been linked to a white-matter deficit in the ventral laryngeal motor cortex, intensive fluency-shaping intervention modulated the functional connectivity of the dorsal laryngeal motor cortical network. Currently, it is unknown whether the underlying structural network organization of these two laryngeal representations is distinct or differently shaped by stuttering intervention. Using probabilistic diffusion tractography in 22 individuals who stutter and participated in a fluency shaping intervention, in 18 individuals who stutter and did not participate in the intervention and in 28 control participants, we here compare structural networks of the dorsal laryngeal motor cortex and the ventral laryngeal motor cortex and test intervention-related white-matter changes. We show (i) that all participants have weaker ventral laryngeal motor cortex connections compared to the dorsal laryngeal motor cortex network, regardless of speech fluency, (ii) connections of the ventral laryngeal motor cortex were stronger in fluent speakers, (iii) the connectivity profile of the ventral laryngeal motor cortex predicted stuttering severity (iv) but the ventral laryngeal motor cortex network is resistant to a fluency shaping intervention. Our findings substantiate a weaker structural organization of the ventral laryngeal motor cortical network in developmental stuttering and imply that assisted recovery supports neural compensation rather than normalization. Moreover, the resulting dissociation provides evidence for functionally segregated roles of the ventral laryngeal motor cortical and dorsal laryngeal motor cortical networks.

Prevalence and Therapy Rates for Stuttering, Cluttering, and Developmental Disorders of Speech and Language: Evaluation of German Health Insurance Data.

PURPOSE: To evaluate the prevalence and treatment patterns of speech and language disorders in Germany. METHODS: A retrospective analysis of data collected from 32% of the German population, insured by the statutory German health insurance (AOK, Local Health Care Funds). We used The International Statistical Classification of Diseases and Related Health Problems, 10th revision, German Modification (ICD-10 GM) codes for stuttering (F98.5), cluttering (F98.6), and developmental disorders of speech and language (F80) to identify prevalent and newly diagnosed cases each year. Prescription and speech therapy reimbursement data were used to evaluate treatment patterns. RESULTS: In 2017, 27,977 patients of all ages were diagnosed with stuttering (21,045 males, 75% and 6,932 females, 25%). Stuttering prevalence peaks at age 5 years (boys, 0.89% and girls, 0.40%). Cluttering was diagnosed in 1,800 patients of all ages (1,287 males, 71.5% and 513 females, 28.5%). Developmental disorders of speech and language were identified in 555,774 AOK-insurants (61.2% males and 38.8% females). Treatment data indicate a substantial proportion newly diagnosed stuttering individuals receive treatment (up to 45% of 6-year-old patients), with slightly fewer than 20 sessions per year, on average. We confirmed a previous study showing increased rates of atopic disorders and neurological and psychiatric comorbidities in individuals with stuttering, cluttering, and developmental disorders of speech and language. CONCLUSION: This is the first nationwide study using health insurance data to analyze the prevalence and newly diagnosed cases of a speech and language disorder. Prevalence and gender ratio data were consistent with the international literature. The crude prevalence of developmental disorders of speech and language increased from 2015 to 2018, whereas the crude prevalence for stuttering remained stable. For cluttering, the numbers were too low to draw reliable conclusions. Proportional treatment allocation for stuttering peaked at 6 years of age, which is the school entrance year, and is later than the prevalence peak of stuttering.

Enlarged Area of Mesencephalic Iron Deposits in Adults Who Stutter.

PURPOSE: Childhood onset speech fluency disorder (stuttering) is possibly related to dopaminergic dysfunction. Mesencephalic hyperechogenicity (ME) detected by transcranial ultrasound (TCS) might be seen as an indirect marker of dopaminergic dysfunction. We here determined whether adults who stutter since childhood (AWS) show ME. METHODS: We performed TCS in ten AWS and ten matched adults who never stuttered. We also assessed motor performance in finger tapping and in the 25 Foot Walking test. RESULTS: Compared to controls, AWS showed enlarged ME on either side. Finger tapping was slower in AWS. Walking cadence, i.e., the ratio of number of steps by time, tended to be higher in AWS than in control participants. DISCUSSION: The results demonstrate a motor deficit in AWS linked to dopaminergic dysfunction and extending beyond speech. Since iron deposits evolve in childhood and shrink thereafter, ME might serve as an easily quantifiable biomarker helping to predict the risk of persistency in children who stutter.

Microplotter-Printed On-Chip Combinatorial Library of Ink-Derived Multiple Metal Oxides as an "Electronic Olfaction" Unit.

Information about the surrounding atmosphere at a real timescale significantly relies on available gas sensors to be efficiently combined into multisensor arrays as electronic olfaction units. However, the array's performance is challenged by the ability to provide orthogonal responses from the employed sensors at a reasonable cost. This issue becomes more demanded when the arrays are designed under an on-chip paradigm to meet a number of emerging calls either in the internet-of-things industry or in situ noninvasive diagnostics of human breath, to name a few, for small-sized low-powered detectors. The recent advances in additive manufacturing provide a solid top-down background to develop such chip-based gas-analytical systems under low-cost technology protocols. Here, we employ hydrolytically active heteroligand complexes of metals as ink components for microplotter patterning a multioxide combinatorial library of chemiresistive type at a single chip equipped with multiple electrodes. To primarily test the performance of such a multisensor array, various semiconducting oxides of the p- and n-conductance origins based on pristine and mixed nanocrystalline MnOx, TiO2, ZrO2, CeO2, ZnO, Cr2O3, Co3O4, and SnO2 thin films, of up to 70 nm thick, have been printed over hundred µm areas and their micronanostructure and fabrication conditions are thoroughly assessed. The developed multioxide library is shown to deliver at a range of operating temperatures, up to 400 °C, highly sensitive and highly selective vector signals to different, but chemically akin, alcohol vapors (methanol, ethanol, isopropanol, and n-butanol) as examples at low ppm concentrations when mixed with air. The suggested approach provides us a promising way to achieve cost-effective and well-performed electronic olfaction devices matured from the diverse chemiresistive responses of the printed nanocrystalline oxides.

Finger Sequence Learning in Adults Who Stutter.

Originary neurogenic, non-syndromatic stuttering has been linked to a dysfunctional sensorimotor system. Studies have demonstrated that adults who stutter (AWS) perform poorly at speech and finger motor tasks and learning (e.g., Smits-Bandstra et al., 2006b; Namasivayam and van Lieshout, 2008). The high relapse rate after stuttering treatment could be a further hint for deficient motor learning and, in particular, for the limited generalization of the learned technique in daily communication. In this study, we tested generalization of finger sequence skills in AWS using an effector-dependent transfer task after a 24-h retention period. Additionally, we wanted to corroborate previous motor learning results in AWS for practice and retention: 16 AWS and 16 age-, sex-, and education-matched controls performed the task during four test sessions. Our results indicate that generalization performance in AWS was not inferior to that of fluent controls. In addition, we found, contrary to previous results, that AWS showed a steeper learning progress after practice and consolidation compared with controls. We suggest that with sufficient practice and a 24-h consolidation phase, AWS are able to retain the learned performance of tapping a five-item finger sequence as well as fluent controls in terms of speed and accuracy.

No Evidence for Dystonia-Like Sensory Overflow of Tongue Representations in Adults Who Stutter.

Persistent developmental stuttering (PDS) disrupts speech fluency in about 1% of adults. Although many models of speech production assume an intact sensory feedback from the speech organs to the brain, very little is actually known about the integrity of their sensory representation in PDS. Here, we studied somatosensory evoked potentials (SEPs) in adults who stutter (AWS), with the aim of probing the integrity of sensory pathways. In addition, we tested the processing of dual sensory input to address a putative link between stuttering and focal dystonia. In 15 AWS (aged 15-55 years; three females) and 14 matched fluent speaking adults (ANS), we recorded SEPs at C5' and C6' induced by stimulating separately or simultaneously the tongue or the cheek at the corner of the mouth. We determined latencies (N13, P19, and N27) and peak-to-peak amplitudes (N13-P19, P19-N27). We divided amplitudes from simultaneous stimulation by the sum of those from separate stimulation. Amplitude ratios did not differ between groups, indicating normal processing of dual sensory input. This does not support a clinical analogy between focal dystonia and persistent stuttering. SEP latencies as a measure of transmission speed in sensory pathways were significantly shorter in stuttering subjects than in fluent speaking participants, however, this might have been related to a trend for a height difference between groups, and was not confirmed in a replication dataset. In summary, we did not find evidence for dystonia-like sensory overflow of tongue representations in AWS.

Hand Motor Cortex Excitability During Speaking in Persistent Developmental Stuttering.

Persistent developmental stuttering (PDS) is a speech fluency disorder characterized by intermittent involuntary breakdowns of speech motor control, possibly related to motor cortex excitability. Whether motor cortex dysfunction extends into hand representations is unclear. We here studied task-dependent modulations of hand motor cortex excitability in 10 right-handed adults who stutter (AWS) and 13 age- and sex-matched fluent speaking control participants (ANS), covering a wide range of tasks in an exploratory study. Before, during and after a null speech/rest task, spontaneous speech, solo reading, chorus reading, singing, and non-verbal orofacial movements, transcranial magnetic stimulation was applied over the primary motor cortex and motor evoked potentials (MEPs) were recorded from the abductor digiti minimi muscle of either hand. In both groups, motor threshold was lower in the left than in the right motor cortex. During task performance, MEP amplitudes increased in both groups. A post hoc comparison of spontaneous speech and non-verbal orofacial movements yielded an interaction of group by task with AWS showing larger than ANS MEP amplitude increase in spontaneous speech, but a smaller than ANS MEP amplitude increase in non-verbal orofacial movements. We conclude that hemispheric specialization of hand motor representation is similar for both groups. Spontaneous speech as well as non-verbal orofacial movements are the orofacial tasks that merit further study. The excessive motor cortex facilitation could be reflecting a stronger activation of non-speech muscles during AWS's speech.

The Multisensor Array Based on Grown-On-Chip Zinc Oxide Nanorod Network for Selective Discrimination of Alcohol Vapors at Sub-ppm Range.

We discuss the fabrication of gas-analytical multisensor arrays based on ZnO nanorods grown via a hydrothermal route directly on a multielectrode chip. The protocol to deposit the nanorods over the chip includes the primary formation of ZnO nano-clusters over the surface and secondly the oxide hydrothermal growth in a solution that facilitates the appearance of ZnO nanorods in the high aspect ratio which comprise a network. We have tested the proof-of-concept prototype of the ZnO nanorod network-based chip heated up to 400 °C versus three alcohol vapors, ethanol, isopropanol and butanol, at approx. 0.2-5 ppm concentrations when mixed with dry air. The results indicate that the developed chip is highly sensitive to these analytes with a detection limit down to the sub-ppm range. Due to the pristine differences in ZnO nanorod network density the chip yields a vector signal which enables the discrimination of various alcohols at a reasonable degree via processing by linear discriminant analysis even at a sub-ppm concentration range suitable for practical applications.