Relative fundamental frequency (RFF) is a promising acoustic measure for evaluating voice disorders. Yet, the accuracy of the current RFF algorithm varies across a broad range of vocal signals. The authors investigated how fundamental frequency (fo) estimation and sample characteristics impact the relationship between manual and semi-automated RFF estimates. Acoustic recordings were collected from 227 individuals with and 256 individuals without voice disorders. Common fo estimation techniques were compared to the autocorrelation method currently implemented in the RFF algorithm. Pitch strength-based categories were constructed using a training set (1158 samples), and algorithm thresholds were tuned to each category. RFF was then computed on an independent test set (291 samples) using category-specific thresholds and compared against manual RFF via mean bias error (MBE) and root-mean-square error (RMSE). Auditory-SWIPE′ for fo estimation led to the greatest correspondence with manual RFF and was implemented in concert with category-specific thresholds. Refining fo estimation and accounting for sample characteristics led to increased correspondence with manual RFF [MBE = 0.01 semitones (ST), RMSE = 0.28 ST] compared to the unmodified algorithm (MBE = 0.90 ST, RMSE = 0.34 ST), reducing the MBE and RMSE of semi-automated RFF estimates by 88.4% and 17.3%, respectively.

Purpose We empirically assessed the results of computational optimization and prediction in communication interfaces that were designed to allow individuals with severe motor speech disorders to select phonemes and generate speech output. Method Interface layouts were either random or optimized, in which phoneme targets that were likely to be selected together were located in proximity. Target sizes were either static or predictive, such that likely targets were dynamically enlarged following each selection. Communication interfaces were evaluated by 36 users without motor impairments using an alternate access method. Each user was assigned to 1 of 4 interfaces varying in layout and whether prediction was implemented (random/static, random/predictive, optimized/static, optimized/predictive) and participated in 12 sessions over a 3-week period. Six participants with severe motor impairments used both the optimized/static and optimized/predictive interfaces in 1–2 sessions. Results In individuals without motor impairments, prediction provided significantly faster communication rates during training (Sessions 1–9), as users were learning the interface target locations and the novel access method. After training, optimization acted to significantly increase communication rates. The optimization likely became relevant only after training when participants knew the target locations and moved directly to the targets. Participants with motor impairments could use the interfaces with alternate access methods and generally rated the interface with prediction as preferred. Conclusions Optimization and prediction led to increases in communication rates in users without motor impairments. Predictive interfaces were preferred by users with motor impairments. Future research is needed to translate these results into clinical practice. Supplemental Material https://doi.org/10.23641/asha.8636948

This study details the intended and unintended consequences of pitch shifting with the commercially available Eventide Eclipse. Method: Ten vocally healthy participants (M = 22.0 years; 6 cisgender females, 4 cisgender males) produced a sustained /ɑ/, creating an input signal. This input signal was processed in near real time by the Eventide Eclipse to create an output signal that was either not shifted (0 cents), shifted +100 cents, or shifted −100 cents. Shifts occurred either throughout the entire vocalization or for a 200-ms period after vocal onset. Results: Input signals were compared to output signals to examine potential changes. Average pitch-shift magnitudes were within 1 cent of the intended pitch shift. Measured pitch-shift length for intended 200-ms shifts was between 5.9% and 21.7% less than expected, based on the portion of shift selected for measurement. The delay between input and output signals was an average of 11.1 ms. Trials shifted +100 cents had a longer delay than trials shifted −100 or 0 cents. The first 2 formants (F1, F2) shifted in the direction of the pitch shift, with F1 shifting 6.5% and F2 shifting 6.0%. Conclusions: The Eventide Eclipse is an accurate pitchshifting hardware that can be used to explore voice and vocal motor control. The pitch-shifting algorithm shifts all frequencies, resulting in a subsequent change in F1 and F2 during pitch-shifted trials. Researchers using this device should be mindful of stimuli selection to avoid confusion during data interpretation.

Background As a potential neurophysiology‐based biomarker of cortical neuronal network integrity, visually evoked steady‐state oscillations (SSVEPs) are investigated in healthy young and elderly subjects, and mild cognitive impaired (MCI) and Alzheimer’s disease (AD) patients. Based on recent findings from the Li‐Huei Tsai Laboratory (Picower Institute, MIT) showing that 40 Hz audio/visual stimulation reverses AD‐related pathologies in transgenic mice, we are evaluating the effects of 40 Hz audio/visual stimulation on brain neurophysiology in healthy subjects, and MCI and AD patients (together with clinical trials assessing impact on severity of clinical symptoms and Aβ PET signals) at Cognito Therapeutics. Method We are testing SSVEPs, including 15, 30 and 40 Hz light stimulations, and evoked steady state oscillations in response to combined 40 Hz audio/visual stimulation using 128 or 64 channel EEG recordings, respectively. We analyze phase‐locked evoked potentials, inter‐trial coherence, induced oscillations and network coherence in young subjects, MCI and AD patients and age‐matched healthy elderly individuals. Result SSVEPs have been observed in healthy subjects and MCI/AD patients in response to 3 second flashing light using 15, 30 and 40 Hz stimulation frequencies. High test/re‐test reliability has been established in healthy young subjects. Compared to healthy young subjects (< 30 years), diminished inter‐trial coherence in healthy elderly (> 65 years) subjects, and impaired sensory responses in MCI and AD patients were found to light stimulation. Simultaneous audio/visual 40 Hz stimulation, using Cognito Stimulation System elicited 40 Hz entrainment of cortical activity over the entire 1‐hour session in healthy subjects, MCI and AD patients, without adverse events either during or following SSEVP. Cortical 40 Hz entertainment was accompanied with high‐intensity alpha oscillation. Following the audio/visual stimulation, the augmented alpha band power was associated with increased alpha coherence between fronto‐occipital and fronto‐temporal regions. Conclusion Reliable 40 Hz steady‐state oscillations can be elicited and maintained in MCI and AD patients, providing an opportunity to evaluate symptomatic and disease‐modifying effects of this therapy. Detecting disease relevant and individual SSVEP abnormalities can support precision medicine by customizing therapy.

Background Alzheimer’s disease (AD) patients exhibit distorted excitatory‐inhibitory balance of neuronal activity, leading to accelerated worsening of functional and cognitive abilities. Improving abnormal neuronal synchrony by long‐term non‐invasive, gamma sensory stimulation at 40 Hz in transgenic mice carrying pathological AD human genes has been shown to beneficially affect neural activity and improve learning and memory. In the present translational clinical trial, the effects of gamma sensory stimulation on cognition and global function were evaluated in AD patients using an at‐home therapy device (Cognito Therapeutics, Cambridge, MA). Method The phase I/II randomized, controlled, single‐blinded multi‐center clinical trial (Overture study; NCT03556280) evaluated safety, adherence rates and efficacy of gamma sensory stimulation therapy in patients with mild to moderate Alzheimer’s disease (MMSE 14‐26, inclusive). The 6‐month trial included treatment and sham groups receiving daily, one‐hour sensory stimulation but only participants in the treatment group were exposed to 40Hz auditory and visual stimulations. During the trial, cognitive functions were measured by Alzheimer's Disease Assessment Scale (ADAS‐Cog), Mini‐Mental State Examination (MMSE), and Clinical Dementia Rating Sum of Boxes (CDR‐SB). In order to align assessment data in time to study events (therapy start and end) and account for variable study visit intervals at start and end of therapy period, cognitive measures were calculated on a per‐patient basis by a model of AD‐related cognitive decline derived from a large‐scale dataset. Finally, adjusted cognitive scores were compared between the two groups. Result The trial has been completed by 33 and 19 patients in the treatment and sham groups, respectively. Daily therapy of gamma sensory stimulation was well tolerated, confirming safety and high adherence. The three independent cognitive tests demonstrated a diminished cognitive decline in the treatment group compared to the sham group. Final analysis results from MMSE, ADAS‐Cog, CDR‐SB and Integrated Alzheimer's Disease Rating Scale (iADRS) will be presented at the meeting. Conclusion The present findings, together with the established safety profile, functional benefit, and improvement in sleep justify further evaluation of gamma sensory stimulation in AD patients.