Force Amplitude Modulation of Tongue and Hand Movements

Rapid, precise movements of the hand and tongue are necessary to complete a wide range of tasks in everyday life. However, the understanding of normal neural control of force production is limited, particularly for the tongue. Functional neuroimaging studies of incremental hand pressure production in healthy adults revealed scaled activations in the basal ganglia, but no imaging studies of tongue force regulation have been reported. The purposes of this study were (1) to identify the neural substrates controlling tongue force for speech and nonspeech tasks, (2) to determine which activations scaled to the magnitude of force produced, and (3) to assess whether positional modifications influenced maximum pressures and accuracy of pressure target matching for hand and tongue movements. Healthy older adults compressed small plastic bulbs in the oral cavity (for speech and nonspeech tasks) and in the hand at specified fractions of maximum voluntary contraction while magnetic resonance images were acquired. Volume of interest analysis at individual and group levels outlined a network of neural substrates controlling tongue speech and nonspeech movements. Repeated measures analysis revealed differences in percentage signal change and activation volume across task and effort level in some brain regions. Actual pressures and the accuracy of pressure matching were influenced by effort level in all tasks and body position in the hand squeeze task. The current results can serve as a basis of comparison for tongue movement control in individuals with neurological disease. Group differences in motor control mechanisms may help explain differential response of limb and tongue movements to medical interventions (as occurs in Parkinson disease) and ultimately may lead to more focused intervention for dysarthria in several conditions such as PD

Neural Control of Tongue Movements Across Effort Levels

Background A hallmark of Parkinson’s disease (PD) is a mismatch between the perceived effort and actual forces exerted during functional activities such as speech. Current evidence supports therapy to help reset this perception of effort, but the neurological underpinnings of such treatments are unclear. This study examined brain activity during tongue movements performed at varying levels of effort to determine (1) which brain areas are involved in each task, and (2) which areas, if any, scale in activation according to effort level. These results, considered with the neurological changes associated with PD, can be used to develop and refine treatment techniques for PD. Methods The structural and functional magnetic resonance (MR) data were previously collected from 20 healthy 40-60 year-old adults. Participants performed phoneme (speech sound) repetition and isometric tongue-to-palate presses while MR images were obtained. Ten datasets underwent whole brain analysis via SPM software to create a mask of shared activation. This mask was applied to the remaining 10 datasets to extract scaling data. Results/Conclusion Multiple areas including sensory, motor, and insular cortices were active during study tasks. The only area exhibiting statistically significant scaling was the left secondary sensorimotor cortex during the isometric tongue press. This area has been linked to processing of light touch, tactile attention, and somatosensory integration for voluntary skeletal movements. Additional activations were noted in the right insula, which is associated with motor control of speech and swallowing movements, as well as self-awareness

Neural Control of Tongue Movements Across Effort Levels

Background A hallmark of Parkinson’s disease (PD) is a mismatch between the perceived effort and actual forces exerted during functional activities such as speech. Current evidence supports therapy to help reset this perception of effort, but the neurological underpinnings of such treatments are unclear. This study examined brain activity during tongue movements performed at varying levels of effort to determine (1) which brain areas are involved in each task, and (2) which areas, if any, scale in activation according to effort level. These results, considered with the neurological changes associated with PD, can be used to develop and refine treatment techniques for PD. Methods The structural and functional magnetic resonance (MR) data were previously collected from 20 healthy 40-60 year-old adults. Participants performed phoneme (speech sound) repetition and isometric tongue-to-palate presses while MR images were obtained. Ten datasets underwent whole brain analysis via SPM software to create a mask of shared activation. This mask was applied to the remaining 10 datasets to extract scaling data. Results/Conclusion Multiple areas including sensory, motor, and insular cortices were active during study tasks. The only area exhibiting statistically significant scaling was the left secondary sensorimotor cortex during the isometric tongue press. This area has been linked to processing of light touch, tactile attention, and somatosensory integration for voluntary skeletal movements. Additional activations were noted in the right insula, which is associated with motor control of speech and swallowing movements, as well as self-awareness

Effect of Taste Stimuli on Swallowing Function in Persons with Traumatic Injuries

Background Swallowing disorders are prevalent and costly. As of now, there are limited therapeutic options available to treat them. Extant research in limited populations has suggested that swallowing mechanics can be improved by extremely sour liquids, but this has not been tested in traumatically injured populations. However, sour tastants are unpleasant, and more palatable taste mixtures have not been tested. Methods The quantitative data were extracted from an existing pool of de-identified video fluoroscopic swallowing studies (moving radiographs) obtained from traumatically injured young adults under another research protocol. Each participant completed swallows of custom-mixed plain, sour, and sweet-sour boluses. Positions of key anatomical landmarks at different stages of each swallow as well as area measures for pharyngeal residue after swallows were obtained. A standardized scale was used to describe any airway penetration of the bolus. Results were then compared across the three tastants. Results/Conclusion The tastants affected the amount of residue that remained within the vallecular and piriform spaces on each trial. The residue in both the vallecular and piriform cavities was consistently lower (suggesting a more efficient swallow) when a sweet-sour bolus was swallowed. The amount of residue remaining after a sour or plain bolus was swallowed varies between the two cavities. However, the degree of airway penetration/aspiration from each swallow did not appear to have a direct relationship with either the tastant type nor the residue left behind

Tolerance of the VocaLog Vocal Monitor by Healthy Persons and Individuals With Parkinson Disease

Objective: To assess subject tolerance of extended use of the VocaLogTM vocal monitor (VM), a device marketed to log calibrated decibel sound pressure level. Study Design: Prospective between-subjects design including two age- and sex-matched groups: individuals with Parkinson disease (IWPD) and healthy persons. Methods: After an initial session to calibrate the device and demonstrate its use, participants wore the VM during waking hours for five consecutive days. At a second visit to return the VM, participants completed a survey and a short interview regarding their experience with and perceptions of the device. Results: Those with PD and control subjects reported relatively few issues with use of the VM. There were no group differences regarding convenience, others’ reactions, technical issues, or future participation in similar studies. Participants with PD indicated similar frequency of discomfort issues but higher severity ratings for discomfort during VM use compared with healthy participants. Conclusions: The VocaLogTM offers a method to monitor vocal loudness during everyday activities for several consecutive days. The device was well tolerated by participants from both groups. IWPD reported greater discomfort than controls, possibly reflecting altered sensory perceptions associated with PD. The current data offer some reassurance that this VM can be tolerated by both healthy persons and those with PD for clinical and research purposes

Tolerance of the VocaLog Vocal Monitor by Healthy Persons and Individuals With Parkinson Disease

Objective: To assess subject tolerance of extended use of the VocaLogTM vocal monitor (VM), a device marketed to log calibrated decibel sound pressure level. Study Design: Prospective between-subjects design including two age- and sex-matched groups: individuals with Parkinson disease (IWPD) and healthy persons. Methods: After an initial session to calibrate the device and demonstrate its use, participants wore the VM during waking hours for five consecutive days. At a second visit to return the VM, participants completed a survey and a short interview regarding their experience with and perceptions of the device. Results: Those with PD and control subjects reported relatively few issues with use of the VM. There were no group differences regarding convenience, others’ reactions, technical issues, or future participation in similar studies. Participants with PD indicated similar frequency of discomfort issues but higher severity ratings for discomfort during VM use compared with healthy participants. Conclusions: The VocaLogTM offers a method to monitor vocal loudness during everyday activities for several consecutive days. The device was well tolerated by participants from both groups. IWPD reported greater discomfort than controls, possibly reflecting altered sensory perceptions associated with PD. The current data offer some reassurance that this VM can be tolerated by both healthy persons and those with PD for clinical and research purposes

Testing of the VocaLog Vocal Monitor

Objective. To elucidate capabilities and limitations of the VocaLog, a device marketed to log-calibrated dB sound pressure level (SPL). Study Design. The study design varied depending on the experiment. All were prospective. Some were case series, and others were cohort studies without controls. Method. Experiments were conducted to determine (1) whether the VocaLog logged phonatory activity and silence when it should, (2) if nonphonatory activities were detected, (3) correlation of VocaLog dB values to an external sound level meter (SLM), and (4) accuracy of phonation time (PT) and speaking time (ST) estimates from the VocaLog. Results. Silence and phonatory activity were logged as such nearly 100% of the time. Nonphonatory activities were sometimes detected as dB values, including coughs, throat clear, belching, and swallows. The dB values from the VocaLog were strongly correlated with dB SPL from an external SLM. When on the neck, the device rarely picked up external sounds when the external noise was between 85 and 103 dB SPL. The VocaLog gave a reasonable estimate of ST but overestimated PT. Conclusions. Overall, the VocaLog holds promise as means of indexing vocal loudness via calibrated dBSPL levels. However, some nonphonatory activity is also likely to be logged. The device provides a reasonable estimate of ST, but not PT

Testing of the VocaLog Vocal Monitor

Objective. To elucidate capabilities and limitations of the VocaLog, a device marketed to log-calibrated dB sound pressure level (SPL). Study Design. The study design varied depending on the experiment. All were prospective. Some were case series, and others were cohort studies without controls. Method. Experiments were conducted to determine (1) whether the VocaLog logged phonatory activity and silence when it should, (2) if nonphonatory activities were detected, (3) correlation of VocaLog dB values to an external sound level meter (SLM), and (4) accuracy of phonation time (PT) and speaking time (ST) estimates from the VocaLog. Results. Silence and phonatory activity were logged as such nearly 100% of the time. Nonphonatory activities were sometimes detected as dB values, including coughs, throat clear, belching, and swallows. The dB values from the VocaLog were strongly correlated with dB SPL from an external SLM. When on the neck, the device rarely picked up external sounds when the external noise was between 85 and 103 dB SPL. The VocaLog gave a reasonable estimate of ST but overestimated PT. Conclusions. Overall, the VocaLog holds promise as means of indexing vocal loudness via calibrated dBSPL levels. However, some nonphonatory activity is also likely to be logged. The device provides a reasonable estimate of ST, but not PT

Comparing Taste Perception Across Modalities in Healthy Adults: Liquids Versus Dissolvable Taste Strips

Taste stimulation has rehabilitative value in dysphagia management, as it activates salient underlying afferent pathways to swallowing which may evoke feedforward effects on swallow biomechanics. Despite its potential beneficial effects on swallow physiology, taste stimulation’s clinical application is limited for persons unsafe to orally consume food/liquid. This study aimed to create edible, dissolvable taste strips matched to flavor profiles previously used in research assessing taste’s effects on swallowing physiology and brain activity, and to evaluate how similar their perceived intensity and hedonic, or palatability, ratings were between their liquid counterparts. Plain, sour, sweet–sour, lemon, and orange flavor profiles were custom-made in taste strips and liquid modalities. The generalized Labeled Magnitude Scale and hedonic generalized Labeled Magnitude Scale were used to assess intensity and palatability ratings for flavor profiles in each modality. Healthy participants were recruited and stratified across age and sex. Liquids were rated as more intense than taste strips; however, there was no difference in palatability ratings between the modalities. There were significant differences across flavor profiles in intensity and palatability ratings. Collapsed across liquid and taste strip modalities, pairwise comparisons revealed all flavored stimuli were rated as more intense than the plain profile, sour was perceived as more intense and less palatable than all other profiles, and orange was rated as more palatable than sour, lemon, and plain tastants. Taste strips have useful implications for dysphagia management, as they could offer safe and patient-preferred flavor profiles to potentially provide advantageous swallowing and neural hemodynamic responses

Endoscopic and Stroboscopic Presentation of the Larynx in Male-to-Female Transsexual Persons

Background. Male-to-female transsexual (MFT) persons often attempt to produce a female-sounding voice as part of the transition process. Endoscopic and stroboscopic data about how they accomplish this with an anatomically male larynx are lacking. Objectives. To describe vocal fold activity in MFT persons producing their feminine voice and identify signs of vocal misuse or hyperfunction in MFT speakers, if any. Study Design. Prospective, nonrandomized, descriptive study of a convenience sample of MFT persons. Methods. All MFT persons had endoscopic and stroboscopic procedures completed. Images were rated on a range of parameters by two experienced voice therapists to derive the descriptions. MFT participant self-report of voice use/ symptoms and listener identifications of speaker gender from a perceptual task were also obtained. Results. Incomplete glottal closure was common with a posterior glottal gap predominating. Phase closure ratios also were skewed toward more ‘‘open’’ time for nearly half of the group. Supraglottic constriction was seen to varying degrees in all, and voice complaints were reported by 67% of the group. Conclusions. MFT speakers who reported a ‘‘passing’’ feminine voice had glottal gap configurations more similar to anatomic females than males and tended toward more open phase closure ratios, perhaps consistent with breathy or soft voice production. Indications of vocal hyperfunction were present for all participants either by self-report or on the laryngeal examination