Age differences in the motor control of speech: An fMRI study of healthy aging.

To explore age differences in speech production in relation to orofacial physiology. Cross-sectional quasi-experimental group study. General community. Physically and cognitively healthy volunteers recruited from the community (N = 30), including 15 young (18-39) and 15 older (66-85) adults. Accuracy and speech rate were calculated during the production of sequences of syllables containing oral vowels, nasal vowels, or both. Lip and tongue muscular strength, muscular endurance, and tactile sensitivity were also measured. Older adults had a slower speech rate than younger adults and greater difficulty articulating nasal vowels. Analyses revealed that age-related decline in lip endurance is associated with decline in accuracy during speech production. Older adults are not just slower than younger adults, they also exhibit specific articulatory difficulties. Although many physiological changes in orofacial functions occur in aging, only muscular endurance of the lips is related to age-related differences in speech production. This information is important for the development of speech interventions targeting older adults with speech motor disorders.

Gene expression in cells of the central nervous system

Estradiol and progesterone vary along the menstrual cycle and exert opposite effects on a variety of neurotransmitter systems. However, few studies have addressed menstrual cycle-dependent changes in the brain. In the present study we investigate menstrual cycle changes in brain activation and connectivity patterns underlying cognition. Thirty-six naturally cycling women underwent functional MRI during two cognitive tasks: spatial navigation and verbal fluency. While no significant performance differences were observed along the menstrual cycle, the changes in brain activation patterns are strikingly similar during both tasks. Irrespective of the task, estradiol boosts hippocampal activation during the pre-ovulatory cycle phase and progesterone boosts fronto-striatal activation during the luteal cycle phase. Connectivity analyses suggest that the increase in right-hemispheric frontal activation is the result of inter-hemispheric decoupling and is involved in the down-regulation of hippocampal activation.

Changes in brain activation patterns after physiotherapy program: A preliminary randomized controlled trial study after Postural Reconstruction® and stretching programs

Investigations of the differences in movement speed over the age span, childhood to early adulthood, have typically confounded age with size differences which bring about mechanical differences in the task. The present study investigated the effect on arm movement time of confounding age and limb length. Young adults and children 7 to 9 yr. of age were tested over a distance proportional to their arm length. Despite moving over a proportionally shorter distance, the children were significantly slower than the adults, suggesting that age differences in performance are not solely attributable to size differences among subjects.

Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function (i.e., primary motor cortex, premotor area, posterior parietal cortex) showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.

Speech motor control and orofacial point pressure sensation in adults with ADHD

Introduction: Broca’s aphasia is one of the types of non-fluent aphasia that its main feature is imprecise speech sound productions. Different surveys have shown that patients with Broca’s aphasia have defects which can affect sound structure in their speech output, but it is less clear that the nature of these errors is an impairment in the selection and planning or articulatory implementation. Determination of the nature of speech errors in these patients is very important and necessary in order to recognize the basic mechanisms which are effective in creating these errors. The purpose of this descriptive study is to a review of studies which have investigated the nature of errors in acoustic ways in these patients. Materials and Method: This descriptive study has been conducted by searching for the following keywords: “acoustic parameters, nature of errors, Broca’s aphasia, speech motor control and Speech errors. The following databases have also been used to conduct searches: web of knowledge, science direct, Google scholar and PubMed. Results: Individuals with Broca’s aphasia possess defects including difficulties in timing, articulatory coordination, and laryngeal control in the field of speech motor control which are as a result of defects in the coordination, Timing of movements and articulatory implementation to produce the target segment Conclusion: Recent researches based on Acoustic parameters of the speech production patterns suggest that the main feature of speech impairment of people with Broca’s aphasic is a severe phonetic disorder relating to the articulator implementation of the selected and planned segments of speech. Keywords: Broca's aphasia, Speech motor control, Speech errors, acoustic parameters.

Aural Habilitation Update: The Role of Speech Production Skills of Infants and Children With Hearing Loss

Age differences in the control of a precision reach to grasp task within a desktop virtual environment

Characteristics of Psychotic Patients With Foreign Accent Syndrome

Movement time (MT) is one of the most important variables influencing the way we control our movements. A few previous studies have generally found that MT reduces with reaction time testing during exercise. However, limited evidence exists concerning change in MT following an acute bout of exercise. Our purpose was to investigate the effect of an acute bout of aerobic exercise on movement time as assessed by a Fitts’ Law task. We also sought to determine if exercise would further lower MT during the more difficult task conditions compared with rest. Nineteen (12 male, 7 female) volunteers (19–28 yrs) completed a computerized paired serial pointing task to measure movement time before and after rest (R) and an acute bout of moderate aerobic exercise (E) using a within subjects crossover design. Comparisons between exercise and rest conditions were made to determine if there were differences in movement time. Exercise significantly reduced MT compared with rest. Movement time was reduced by an average of 208 ms following exercise compared with 108 ms following rest. Exercise did not further lower MT during the more difficult task conditions. These results suggest that an acute bout of aerobic exercise reduces movement time which is an important component of motor control. Further studies are needed to determine the duration of the effect as well as the optimum duration and intensity of exercise.

Sensory–motor networks involved in speech production and motor control: An fMRI study

Defining Speech and Language Fluency Profiles in Children with and without Family History of Stuttering, before and after the Onset of Stuttering: Preliminary Findings

Purpose While the speech motor system is sensitive to feedback perturbations, sensory feedback does not seem to be critical to speech motor production. How the speech motor system is able to be so flexible in its use of sensory feedback remains an open question. Method We draw on evidence from a variety of disciplines to summarize current understanding of the sensory systems' role in speech motor control, including both online control and motor learning. We focus particularly on computational models of speech motor control that incorporate sensory feedback, as these models provide clear encapsulations of different theories of sensory systems' function in speech production. These computational models include the well-established directions into velocities of articulators model and computational models that we have been developing in our labs based on the domain-general theory of state feedback control (feedback aware control of tasks in speech model). Results After establishing the architecture of the models, we show that both the directions into velocities of articulators and state feedback control/feedback aware control of tasks models can replicate key behaviors related to sensory feedback in the speech motor system. Although the models agree on many points, the underlying architecture of the 2 models differs in a few key ways, leading to different predictions in certain areas. We cover key disagreements between the models to show the limits of our current understanding and point toward areas where future experimental studies can resolve these questions. Conclusions Understanding the role of sensory information in the speech motor system is critical to understanding speech motor production and sensorimotor learning in healthy speakers as well as in disordered populations. Computational models, with their concrete implementations and testable predictions, are an important tool to understand this process. Comparison of different models can highlight areas of agreement and disagreement in the field and point toward future experiments to resolve important outstanding questions about the speech motor control system.