Sudden onset of excessive repetitions in the speech of a patient with multiple sclerosis: A case report

This report provides a detailed analysis of excessive part- and whole-word repetitions in the speech of a 36-year-old male patient hospitalized for treatment of multiple sclerosis (MS) who also exhibited concurrent language and prosodic disturbances. Shortly following his hospitalization, a magnetic resonance imaging examination revealed plaques in the white matter of the medulla, cerebellum, basal ganglion, and periventricular white matter. His speech strongly resembled apractic speech patterns, chiefly syllable segregation. The source of data collected for this study was seven tape-recorded speech samples containing 2536 words spoken in 32.75 min, diagnostic reports, and clinical notes of 27 biweekly speech therapy sessions across a 5-month period. This report focused on an analysis of variables associated with the patient's part- and whole-word repetitions, and it was concluded that they were used as a compensatory device to procure additional time to articulate complex syllables. A brief critique of the therapeutic procedures used for treating his speech problem is also presented.

Educational objectives: The reader will learn about and be able to describe (1) the effects of MS on speech and language; (2) the kinds of data that were gathered to account for this patient's sudden onset of speech and language disorders; and (3) the findings that led them to conclude that his excessive repetitions were compensatory behaviors.     

Adaptation to continuous perturbation of balance: progressive reduction of postural muscle activity with invariant or increasing oscillations of the center of mass depending on perturbation frequency and vision conditions

We investigated the adaptation of balancing behavior during a continuous, predictable perturbation of stance consisting of 3-min backward and forward horizontal sinusoidal oscillations of the support base. Two visual conditions (eyes-open, EO; eyes-closed, EC) and two oscillation frequencies (LF, 0.2 Hz; HF, 0.6 Hz) were used. Center of Mass (CoM) and Center of Pressure (CoP) oscillations and EMG of Soleus (Sol) and Tibialis Anterior (TA) were recorded. The time course of each variable was estimated through an exponential model. An adaptation index allowed comparison of the degree of adaptation of different variables. Muscle activity pattern was initially prominent under the more challenging conditions (HF, EC and EO; LF, EC) and diminished progressively to reach a steady state. At HF, the behavior of CoM and CoP was almost invariant. The time-constant of EMG adaptation was shorter for TA than for Sol. With EC, the adaptation index showed a larger decay in the TA than Sol activity at the end of the balancing trial, pointing to a different role of the two muscles in the adaptation process. At LF, CoM and CoP oscillations increased during the balancing trial to match the platform translations. This occurred regardless of the different EMG patterns under EO and EC. Contrary to CoM and CoP, the adaptation of the muscle activities had a similar time-course at both HF and LF, in spite of the two frequencies implying a different number of oscillation cycles. During adaptation, under critical balancing conditions (HF), postural muscle activity is tuned to that sufficient for keeping CoM within narrow limits. On the contrary, at LF, when vision permits, a similar decreasing pattern of muscle activity parallels a progressive increase in CoM oscillation amplitude, and the adaptive balancing behavior shifts from the initially reactive behavior to one of passive riding the platform. Adaptive balance control would rely on on-line computation of risk of falling and sensory inflow, while minimizing balance challenge and muscle effort. The results from this study contribute to the understanding of plasticity of the balance control mechanisms under posture-challenging conditions.     

Postural Asymmetries in Response to Holding Evenly and Unevenly Distributed Loads During Self-Selected Stance

The authors examined postural asymmetries during quiet stance and while holding evenly or unevenly distributed loads. Right-hand dominant subjects preferentially loaded their right lower limb when holding no load or a load evenly distributed in both hands, but no differences in center of pressure (CoP) were observed between the left and right limbs. However, longer CoP displacement was observed under the preferentially loaded limb, which may reflect a functional asymmetry that allows quick movement of one limb in response to a potential perturbation. When a load was held only in the nondominant hand, sample entropy decreased in the left (loaded) limb but increased in the right (unloaded) limb, suggesting the unloaded foot compensated for a loss of control flexibility in the loaded foot.     

Phase Correction Following a Perturbation in Sensorimotor Synchronization Depends on Sensory Information

In models of sensorimotor synchronization, it is generally assumed that phase correction occurs in response to information about sensorimotor asynchrony or relative phase. Without such feedback, a phase perturbation in the motor activity should not be followed by phase correction. Alternatively, internally generated temporal expectations could provide a basis for phase correction in the absence of feedback. To test those hypotheses, the author conducted an experiment in which participants (N = 8) tapped their finger in synchrony with isochronous auditory sequences containing a single shifted event onset, after which there could be a gap of up to 3 missing events. Participants were instructed to not react to the shifted event and to continue tapping regularly during any gap. The shifted event caused an involuntary phase shift of the following tap. The shift was corrected if the sequence continued, but during a gap, the shift persisted without correction. Those results confirm that sensory feedback is necessary for phase correction to occur.     

Postural Control Complexity and Fatigue in Minimally Affected Individuals with Multiple Sclerosis

This study investigated changes in postural control complexity in people with multiple sclerosis (PwMS) before and after a fatigue protocol. Thirteen minimally affected PwMS (1.53 ± 1.03- Expanded Disability Status Scale) and 12 non-MS controls. Postural test included quiet stance on a force platform under two visual conditions (saccades and fixation) before and after a fatigue protocol. Postural complexity was assessed through the multiscale entropy. A three-way ANOVA showed a main effect of fatigue in the medial-lateral direction (p <0.007), with fatigue protocol reducing postural complexity in both groups. No differences were found between groups or visual conditions. Minimally affected PwMS demonstrated similar postural complexity compared with non-MS controls under both visual tasks and showed similar decrements in postural complexity as a result of fatigue.     

Psychological Risk Factors of Sudden Cardiac Arrest

This study tested the hypotheses that Vital Exhaustion (VE) increases the risk of sudden cardiac arrest (SCA) and that non-expression of emotions modifies the risk of VE. Data came from 99 victims of SCA and 103 healthy controls matched for gender and age. Victims of SCA were more often assessed as exhausted and as being closed by their family members than controls, the estimated relative risks being 2.81 (95% CI 1.1-7.3) and 2.28 (95% CI 1.1-4.6), respectively. No significant interaction between exhaustion and being closed on the risk of SCA was observed. These findings indicate that a state of exhaustion and being closed belong to the risk indicators of SCA.     

Anticipatory Postural Adjustments for Altering Direction During Walking

The authors examined how individuals adapt their gait and regulate their body configuration before altering direction during walking. Eight young adults were asked to change direction during walking with different turning angles (0deg;, 45deg;, 90deg;), pivot foot (left, right), and walking speeds (normal and fast). The authors used video and force platform systems to determine participants' whole-body center of mass and the center of pressure during the step before they changed direction. The results showed that anticipatory postural adjustments occurred during the prior step and occurred earlier for the fast walking speed. Anticipatory postural adjustments were affected by all 3 variables (turn angle, pivot foot, and speed). Participants leaned backward and sideward on the prior step in anticipation of the turn. Those findings indicate that the motor system uses central control mechanisms to predict the required anticipatory adjustments and organizes the body configuration on the basis of the movement goal.     

Perturbations of Human Posture

Leg muscle EMG responses and cerebral evoked potentials (CP), elicited by perturbations of stance while on a treadmill with split belts, were analyzed in order to study the relationship between compensatory leg muscle responses and afferent input to supraspinal centers. Various conditions of perturbation were used to establish the extent to which compensatory EMG responses and CPs show congruent behavior. Four different treadmill acceleration rates were applied in three different conditions (unilateral perturbation, directed forward or backward; bilateral perturbation, directed forward or backward; and opposing bilateral perturbation). EMG responses and CPs showed parallel increases in amplitude with increasing displacement velocity. The EMG responses showed distinct differences, predominantly in the response amplitude, between the different perturbation conditions, whereas the CPs were affected only to a minor degree. Tibialis anterior EMG responses were more closely related to the CP following forward perturbation than the corresponding gastrocnemius responses were to the CP following backward perturbation.

We conclude that the EMG responses are more closely related than the CPs to displacement parameters and suggest that this is due to the further spinal processing of the afferent input needed to generate an appropriate EMG response. The closer relationship between the tibialis anterior response and CP may reflect a predominant central representation and control of tibialis anterior activation in the regulation of posture. The functional implications of these findings are discussed.     

Sudden gains in cognitive behavioral treatment for depression: when do they occur and do they matter?

Despite the use of efficacious treatments for depression, individuals differ in both the degree to which they recover and the rate at which recovery occurs. Tang and colleagues found that depressed patients who had sudden improvements in their symptomatology not only maintained these gains, but also enjoyed more improvement and higher rates of recovery than those without sudden gains (J. Consulting Clin. Psychol. 67(6) (1999) 894; J. Consulting Clin. Psychol. 70(2) (2002) 444). Our study examined the role of sudden gains in a cognitive-behavioral group treatment for depression. Results indicated that 41.9% of patients experienced sudden gains. Furthermore, sudden gains occurring in the first third of treatment appear to have special importance. Participants enjoying early sudden gains had significantly larger changes in depressive symptom scores over the course of treatment than those without sudden gains and were marginally more likely to be treatment responders compared to those without early sudden gains. In contrast to Tang and DeRubeis (J. Consulting Clin. Psychol. 67(6) (1999) 894), however, sudden gains were not associated with cognitive changes.     

The Effects of Relaxation and Postural Training on External Perception: Improvement of Visual Acuity, Visual Field, and Hearing Acuity

This study examined the effects of muscular relaxation and postural training on external perception using a visual acuity test, a visual field test, and a hearing acuity test. Eighteen undergraduate students were randomly assigned to experimental and control groups. The experimental group underwent muscular relaxation and postural training. Each subject in this group was administered the tests before and after the training. Each subject in the control group carried out the tests before and after participating in a 30-min conversation with the experimenter. On all three tests, the experimental group improved significantly more than the control group.