Hitoshi Kagaya

Dynamic change in hyoid muscle length associated with trajectory of hyoid bone during swallowing: analysis using 320-row area detector computed tomography

Research on muscle activation patterns during swallowing has been limited. Newly developed 320-row area detector computed tomography (320-ADCT) has excellent spatial and temporal resolution, which facilitates identification of laryngopharyngeal structures and quantitative kinematic analysis of pharyngeal swallowing. We investigated muscle activity patterns by observing the changes in length of hyoid muscles. 320-ADCT was performed in 26 healthy males while swallowing. The following parameters were analyzed three-dimensionally: 1) origins and insertions of the stylohyoid, anterior and posterior digastric, mylohyoid, geniohyoid, and thyrohyoid muscles; and 2) movement of the hyoid bone. The stylohyoid, posterior digastric, and mylohyoid muscles began to shorten simultaneously during the initial stage of swallowing. The shortening of these muscles occurred during the upward movement of the hyoid bone. Subsequently, the geniohyoid, thyrohyoid, and anterior digastric muscles began to shorten, synchronizing with the forward movement of the hyoid bone. A significant correlation was observed between the shortened muscle lengths of the stylohyoid, posterior digastric, and mylohyoid muscles and the upward movement of the hyoid bone (r = 0.45-0.65). A correlation was also observed between the shortened muscle length of the geniohyoid muscle and the forward movement of the hyoid bone (r = 0.61). In this study, the sequence of muscle activity during pharyngeal swallowing remained constant. Serial shortening of the hyoid muscles influenced the trajectory of the hyoid bone. The stylohyoid, posterior digastric, and mylohyoid muscles initiated the swallowing reflex and contributed to upward movement of the hyoid bone. The geniohyoid is a key muscle in the forward movement of the hyoid bone.

Preliminary Trial of Postural Strategy Training Using a Personal Transport Assistance Robot for Patients With Central Nervous System Disorder

OBJECTIVE To examine the efficacy of postural strategy training using a personal transport assistance robot (PTAR) for patients with central nervous system disorders. DESIGN Single-group intervention trial. SETTING Rehabilitation center at a university hospital. PARTICIPANTS Outpatients (N=8; 5 men, 3 women; mean age, 50±13y) with a gait disturbance (mean time after onset, 34±29mo) as a result of central nervous system disorders were selected from a volunteer sample. INTERVENTIONS Two methods of balance exercise using a PTAR were devised: exercise against perturbation and exercise moving the center of gravity. The exercises were performed twice a week for 4 weeks. MAIN OUTCOME MEASURES Preferred and tandem gait speeds, Functional Reach Test, functional base of support, center of pressure (COP), muscle strength of lower extremities, and grip strength were assessed before and after the completion of the exercise program. After the exercise program, enjoyment of exercise was investigated via a visual analog scale questionnaire. RESULTS After the program, statistically significant improvements were noted for tandem gait speeds (P=.009), Functional Reach Test (P=.003), functional base of support (P=.014), and lower extremity muscle strength (P<.001-.042). On the other hand, preferred gait speeds (P=.151), COP (P=.446-.714), and grip power (P=.584) did not change. Finally, subjects rated that this exercise was more enjoyable than traditional balance exercises. CONCLUSIONS Dynamic balance and lower extremity muscle strength were significantly improved in response to postural strategy training with the PTAR. These results suggest that postural strategy training with the PTAR may contribute to fall prevention of patients with a balance disorder.

Hyoid Bone and Larynx Movements During Electrical Stimulation of Motor Points in Laryngeal Elevation Muscles: A Preliminary Study

Objectives:  This study aimed to determine the laryngeal elevation muscle motor points, evaluate the movement of hyoid bone and larynx during stimulation of the motor points, and examine the potential for treating severe dysphagia by functional electrical stimulation.

Simple Swallowing Provocation Test Has Limited Applicability as a Screening Tool for Detecting Aspiration, Silent Aspiration, or Penetration

A number of tests for evaluating dysphagia without using videofluoroscopic examination of swallowing (VF) or videoendoscopic evaluation of swallowing (VE) have been developed. The simple swallowing provocation test (SSPT) is unique because it is performed while in a supine position and does not require the patient’s cooperation. However, whether the SSPT detects aspiration or penetration correctly is unclear because its validity determined by VF or VE has not been evaluated. Therefore, we determined the sensitivity, specificity, and predictive accuracy of SSPT followed by VF in 45 patients. The sensitivities of the first-step and the second-step SSPT for the detection of aspiration, silent aspiration, or penetration were 72–75% and 13–17%, respectively; the specificities of the first-step and the second-step SSPT were 38–44% and 80–89%, respectively; and the predictive accuracies of the first-step and the second-step SSPT were 58–67% and 31–49%, respectively. These data suggest that SSPT has limited applicability as a screening tool for aspiration, silent aspiration, or penetration because of its low sensitivity. This test may be useful for patients who cannot undergo other tests due to cognitive and/or linguistic dysfunction.

Dysphagia Rehabilitation: Similarities and Differences in Three Areas of the World

Although the objective of dysphagia rehabilitation is the same, population needs, clinical practice patterns, availability of resources, and dysphagia research vary greatly around the world. The purpose of this review is to introduce the reader to the context in which dysphagia rehabilitation is practiced, to describe practice patterns, and to emphasize the dysphagia research being performed in three distinct regions of the world: North America, New Zealand and Australia, and Japan.

Dysphagia Causes Exacerbations in Individuals with Chronic Obstructive Pulmonary Disease

memory in elderly adults. TLE is divided into two categories based on location: mesial temporal lobe epilepsy (MTLE) for activity arising from the hippocampus, parahippocampal gyrus, and amygdala and lateral temporal lobe epilepsy (LTLE) for activity arising from the neocortex on the outer surface of the temporal lobe. Clinical features include simple partial seizures without alteration of consciousness, complex partial seizures with altered consciousness and stereotypical movements such as lip smacking (as with thispatient), and secondarily generalized tonic-clonic seizures. Because of the originating location of the seizure activity, memory impairment is common in TLE; approximately 70% of individuals with TLE have memory dysfunction. Not surprisingly, the type of memory impairment is often location specific, with verbal deficits more common with dominant hemisphere involvement (as seen in this individual) and visuospatial deficits more common with nondominant involvement. Numerous studies have reported progressive cognitive decline in individuals with chronic, uncontrolled TLE—a decline associated notonly with the frequency, but also with the severity of seizures. The underlying etiology of TLE remains elusive. One theory suggests that MTLE is due, in large part, to mesial temporal sclerosis—although this feature is not necessary for the development of MTLE. Other theories claim a trigger—such as febrile seizures or infection—as a precipitating event in the subsequent development of TLE. Differential diagnoses include limbic encephalitis, dementia, transient ischemic attack, transient global amnesia, delirium, epileptic transient amnesia, malignancy, and central nervous system infection.

Dysphagia associated with unilateral vocal cord immobility after cardiovascular surgery.

Objective: Dysphagia associated with unilateral vocal cord immobility (UVCI) has received much less attention than did voice and phonation. The aim of this descriptive study was to evaluate the outcome of dysphagia associated with UVCI. Design: Between June 2006 and September 2009, 69 hospitalized patients who underwent cardiovascular surgery were referred for dysphagia. Video endoscopic evaluation of swallowing was used for the detection of swallowing difficulties. Severity of dysphagia was assessed using the Dysphagia Severity Scale. Results: Among the 69 patients, 31 UVCI patients who underwent video endoscopic evaluation of swallowing at least twice were used for analysis. All patients had severe to mild dysphagia at the first evaluation. Nineteen patients recovered from the UVCI at a mean follow-up of 125 days, whereas 12 had persistent UVCI at a mean follow-up of 216 days. Dysphagia Severity Scale at the first evaluation was not significantly different in both groups. At the last follow-up, the Dysphagia Severity Scale improved considerably without a significant difference in the magnitude of improvement in both groups. In the recovered and persistent UVCI groups, 16 and 7 patients, respectively, resumed their regular diets. Conclusions: Dysphagia associated with UVCI after surgery recovers, irrespective of the functional results of the UVCI.

Efficacy of Botulinum Toxin A Treatment for Pes Varus during Gait.

BACKGROUND The efficacy of botulinum toxin A (BoNTA) injection on spasticity is usually measured using Modified Ashworth Scale (MAS), but this only evaluates muscle tone at rest and has poor reliability. There are no reports that quantitatively evaluate pes varus during walking after botulinum treatment. The purpose of this study was to evaluate the efficacy of BoNTA injection on pes varus during gait using 3-dimensional motion analysis. METHODS Twenty-four hemiplegic patients with spastic pes varus deformity during gait received BoNTA injection into lower limb muscles. MAS score, comfortable overground gait velocity, and pes varus angle during treadmill walking were evaluated before, 2, 6, and 12 weeks after the injection. Five healthy subjects were also recruited to develop the pes varus/valgus angle as a normal reference. RESULTS The median MAS scores were significantly lower at 2 and 6 weeks after the injection. The maximum pes varus angle during the swing phase was significantly lower at 2, 6, and 12 weeks after the injection. It was significantly lower at 6 weeks after the injection during stance phase. The comfortable overground gait velocity was also improved after the injection. However, 2 patients experienced pain during gait and their pes varus angle increased during the follow-up period. CONCLUSIONS BoNTA injection improved pes varus angle during gait. Evaluating motion in addition to spasticity at rest is recommended because improvements in limb function do not always parallel improvements in spasticity at rest.

Changes in Pyriform Sinus Morphology in the Head Rotated Position as Assessed by 320-Row Area Detector CT

In patients with unilateral pharyngeal paresis and dysphagia, the head is rotated to the paretic side to prevent food flow to the rotated side during swallowing. Only a few studies to date have reported on pyriform sinus morphology upon head rotation. The purpose of this study was to measure the volume, depth, and cross-sectional area of the pyriform sinus during head rotation using 320-row area detector computed tomography. We imaged the neck during head rotation at 0° and at 30°, 45°, and 60° to the left or right in nine healthy young adults and determined the volume, depth, and cross-sectional area of the pyriform sinus in each position. On the rotated side, volume and cross-sectional area were significantly decreased at 60°. In contrast, volume, cross-sectional area, and depth were all significantly increased on the opposite side at 60°. These results suggest that head rotation at 60° significantly increases the volume, cross-sectional area, and depth of the opposite side, and significantly decreases the volume and depth of the rotated side of the pyriform sinus.

Quantitative assessment of retropulsion of the hip, excessive hip external rotation, and excessive lateral shift of the trunk over the unaffected side in hemiplegia using three-dimensional treadmill gait analysis

Background: Gait assessment is important to determine the most effective strategy to regain gait function during stroke rehabilitation. To understand the mechanisms that cause abnormal gait patterns, it is useful to objectively identify and quantify the abnormal gait patterns. Objective assessment also helps evaluate the efficacy of treatments and can be used to provide suggestions for treatment. Objective: To evaluate the validity of quantitative indices for retropulsion of the hip, excessive hip external rotation, and excessive lateral shift of the trunk over the unaffected side in hemiplegic patients. Methods: Forty-six healthy control subjects and 112 hemiplegic patients participated. From the 112 patients, 50 patients were selected into each abnormal gait pattern with some overlap. Participants were instructed to walk on a treadmill and were recorded using a three-dimensional motion analysis system. An index to quantify each of the three abnormal gait patterns was calculated from the three-dimensional coordinate data. The index values of patients were compared with those of healthy subjects and with the results of observational gait assessment by three physical therapists with expertise in gait analysis. Results: Strong correlation was observed between the index value and the median observational rating for all three abnormal gait patterns (−0.56 to −0.74). Most of the patients with an abnormal gait pattern had a higher index value than the healthy subjects. Conclusions: The proposed indices are useful for clinical gait analysis. Our results encourage a more detailed analysis of hemiplegic gait using a motion analysis system.