Effortful swallow enhances vertical hyolaryngeal movement and prolongs duration after maximal excursion.

Effortful swallowing (EFS) is a common compensatory swallowing manoeuver for dysphagia patients. We investigated the influence of EFS on temporal and spatial characteristics of the movements of the hyoid bone, larynx and epiglottis in healthy subjects. A total of 41 volunteers swallowed 10 mL of diluted barium solution using two swallowing strategies: usual and effortful swallowing (USS and EFS). The motions of the hyoid bone, larynx and epiglottis were tracked using frame-by-frame kinematic motion analysis of videofluoroscopic images. Maximal velocities and maximal displacements of hyoid and larynx, the maximal angle of the epiglottic tilt, and the durations of hyoid excursion, laryngeal elevation and epiglottic tilt were measured. Compared to USS, EFS was associated with significantly greater vertical displacement of the hyoid (P < 0.001), vertical and horizontal displacement of the larynx (P = 0.003, P = 0.019), and maximal angle of the epiglottic tilt (P = 0.001). In addition, the durations of the vertical and horizontal excursions of the hyoid, vertical excursion of the larynx and the epiglottic tilt were greater in EFS, compared with USS. Effortful swallowing was also associated with significantly greater maximum velocities of the hyoid and larynx during swallowing. In conclusion, the EFS manoeuver facilitates vertical speed and distance of hyolaryngeal excursion and epiglottic tilt and extends the duration of excursion and the epiglottic tilt, especially after reaching maximal excursion in healthy subjects. These results confirm the temporal and kinematic benefits of airway protection induced by the EFS manoeuver.

Comparison between swallowing-related and limb muscle involvement in dermatomyositis patients.

OBJECTIVE: To determine the relationship between the movement of the hyolaryngeal complex and the motor power of limb muscles and the differences in the hyolaryngeal movement according to the creatine kinase (CK) levels in dermatomyositis patients. METHOD: We retrospectively selected 13 patients who had undergone a videofluoroscopic swallowing study (VFSS) for swallowing difficulty from patients diagnosed with dermatomyositis. The maximal anterior and superior displacements of the hyoid and larynx and the cricopharyngeal opening were acquired by frame-by-frame analysis using the VFSS. We investigated the motor power of the bilateral shoulder abductor, elbow flexor, hip flexor, and knee extensor muscles to determine the limb muscle involvement and used the American Speech-Language-Hearing Association (ASHA) National Outcomes Measurement System (NOMS) swallowing level (ASHA level) to assess dysphagia severity. Spearman's correlation test was used to identify the relationship between the kinematic data of the laryngeal structures, ASHA levels, and the total motor scores in dermatomyositis patients. RESULTS: There was no significant correlation between the kinematic data of the laryngeal structures, ASHA levels, and total motor scores. Only the anterior movements of the hyoid and larynx had a significant relationship to the upper oesophageal sphincter opening. CONCLUSION: Dysphagia evaluation should be considered separately in dermatomyositis patients irrespective of limb involvement or dysphagia severity because the swallowing-related muscle involvement had no relationship to the limb muscle involvement or the severity of dysphagia in dermatomyositis. It is hoped that our results can be used to evaluate the therapeutic effects of dysphagia management in dermatomyositis patients.

Kinematic analysis of hyolaryngeal complex movement in patients with dysphagia development after pneumonectomy.

PURPOSE: Aim of the study was to investigate the swallowing kinematics of patients with dysphagia which developed after pneumonectomy. METHODS: We investigated the swallowing kinematics of patients with dysphagia development after pneumonectomy and compared them with age- and gender-matched normal controls. The following swallowing parameters were compared: (1) maximum anterior and superior displacement (mm) of the hyoid bone; (2) maximum anterior and superior displacement (mm) of the larynx; (3) maximum epiglottic rotation angle ( degrees ); and (4) pharyngeal delay time (PDT) (sec) using videofluoroscopy. RESULTS: Significant differences were found in the maximum superior displacement of the hyoid bone ( P = 0.028) and larynx ( P = 0.001). Pharyngeal delay time showed a significant difference between the two groups ( P = 0.001). When we dichotomized patients to vocal cord palsy and non-palsy subgroups, no significant difference was found in all parameters. CONCLUSION: Our results indicate that dysphagia development after pneumonectomy is characterized by reduced hyolaryngeal elevation during swallowing and delay of the pharyngeal swallowing reflex. Further study must be done to reveal the exact mechanism of this phenomenon.

Sensory and instrumental analysis for slipperiness and compliance of food during swallowing.

In spite of its importance, there have been few attempts to evaluate the sensory attributes of the food bolus during swallowing. In the current study, the slipperiness, the degree of slide for the food bolus through the mucosal surface of the oro-pharynx, and the compliance, how easily the shape of a food bolus can be transformed for automatic and comfortable swallowing, were derived among several sensory attributes related to the swallowing. Therefore, the study aims were twofold: (1) to develop the methods of sensory and instrumental analyses for determining the slipperiness and compliance of the food bolus during swallowing and (2) to examine the appropriateness of the newly designed devices by correlating the data between the sensory and instrumental analyses. Six commercial food products were evaluated by 10 trained panelists for each attribute. The devices for assessing each attribute were developed in consideration of the oro-pharyngeal movements. The sensory and instrumental analyses showed high correlation and regression coefficients as well as intensity differences of the 6 samples for each attribute. In conclusion, the slipperiness and the compliance were suitable for acquiring a better understanding of the sensory attributes of the food bolus during swallowing, and the newly developed devices showed a high potential for determining those attributes.

Effect of cold air therapy in relieving spasticity: applied to spinalized rabbits.

STUDY DESIGN: Before-After trial measured prior to cold air therapy, immediately following, after 30 and 60 min. OBJECTIVE: To determine the effect of cold air therapy in relieving spasticity, the optimal intramuscular temperature, and the duration of spasticity relief attained by cold air therapy. SETTING: Clinical research laboratory, Seoul, Korea. SUBJECT: Forty-six spastic paraplegic rabbits with spinal cord injury. METHODS: Spastic paraplegia was induced by transection of spinal cord in 46 rabbits. Cold air was applied to triceps surae muscles for 30 min at three different intramuscular temperatures (25, 30 and 32.5 degrees C). Clinical parameters of spasticity (muscle tone, Babinski's sign, muscle stretch reflex and ankle clonus) and electrophysiologic parameters (F/M ratio and H/M ratio) were measured immediately following, after 30 and 60 min. RESULTS: In the 32.5 degrees C group, relief in spasticity lasted less than 30 min. In the 30 and 25 degrees C groups, the decrease in spasticity lasted for at least 30 min clinically. The spasticity relief was observed only immediately following treatment when measured electrophysiologically. However, six out of 16 cases (37.5%) in the 25 degrees C group showed complete motor conduction block. CONCLUSION: To relieve spasticity with cold air therapy, the intramuscular temperature should be maintained at 30 degrees C. The duration of spasticity relief lasted from between 30-60 min after cold air therapy. We certify that all applicable institutional and governmental regulations concerning the ethical use of animals were followed during the course of this research.

Phenol block of peripheral nerve conduction: Titrating for optimum effect.

OBJECTIVES: To verify the dose-response relationship in phenol nerve block and to determine the concentration and volume of phenol injectate required for effective nerve conduction block. DESIGN: Before-after, experimental study. SETTING: A research institute laboratory. ANIMALS: Seventy-one New Zealand white rabbits. INTERVENTIONS: Group I (n = 48) received tibial nerve block by perineural injection (phenol, n = 40; saline, n = 8), group II (n = 21) by submerging the nerve in phenol solution. The 6 subgroups of group I each received different concentrations (3%, 4%, 5%) and volumes (0.1mL, 0.2mL, 0.3mL). The 2 subgroups of group II received 3% (n = 8) and 5% (n = 13) phenol. MAIN OUTCOME MEASURES: Compound muscle action potential (CMAP) and tension of triceps surae muscles by electric stimulation of the sciatic nerve were measured preintervention and at day 1, and weeks 1, 2, 4, and 8 postblock. Histologic studies were performed on 2 animals from group I. RESULTS: Two rabbits in group I died before results were obtained. In the remaining animals, CMAP amplitude reduced significantly (p <.05) as the volume of 5% phenol solution increased from 0.1mL, 0.2mL, to 0.3mL. A high concentration of phenol produced a more pronounced conduction block; however, no significant (p =.0589) difference existed among the 3 concentrations. Submerged tibial nerve had a greater degree of conduction block than perineurally injected nerve. Depth of the degeneration area in nerve fascicle varied with distance from the injection point. CONCLUSIONS: The nerve block effect of phenol can be titrated by adjusting the concentration and volume of phenol solution if the technique of application and localization of a block site are standardized.

Quantifying swallowing function after stroke: A functional dysphagia scale based on videofluoroscopic studies.

OBJECTIVE: To develop a sensitive, specific scale for quantifying functional dysphagia in stroke patients, using results obtained from videofluoroscopic swallowing studies. DESIGN: Data collected from a serial oral and pharyngeal videofluoroscopic swallowing study. SETTING: A dysphagia clinic in a department of rehabilitation medicine at a tertiary care university hospital. PARTICIPANTS: One hundred three consecutively admitted stroke patients. INTERVENTIONS: Videoflurorscopy to measure a scale of 11 variables: lip closure score, bolus formation, residue in oral cavity, oral transit time, triggering of pharyngeal swallow, laryngeal elevation and epiglottic closure, nasal penetration, residue in valleculae, coating of pharyngeal wall after swallow, and pharyngeal transit time. MAIN OUTCOME MEASURES: Polychotomous linear logistic regression analysis of videofluoroscopic and aspiration results. Scale sensitivity and specificity, and the correlation between the total score of the scale and aspiration grade were analyzed. RESULTS: The scale's sensitivity and specificity for detecting supraglottic penetration and subglottic aspiration were 81%, 70.7%, and 78.1%, 77.9%, respectively. A significant positive correlation was found between the scale's total score and the severity of aspiration (Spearman's r =.58943, p =.00001). CONCLUSION: This functional dysphagia scale, which was based on a videofluoroscopic swallowing study in stroke patients, is a sensitive and specific method for quantifying the severity of dysphagia.

Roles of histidine residues in tobacco acetolactate synthase.

Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of valine, leucine, and isoleucine in plants and microorganisms. ALS is the target of several structurally diverse classes of herbicides, including sulfonylureas, imidazolinones, and triazolopyrimidines. The roles of three well-conserved histidine residues (H351, H392, and H487) in tobacco ALS were determined using site-directed mutagenesis. Both H487F and H487L mutations abolished the enzymatic activity as well as the binding affinity for the cofactor FAD. Nevertheless, the mutation of H487F did not affect the secondary structure of the ALS. The K(m) values of H351M, H351Q, and H351F are approximately 18-, 60-, and fivefold higher than that of the wild-type ALS, respectively. Moreover, the K(c) value of H351Q for FAD is about 137-fold higher than that of wALS. Mutants H351M and H351Q showed very strong resistance to Londax (a sulfonylurea) and Cadre (an imidazolinone), whereas mutant H351F was weakly resistant to them. However, the secondary structures of mutants H351M and H351Q appeared to be different from that of wALS. The mutation of H392M did not have any significant effect on the kinetic parameters nor the resistance to ALS-inhibiting herbicides. These results suggest that the His487 residue is located at the active site of the enzyme and is likely involved in the binding of cofactor FAD in tobacco ALS. Mutational analyses of the His351 residue imply that the active site of the ALS is probably close to its binding site of the herbicides, Londax and Cadre.

Effect of facilitation on side-to-side H reflex amplitude ratio.

Although voluntary facilitation is sometimes necessary to evoke the H reflex, relevant data is lacking on side-to-side amplitude ratios in facilitated condition. To determine the normal limits of H reflex amplitude ratio in facilitation and to assess it's clinical applicability, we performed FCR H reflex study in fifty asymptomatic subjects. The lower limit of the amplitude ratio that encompasses 97.5% of subjects in facilitation was 0.48. These data suggest H reflex amplitude ratio measured in facilitation without averaging is useful for the diagnosis of unilateral radiculopathy.

Optimization of facilitation related to threshold in transcranial magnetic stimulation.

OBJECTIVES: To attain the standardized procedure for optimal facilitation, we analyzed motor-evoked potential (MEP) responses to the degree of voluntary contraction and stimulus intensity. METHODS: Fifteen normal subjects were included. MEPs were elicited at thenar muscles during rest and at gradual voluntary contraction (MVC), using 10, 30, and 50% of MVC. During rest and each contraction, the excitability threshold at rest (RET) and at contraction (CET) were determined. Consecutive stimuli were applied, with the intensity of ratio increments (110-150% of ET). RESULTS: The RET showed a remarkable decrease after contraction. Shortening of latency reached a saturation level at 10% of MVC. Amplitude reached a saturation level at 30% of MVC with 62.7+/-8.5% of the maximum output, which is equal to 140% intensity of CET, and 110% of RET. The MEP amplitudes at rest and at 10% MVC were influenced by their ETs, but those measured above 30% of MVC were not related. CONCLUSIONS: The procedure recommended for optimal facilitation is as follows: to achieve minimal latency of MEPs, a minimal contraction (10% of MVC) with RET intensity is sufficient and for maximal amplitude, a moderate contraction (30% of MVC) with 110% of RET intensity is adequate.

The optimal measurement of across elbow segment in ulnar motor conduction study.

There is room for considerable error in the measurement of across-elbow conduction velocity due to the different possible positions of the elbow and the difficulty in accurately measuring distance. A standardized method should be used for clinical measurement. Many advocate a fully flexed elbow position with the arm abducted at 90 degrees. When the elbow is fully flexed, skin measurement across the bent elbow is difficult with respect to defining the path, which most accurately follows the nerve. However, studies on measurement technique for across-elbow segment have not been performed to date. We have proposed a standardized technique for the measurement of conduction velocity through the elbow segment. We assumed "ideal" across-elbow segmental conduction velocity is the mean of the forearm and arm segmental conduction velocities, and established an optimal deflection point at the elbow, which best reflects the ideal conduction velocity. The optimal deflection point was located medially two thirds distance between the epicondyle and the olecranon in an arm abducted 90 degrees, fully flexed elbow position. Our data suggests that an across-elbow segment velocity lower than 57.8 m/sec, or a difference of more than 7.7 m/sec between the across-elbow and forearm segments is to be considered abnormal. The lower limit values expressed as mean-2 S.D. for absolute across-elbow segmental conduction velocity and relative velocity difference between the across-elbow segment and forearm segments at other possible deflection points of the elbow were also calculated.

Multiple peripheral nerve compressions related to malignantly transformed hereditary multiple exostoses.

Autosomal dominantly transmitted hereditary multiple exostoses is an uncommon disorder consisting of multiple projections of bone capped by cartilage. The lesions are most numerous in the metaphyses of long bones but may appear on flat bones. Sarcomatous transformation occurs in 1-25% of patients. We report a 33-year-old man with sciatica, previously diagnosed as hereditary multiple exostoses, presenting with multiple peripheral nerve compressions. Electrodiagnostic studies showed profound axon-loss multiple neuropathies involving the sciatic, superior gluteal, and inferior gluteal nerves. Magnetic resonance imaging of the left pelvis showed a large mass in the sacral area that was suggestive of a chondrosarcoma. An open intralesional excision biopsy confirmed chondrosarcoma transformed from chondromatosis. Excision of the lesion was effective in eliminating the impingement of nerves and retarding progressive osseous growth. We suggest that malignant transformation be suspected in cases with focal compression neuropathy of patients known to have multiple exostoses. Osteochondroma as a possible cause for compression neuropathy is discussed.

Fetal exposure to an intra-amniotic inflammation and the development of cerebral palsy at the age of three years.

OBJECTIVE: The aim of this study was to determine whether fetal exposure to intra-amniotic inflammation and a systemic fetal inflammatory response (funisitis) are associated with the development of cerebral palsy at the age of 3 years. STUDY DESIGN: This cohort study included 123 preterm singleton newborns (gestational age at birth, /=3 years. The presence of intra-amniotic inflammation was determined by elevated amniotic fluid concentrations of proinflammatory cytokines such as interleukins 6 and 8 and by amniotic fluid white blood cell count. Cytokine concentrations were measured with sensitive and specific immunoassays. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton jelly. Cerebral palsy was diagnosed by neurologic examination at the age of 3 years. RESULTS: Newborns with subsequent development of cerebral palsy had a higher rate of funisitis and were born to mothers with higher median concentrations of interleukins 6 and 8 and higher white blood cell counts in the amniotic fluid compared with newborns without subsequent development of cerebral palsy (funisitis: 75% [9/12] vs 23% [24/105]; interleukin 6: median, 18.9 ng/mL; range, 0. 02-92.5 ng/mL; vs median, 1.0 ng/mL; range, 0.01-115.2 ng/mL; interleukin 8: median, 13.0 ng/mL; range, 0.1-294.5 ng/mL; vs median, 1.2 ng/mL; range, 0.05-285.0 ng/mL; white blood cell count: median, 198 cells/mm(3); range, 0->1000 cells/mm(3); vs median, 3 cells/mm(3); range, 0-19,764 cells/mm(3); P <.01 for each). After adjustment for the gestational age at birth, the presence of funisitis and elevated concentrations of interleukins 6 and 8 in amniotic fluid significantly increased the odds of development of cerebral palsy (funisitis: odds ratio, 5.5; 95% confidence interval, 1.2-24.5; interleukin 6: odds ratio, 6.4; 95% confidence interval, 1. 3-33.0; interleukin 8: odds ratio, 5.9; 95% confidence interval, 1. 1-30.7; P <.05 for each). CONCLUSION: Antenatal exposure to intra-amniotic inflammation and evidence of a systemic fetal inflammatory response (funisitis) are strong and independent risk factors for the subsequent development of cerebral palsy at the age of 3 years.

Quantification of the path of center of pressure (COP) using an F-scan in-shoe transducer.

By tracking the path of the center of pressure (COP) during the stance phase, the balance and pattern of progression can be determined. The path of COP is frequently used in clinical practice, although it is not quantified. In this study, an F-scan pressure sensitive insole system was used to quantify the path of COP. The COP of initial contact and the average during the stance phase corresponded to the center of the heel and to the center of the total plantar surface, respectively. The COP displacement corresponded to 83% of foot contact length and 18% of forefoot contact width. When the longitudinal axis of the insole was plotted as the Y-axis and the transverse axis of the insole as X-axis, the slopes of the COP coordinates during stance phase was 6 degrees inward. Velocities of the COP during each functional rocker action were even and 22-27 cm/s. The changes of quantified COP parameters according to the biomechanical alteration of the foot were confirmed by high-heeled gait.

Acute sensory neuronopathy: identified with electrodiagnosis and magnetic resonance imaging.

We report on a 13-year-old female with idiopathic acute sensory neuronopathy mimicking a sensory form of Guillain-Barré syndrome, which was identified by using electrodiagnosis and spine magnetic resonance imaging. Motor conduction results were normal, but no sensory nerve action potentials were seen in the four limbs. On magnetic resonance imaging of the whole spine, the diffuse gadolinium enhancement of the dorsal roots in the spinal canal was detected, without evidence of intramedullary lesions. The clinical symptoms and electrodiagnostic findings had persisted for more than 18 months of follow-up.

Optimal electrode placement in facial nerve conduction study.

This study was designed to determine the optimal sites for the active electrode in a nerve conduction study of each branch of the facial nerve. Twenty healthy male and female volunteers between 20 and 40 years old were investigated. Our criteria for the optimal site of the active electrode were initial negative deflection and maximal amplitude of the response and the most synchronized response. Optimal sites were found to be as follows: 1. Frontalis (temporal branch): a point midway between the hairline and the eyebrow along a line passing vertically through the pupil. 2. Orbicularis oculi (zygomatic branch): the medial quarter between the medial and lateral canthus. 3. Nasalis (buccal branch): muscle belly. 4. Triangularis (mandibular branch): 15 mm lateral and 25 mm below the corner of the mouth. 5. Orbicularis oris (zygomatic, mandibular and buccal branches): 2 mm below the lower lip midway between the midline and the corner of the mouth.

Chronic gastrointestinal problems and bowel dysfunction in patients with spinal cord injury.

Amongst complications arising from spinal cord injury (SCI), chronic gastrointestinal (G-I) problems and bowel dysfunction have not received as much research attention as many other medical and rehabilitation problems, even although their incidence is not negligible. We therefore investigated chronic G-I problems and bowel dysfunction in SCI patients where the degree of these was such that activities of daily living (ADL) were significantly affected and/or long-term medical management was required. Detailed semi-structured individual interviews were conducted with 72 traumatic SCI patients. The history of SCI was longer than 6 months, bowel habits had settled, and neurological recovery was completed. The incidence of chronic G-I problems was very high (62.5%), most were associated with defecation difficulties such as severe constipation, difficult with evacuation, pain associated with defecation, or urgency with incontinence. These problems had an extensive impact on ADL, and in particular, restricted diet (80%), restricted outdoor ambulation (64%) and caused unhappiness with bowel care (62%). Bowel care was performed once per 2.85 +/- 1.96 days and occupied an average of 42.1 +/- 28.7 min. To improve bowel habits, 43% of the patients took oral medication, and 36.1% controlled their diet. The usual methods of bowel care were anal massage (34.7%), unaided self-defecation with or without oral medication and abdominal massage (29.2%), finger enema (18.1%), rectal suppository (15.2%) and in two patients a colostomy tube had been inserted because of rectal cancer and traumatic colorectal injury. These chronic G-I symptoms were vague and very subjective, but significant enough to affect the quality of life. Bowel dysfunction was not related to age, duration of, or the neurological level of injury, ASIA score of ADL level, and bowel habits had generally settled within 6 months of SCI. With regard to frequency, time, and method of defection, bowel care habits varied considerably amongst individuals, and in relation to the extent to which practical results matched the level of expectation generated by physicians' recommended care program. Individual satisfaction was also very subjective. We therefore suggest that during the early stage of rehabilitation, an appropriate bowel program should be properly designed and adequate training provided.

A study on new diagnostic criteria of H reflex.

H reflex is known as a useful electrodiagnostic test in the diagnosis of S1 radiculopathy. But, only the latency difference has been the useful parameter by previously published conventional method. Under the assumption that the constant appearance of initial negative biphasic H wave is critical to study H reflex using parameters such as amplitude, area and shape, we developed a new method using parameters such as amplitude, area and shape. To validate our assumption and to compare the diagnostic values between the conventional method and the new one, we studies H reflex in 330 subjects. One hundred sixty-two subjects were studied by conventional method and 168 subjects were studied by our new method. There was no definite difference in diagnostic values between two methods by latency criteria. However, new method was more specific for S1 radiculopathy than conventional method by amplitude and area criteria. Parameters such as amplitude, area and shape can be used significantly only in the new method. Therefore, we suggest new diagnostic criteria of abnormal response as follows: (1) H latency difference over 1.0 msec and H/H amplitude ratio less than 0.5 or (2) H latency over 30 msec or (3) unilateral absent evoked H response.

Changes in somatosensory-evoked potentials in limb lengthening. An experimental study on rabbits' tibiae.

To assess the influence of the rate and amount of distraction on the electrophysiologic function of the peripheral nerve during limb lengthening, somatosensory-evoked potential (SSEP) studies were performed on the hindlimbs of 96 rabbits. In Group I, the tibiae were lengthened 0.35 mm per day; in Group II, 0.7 mm per day; in Group III, 1.05 mm per day; and in Group IV, 1.4 mm per day. The studies were done preoperatively and then postoperatively, until six weeks in Group I, five weeks in Group II, four weeks in Group III, and three weeks in Group IV. As lengthening proceeded, the P1 (the first major positive peak) latency gradually increased, whereas the amplitude decreased. Significant amplitude changes were observed at six-weeks postsurgery in Group I, three weeks in Group II, two weeks in Group III, and one week in Group IV. Significant changes in P1 latency were observed at four weeks postsurgery in Group II, three weeks in Group III, and two weeks in Group IV. Greater percentage increases in tibial length corresponded to more marked changes in P1 latency and amplitude. The SSEP monitoring may serve as an effective tool for early detection of neurologic dysfunction during limb lengthening.