Hajime Ogata

Assessment of autonomic function in traumatic quadriplegic and paraplegic patients by spectral analysis of heart rate variability

We analyzed by means of autoregressive spectral analysis the spontaneous beat-to-beat heart rate variability (HRV) of quadriplegic and paraplegic male subjects at rest in the supine position. In agreement with our previous study, in nine of 15 quadriplegic patients only the high-frequency (HF: center frequency = respiratory frequency) component (a marker of vagal modulation of heart rate) was observed. In contrast, in six of the quadriplegic patients both the HF component and the low-frequency (LF: center frequency at approx. 0.1 Hz, 0.03-0.15 Hz in this study) component (a marker of sympathetic and vagal modulation of heart rate) were observed. However, in six quadriplegic patients who presented the LF component, (i) the center frequency of the LF component was lower than that in 10 healthy, sedentary, age-matched males (control I) (P < 0.01), (ii) the power of the HF component was smaller than that in the control-I group (P < 0.01) and (iii) the LF/HF power ratio (an index of sympathovagal balance) was larger than that in the control-I group (P < 0.05). On the other hand, in nine paraplegic patients with an intact 1st-4th thoracic spinal cord, from which the cardiac sympathetic nerves originate, the total power, the power of the LF component and that of the HF component were smaller than those in nine healthy, sedentary, age-matched males (control II) (P < 0.05, P < 0.01 and P < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Total surface bearing below-knee prosthesis: Advantages disadvantages and clinical implications

OBJECTIVE To investigate the total surface bearing (TSB) prosthesis for below-knee amputee patients and to determine its clinical indications. DESIGN Case series. SETTING University hospital and the Welfare Center for the Disabled. PATIENTS Thirty-two subjects who could walk with the TSB prosthesis and had already used the patellar-tendon bearing (or Kondylen-Bettung Münster) socket. MAIN OUTCOME MEASURE Subjective assessment of the TSB socket, consisting of an overall rating and ratings of 13 individual items, was performed, and results were analyzed with Fishers exact test. RESULTS Seventy-five percent of the subjects were satisfied overall with the TSB socket. Of the 13 items, comfort, ease to swing, pain, piston movement, tightness, skin irritation, appearance, and durability were regarded as good by more than 75% of the patients. Donning, perspiration, odor, and staining were regarded as poor by more than 20%. Items that were significantly related with overall satisfaction with the TSB socket were comfort, ease to swing, and piston movement, while donning was significantly related to dissatisfaction. CONCLUSION The TSB socket is suitable for and preferred by many amputee subjects, but some problems remain to be solved.

Test-retest and inter-method reliability of the self-rating Barthel Index

Objective: To develop a self-rating Barthel Index questionnaire (SB) for assessing stroke patients living at home, the test-retest reliability of SB versions 1 and 2 and the inter-method reliability of SB version 3 were examined. Design: Case series. Setting: Clinics of the Department of Rehabilitation Medicine at the University Hospital and two affiliated hospitals. Patients: Thirty-one, 140 and 65 chronic stroke patients living at home, being seen for regular follow-up, and having no severe aphasia for SB versions 1, 2 and 3, respectively. Main outcome measure: Kappa coefficients of items in SB versions 1 and 2 for test-retest reliability; intra-class correlation coefficients of the self-care index, mobility index and total score, kappa coefficients of items and Friedmans two-way ANOVAs of ranking in SB version 3 among the self-ratings, family ratings and occupational therapist (OT) ratings; a regression analysis of age, gender, duration, time for filling in the SB, OT ratings, Mini-Mental State score and aphasia. Results: Kappa coefficients in SB version 2 were higher than those in version 1. Intra-class correlation coefficients in SB version 3 among the three ratings were good, and kappa coefficients in each item were also good or excellent. By Friedmans two-way ANOVA, all the items except walking up/down stairs had no significant difference in ranking. Regression analysis revealed that OT ratings and time for filling in the SB affected the absolute difference of scores between the self-ratings and OT ratings. Conclusion: SB version 3 is sufficiently reliable for practical use.

Gender-Related Differences in Scores of the Barthel Index and Frenchay Activities Index in Randomly Sampled Elderly Persons Living at Home in Japan

The purpose of this study was to examine for gender-related differences in activities of daily living (ADL) and lifestyle of elderly persons living at home, and to support our hypothesis that the gender-related difference in lifestyle of stroke patients derives from their lifestyle prior to the stroke. Participants were randomly sampled elderly persons living at home. Questionnaire sheets including subject profile, Self-Rating Barthel Index (disability index), and Self-Rating Frenchay Activities Index (activity index) were mailed and collected, and the data were analyzed with the t-test and General Linear Model (factorial model with interaction). A total of 752 subjects were recruited, and their average age was 67.1 years. No significant gender-related differences were evident in the disability index including self-care and mobility domains (t-test, P > 0.05). In contrast gender-related differences in the activity index were significant (t-test, P < 0.05) for three factors; gender, age group, and living conditions, and in a covariate disability index (GLM, P < 0.05). Because randomly selected elderly persons in this study exhibited a prominent gender-related difference in lifestyle, we believe the lifestyle difference in stroke patients that we have previously described derives primarily from their premorbid attitude to daily life.

Assessment of autonomic function in myotonic dystrophy by spectral analysis of heart-rate variability

We analyzed by means of autoregressive spectral analysis the spontaneous beat-to-beat heart-rate variability (HRV) of 10 myotonic dystrophy (MD) patients (4 men and 6 women, aged 37-53 years) and 10 age- and sex-matched healthy, sedentary humans (control) at rest in the supine position. All MD patients had no cardiac conduction disturbances (i.e., atrioventricular or intraventricular conduction defects) on 12-lead electrocardiogram and were able to walk and perform daily activities. In the MD group, the total power, the power of the low-frequency component (a marker of sympathetic and vagal modulation of heart rate) and that of the high-frequency component (a marker of vagal modulation of heart rate) were smaller than those in the control group (P < 0.01, P < 0.05 and P < 0.05, respectively). The results of this study suggest that the cardiovascular autonomic nervous system contributing to the HRV may be disturbed even in the MD patients who can walk and perform daily activities. Therefore, one must give careful consideration to the cardiovascular autonomic dysfunction, as well as the cardiac conduction disturbance in the MD patients.

Static Exercise-Induced Increase in Blood Pressure in Individuals With Cervical Spinal Cord Injury

OBJECTIVE To compare the pressor response to static exercise in subjects with cervical spinal cord injury (SCI) at the C6 to C8 level with that in able-bodied control subjects. In these SCI subjects, the descending supraspinal sympathetic neurons and afferent pathways from the contracting muscles to peripheral vessels via the medullary cardiovascular center are damaged. DESIGN Mean arterial blood pressure, heart rate, and plasma concentrations of norepinephrine, epinephrine, renin activity, vasopressin, aldosterone, and human atrial natriuretic peptide were measured during a 2-minute period of sustained contraction of elbow flexor group muscle in 7 SCI subjects and 7 age-matched able-bodied control subjects. RESULTS Static exercise resulted in a significant increase in mean blood pressure (p<.05) in both SCI subjects (pre-exercise. 74.7+/-2.2 mm Hg; static exercise, 81.9+/-4.1 mm Hg) and control subjects (pre-exercise, 101.0+/-4.2 mm Hg; static exercise, 117.0+/-4.9 mm Hg). In SCI subjects, there was no change in heart rate during exercise, whereas in control subjects heart rate increased during exercise (p<.05) (pre-exercise, 8.7+/-3.8 beats/min: static exercise, 76.0+/-3.1 beats/min). There were no significant changes in the hormone levels in the SCI subjects throughout the experiment. CONCLUSION The significant increase in mean blood pressure observed in the present study indicates the presence of peripheral control from muscle receptors and evoked pressor response during static exercise in SCI subjects.

Histochemical and Immunological Analyses of Differentiating Skeletal Muscle Fibers of the Postnatal Rat

Fiber type differentiation as revealed by myosin ATPase activities and the immunological analysis of myosin light chains (MLC) by the Western blotting method were done on the postnatal rat soleus and extensor digitorum longus (EDL) muscles. In the soleus, type 1 (slow-twitch) muscle fibers gradually increase in percentage after postnatal day 10, and, in the EDL, the differentiation of type 2A and 2B (fast-twitch) muscle fibers is also pronounced between postnatal days 10 and 15. The present immunological analysis of MLC indicates that the antigenicity of Lc1S becomes more intense with a rapid decrease in antigenicity of Lc2F from postnatal day 7 in the soleus, while the antigenicity of Lc1F becomes noticeable during the same period in the EDL. These results suggest that the differentiation of slow-twitch fibers is mainly due to that of Lc1S in the soleus and the differentiation of fast-twitch fibers is mainly due to that of Lc1F in the EDL.

Short-term attenuation of natural killer cell cytotoxic activity in wheelchair marathoners with paraplegia

OBJECTIVE To investigate homeostasis of the immune system in athletes with spinal cord injuries during and after racing a wheelchair marathon. DESIGN The study examined changes in the number and function of natural killer (NK) cells in nine male wheelchair marathon athletes (spinal cord injuries between T5 and T12) who completed the 15th Oita International Wheelchair Marathon Race. Blood samples were obtained the day before, immediately after, and 1 day after the race. Blood samples were also obtained from seven age-matched control subjects with spinal cord injuries but who did not exercise regularly. RESULTS The number of peripheral leukocytes increased (p < .01) immediately after the race. In contrast, the number of peripheral NK cells and NK cell cytotoxic activity significantly decreased from 310+/-130/microL to 133 +/-61/microL and from 42.6%+/-3.0% to 38.2%+/-3.2%, respectively (mean+/-SD), immediately after the race. Plasma cortisol levels were increased after the race. However, all parameters returned to control levels within 24 hours. Measurements in control subjects did not change throughout the experiment. CONCLUSION These findings suggest that racing a marathon suppressed peripheral NK cell number as well as NK cell cytotoxic activity in wheelchair athletes and that this was probably mediated by increased postrace cortisol levels. Wheelchair marathon athletes are advised to take extra precaution to avoid infection within 24 hours after racing because of the transient suppression of NK cell cytotoxic activity during this period.

Properties of the flexible pressure sensor under laboratory conditions simulating the internal environment of the total surface bearing socket.

The purpose of this study was to investigate the properties of the flexible pressure sensor under laboratory conditions simulating the internal environment of the total surface bearing (TSB) socket to determine optimal conditions for measuring normal stresses on the stump. The equipment used in the study was the Pressure Distribution Sensor System for Sockets. In a climatic chamber maintained at 37d`C and 70% humidity the sensor sheet was mounted on a measuring apparatus loaded with three 10 kg weights, and output from the sensor was records after loading was adopted as the measured output. Output was greater when weight was decreased than when weight was increased because of hysteresis (paired t-test, p<0.05). The sensor had temperature sensitivity but differences in output were not statistically significant (paired t-test, 0.10>p>0.05). There were no significant differences in output among five sensor sheets or among five sections of four sensor sheets (two-way ANOVA, p>0.05), but repeated loading on the same section of the sensor sheet increased output (two-way ANOVA, p<0.05). Reproducibility and sensitivity distribution of the sensor are considered satisfatory under laboratory conditions, but measurements of rapid and repetitive movements may not be accurate and comparing subtle changes in output from a single sensor is not suitable. The reliability of the sensor in a clinical setting for measuring normal stresses on the stump with the TSB socket should be examined.

Orthotic management of haemophilic arthropathy of the ankle joint

Twenty haemophiliacs (34 ankles) who were prescribed ankle-foot orthoses (AFOs) or foot orthoses (FOs) were evaluated to confirm whether an orthosis improves the haemophilic arthropathy of the ankle joint. The guideline for the orthosis was the following: shoe modification for enquinus deformity, pain or occasional haemorrhages; elastic ankle supporter with a calcaneal silicone pad for occasional haemorrhages; flexible plastic AFO for frequent haemorrhages and AFO with double uprights for frequent haemorrhages in conjunction with the ankle joint deformity. One year after prescribing the orthosis, the frequency of bleeding in the ankle joint with an ankle supporter was reduced, and the range of motions and X-ray findings of the ankle joint had not deteriorated. Therefore, it was concluded that orthotic management for haemophilic arthropathy in addition to prophylactic therapy might be effective.