Modeling and measurement of flow effects on tracheal sounds.

The analysis of breathing sounds measured over the extrathoracic trachea offers a noninvasive technique to monitor obstructions of the respiratory tract. Essential to development of this technique is a quantitative understanding of how such tracheal sounds are related to the underlying tract anatomy, airflow, and disease-induced obstructions. In this study, the first dynamic acoustic model of the respiratory tract was developed that takes into consideration such factors as turbulent sound sources and varying glottal aperture. Model predictions were compared to tracheal sounds measured on four healthy subjects at target flow rates of 0.5, 1.0, 1.5, and 2.0 L/s, and also during nontargeted breathing. Both the simulation and measurement spectra depicted increasing sound power with increasing flow, with smaller incremental increases at the higher flow rates. A sound power increase of approximately 30 dB between a flow rate of 0.5 and 2.0 L/s was observed in both the simulated and measured spectra. Variations of as much as 15 dB over the 300-600 Hz frequency band were noted in the sound power produced during targeted and nontargeted breathing maneuvers at the same flow rates. We propose that this variability was in part due to changes in glottal aperture area, which is known to vary during normal respiration and has been observed as a method of flow control. Model simulations incorporating a turbulent source at the glottis with respiratory cycle variations in glottal aperture from 0.64 cm2 to 1.4 cm2 explained approximately 10 dB of the measured variation. This study provides the first links between spatially distributed sound sources due to turbulent flow in the respiratory tract and noninvasive tracheal sounds measurements.

Screening practices for gestational diabetes mellitus in UK obstetric units.

AIM: To identify current screening practices for gestational diabetes mellitus (GDM) in all maternity units. METHODS: A questionnaire was sent to the senior obstetrician of all obstetric units known to the UK Royal College of Obstetricians and Gynaecologists. RESULTS: A response rate of 84% was achieved. 89% of units reported that they screened for GDM with a wide variation in the screening methods used, both between and within units. The most commonly employed procedure (81% of units) was screening based on the presence of maternal risk factors. The 75 g oral glucose tolerance test (OGTT) was the commonest diagnostic test (79% of units). Sixty-six per cent of units operate a combined diabetic antenatal clinic and 58% of units have written guidelines for screening. Seventy-six per cent of units would welcome national guidelines. CONCLUSION: The majority of obstetric units in the UK screen for GDM but with little consensus on the appropriate screening methods. National guidelines would probably be welcomed.

Selecting candidates for a lower limb stimulator implant programme: a patient-centred method.

OBJECTIVE: To develop an effective selection procedure for lower limb functional neurostimulation (LLFNS) for standing in paraplegia. DESIGN: The selection procedure and exclusion criteria were based on the previous experience for two clinical centres with experience of LLFNS. SETTING: Two Regional Spinal Injuries units in southern England. SUBJECTS: 254 fully rehabilitated paraplegics living in the community. INTERVENTION: Patients were invited to participate in the programme, and if suitable to subject themselves to a rigorous staged selection procedure from which they could withdraw at any time. OUTCOME MEASURE: Functionally successful home standing using closed-loop surface electrical stimulation. RESULTS: 57/254 patients were suitable on paper and were accessible. 19 of these (CI = 10-28) were interested in the project and attended one of the spinal centres for details. Twelve (CI = 5-19) of these fulfilled the selection criteria and started on the training programme; and 10 of them completed the muscle training programme successfully. Seven patients (CI = 2-12) achieved closed-loop standing in the laboratory and four patients (CI = 1-8) did so at home.

Assisting older adults with severe disabilities in expressing leisure preferences: a protocol for determining choice-making skills.

We evaluated a protocol involving two types of choice presentations for assessing leisure choice-making skills of seven older adults with severe disabilities. Initially when presented with pairs of objects representing choices, choice making was validated through demonstration of an object preference. A more complex choice-presentation format was then employed, involving pictures to represent choices. If the preference identified with objects was not demonstrated using pictures, a replication of the object format occurred to ensure changes in choice making using pictures was not due to a preference change. Five participants demonstrated choice-making skills using objects and two demonstrated choices using pictures. These results reflect the importance of assessing choice-making skills prior to presenting choice opportunities. Suggestions for future research focus on expanding the assessment protocol to include a wider array of choice-making skills and training staff to provide choices in a format commensurate with an individual's skill level.

Lumbar root stimulation for restoring leg function: results in paraplegia.

We have implanted an intradural array of 12 tripolar electrodes on the anterior roots L2-S2, left and right, at cauda equina level, in a 33-year-old woman with a complete T9 cord lesion of 3 years' duration. They are driven by an implanted multiplexed stimulator system using radio frequency (RF) power and control signals. All channels generate movements, in patterns that might be predicted from the known anatomy of the cauda equina. In particular, stimulation of L2 and L3 gives hip adduction; L3, L4, and L5 gives quadriceps femoris movements; L5, S1, and S2 gives hamstrings movement; and S1 and S2 give plantar flexion. Stimulation of L5 gives mixed movements at the ankle. Surprisingly, stimulation of the L2 roots has not given strong hip flexion. Responses have been stable. Some thresholds have varied, probably as a result of tissue encapsulation. The moment generated within each degree of freedom of the legs has been measured for each root, using a specially designed multimoment measurement apparatus. For several roots, a movement of lower threshold may be accompanied by a second movement of higher electrical threshold, suggesting that different muscles may have fiber populations that differ in their diameter or their location in the root. The use of stimulus forms that enable selective anodal block may, in the future, enable separation of two distinct movements from a single motor root.

Akathisia in adults with mental retardation: development of the Akathisia Ratings of Movement Scale (ARMS).

We developed an akathisia rating scale for use with persons who have mental retardation and screened for the occurrence of akathisia in three samples: 66 adults receiving maintenance neuroleptic treatment, 20 adults not receiving neuroleptics, and 8 adults undergoing neuroleptic dose reduction. The scale had an acceptable level of interrater reliability and validly measured group differences related to neuroleptic treatment status. Using an empirically derived cut-off-score, we estimated the prevalence rate for akathisia to be 5% in neuroleptic-free subjects, 17% in neuroleptic-maintenance subjects, and 25% in neuroleptic-reduction subjects. Akathisia, dyskinesia, and stereotypy manifested as qualitatively different movement topograhies. The occurrence of dyskinesia stereotyped movement disorder was associated significantly with an increased occurrence of akathisia.

Dyskinetic movement disorder among adults with mental retardation: phenomenology and co-occurrence with stereotypy.

We screened for the occurrence of dyskinetic and stereotypic movement disorders using item-independent screening protocols to determine whether these forms of movement disorder can be distinguished among adults with mental retardation. Stereotypies and dyskinesias were reliably distinguished in terms of topography. Tardive dyskinesia occurred in 18.2% of a cohort of individuals receiving chronic neuroleptic treatment. Stereotypic movement disorder was associated with increased dyskinesia scores and increased prevalence of tardive dyskinesia. Increased dyskinesia scores were also found for subjects exhibiting stereotypy who had been free of neuroleptic treatment for 3 years. Results indicate that dyskinesia and stereotypy are discriminable movement disorders and provide preliminary support for the hypothesis that they may be related by common mechanisms.

An economic evaluation of daycare in the management of hypertension in pregnancy.

OBJECTIVE: To evaluate the efficiency of daycare in the management of hypertension in pregnancy compared with inpatient management with prior domiciliary visits. DESIGN: Comparative study. SETTING: Two maternity teaching hospitals, Glasgow Royal Maternity Hospital which has an established daycare unit and Aberdeen Maternity Hospital with no daycare unit. MAIN OUTCOME MEASURES: Pregnancy outcomes in terms of maternal hypertensive complications, gestation at delivery, mode of delivery, birthweight, Apgar scores, admission rates and length of admission to special care baby unit. RESULTS: There was no significant difference in any of the measured pregnancy outcomes between the two hospitals. The average cost of treating a women with mild hypertension was 154.91 pounds in Glasgow and 136.59 pounds in Aberdeen. The average cost of treating women with a single episode of hypertension and women with a past history of hypertension was 88.65 pounds and 214.12 pounds in Glasgow and 31.18 pounds and 28.28 pounds in Aberdeen, respectively. If these two groups are excluded, the average cost of treating women with mild hypertension was 172.32 pounds in Glasgow and 201.13 pounds in Aberdeen. The majority of women were willing to attend daycare five times per week to avoid admission. CONCLUSION: Daycare management of hypertension in pregnancy is more efficient than inpatient care with prior domiciliary visits for most women, but less efficient for women with transient or previous hypertension. It is very acceptable to women. Domiciliary checking of women with hypertension found at outpatient clinics would reduce resource use.

Chromosome 15 abnormalities and the Prader-Willi syndrome: a follow-up report of 40 cases.

High-resolution chromosome analysis and multiple banding techniques were performed on blood samples from 40 patients with Prader-Willi syndrome (PWS) as a follow-up to our recent report in which we found interstitial deletions of 15q in four of five patients with this syndrome. Of the 40 new patients, 19 had interstitial del(15q), one had an apparently balanced 15;15 translocation, and one was mos46,XX/47,XX+idic(15) (pter leads to q11::q11 leads to pter). These data confirm our previous report and demonstrate that half of all patients with the clinical diagnosis of PWS have chromosome abnormalities involving chromosome 15 detectable by high-resolution methods. Although the majority of these involve a specific deletion of bands 15q11-q12, other alterations of chromosome 15 may be present.

The acardiac anomaly.

Karyotype analysis of a premature human acardiac twin disclosed normal chromosomes. A review of previous cytogenetic, placental and animal studies suggests that chromosomal errors are not the cause of the acardiac anomaly. Rather, they point to the placental vascular anastomoses as the principal pathogenetic event.