The 'Pelvic exenteration lexicon': Creating a common language for complex pelvic cancer surgery

AIM

Pelvic exenteration surgery is an umbrella term for a multitude of operative techniques for locally advanced and recurrent pelvic malignancy. Currently, there is heterogeneity in the operative description that limits the interpretation of patient outcome and collaboration between units through standardized data collection. Our study aims to develop a consensus lexicon to describe the operative components of extended and exenteration pelvic surgery.

METHOD

This study adopted a mixed-methods approach using semi-structured interviews, questionnaires, focus groups and validation exercises involving pelvic exenteration experts from centres in the UK. Qualitative data were collected, and descriptive statistics are presented.

RESULTS

We identified eight headings with 32 subheadings that encompass all components of the extent of the potential surgery. The lexicon was validated by 15 UK specialists. A 'high-complexity pelvic exenteration' was defined as encompassing 'conventional pelvic exenteration' with the extension of surgery to remove bony structures or the structures in the pelvic sidewall. Pelvic sidewall structures include major vessels, sciatic nerves and/or bone. Bony structures include the sacrum and/or pubic bones.

CONCLUSION

This pelvic exenteration lexicon will permit classification of the surgical approach used that will improve data synthesis, allow more accurate activity recording for audit and ultimately improved outcomes for patients.

Effect of the SARS-CoV-2 pandemic on mortality related to high-risk emergency and major elective surgery

These data show large reductions in both elective and emergency activity that are concerning for unmeasured morbidity and mortality within the community. The risk of mortality following high-risk EGS and major elective surgery during the first wave of the pandemic did not differ when compared with date-matched patient cohorts from 2019. The prevalence of concomitant SARS-CoV-2 infection in this surgical population is low.

An audit of process and outcome for emergency colectomy in England and Wales

AIM

The aim of this work was to describe process and outcome for patients undergoing emergency colectomy for colitis in England and Wales.

METHOD

The National Emergency Laparotomy Audit (NELA) is a national audit including patients undergoing emergency laparotomy and laparoscopic resectional procedures. Data from adult patients under 65 years of age who underwent emergency subtotal colectomy or panproctocolectomy for colitis between 2013 and 2016 were analysed.

RESULTS

In total 1204 patients were included. Although approximately a third of patients underwent a colectomy within 5 days of admission [37% (440/1204)], 32% (383/1204) were admitted for more than 10 days prior to surgery. Colorectal surgeons were present at operation in 72% (869/1204) of cases and consultant surgeons attended 94% (1137/1204) of procedures. Laparoscopy was attempted in 32% (390/1204) of operations with wide institutional variation in its use (0-100% of cases). The overall 30-day inpatient mortality was 2.9% (35/1204). On multivariable regression analysis, age > 55 years [OR 3.59 (1.05-12.21), P = 0.041], female gender [OR 2.88 (1.27-6.52), P = 0.011] and American Society of Anesthesiologists grade 5 [OR 37.43 (2.72-514.52), P = 0.007] were associated with increased mortality.

CONCLUSION

There is a consultant-driven service that is largely delivered by specialist colorectal surgeons. Laparoscopy rates were high although there was wide variation in use across institutions. Preoperative delays were evident, and further work is necessary to determine the underlying reasons for these.

Delays in referral from primary care are associated with a worse survival in patients with esophagogastric cancer

NICE referral guidelines for suspected cancer were introduced to improve prognosis by reducing referral delays. However, over 20% of patients with esophagogastric cancer experience three or more consultations before referral. In this retrospective cohort study, we hypothesize that such a delay is associated with a worse survival compared with patients referred earlier. By utilizing Clinical Practice Research Datalink, a national primary care linked database, the first presentation, referral date, a number of consultations before referral and stage for esophagogastric cancer patients were determined. The risk of a referral after one or two consultations compared with three or more consultations was calculated for age and the presence of symptom fulfilling the NICE criteria. The risk of death according to the number of consultations before referral was determined, while accounting for stage and surgical management. 1307 patients were included. Patients referred after one (HR 0.80 95% CI 0.68-0.93 p = 0.005) or two consultations (HR 0.81 95% CI 0.67-0.98 p = 0.034) demonstrated significantly improved prognosis compared with those referred later. The risk of death was also lower for patients who underwent a resection, were younger or had an earlier stage at diagnosis. Those presenting with a symptom fulfilling the NICE criteria (OR 0.27 95% CI 0.21-0.35 p < 0.0001) were more likely to be referred earlier. This is the first study to demonstrate an association between a delay in referral and worse prognosis in esophagogastric patients. These findings should prompt further research to reduce primary care delays.

Colorectal cancer patients under the age of 50 experience delays in primary care leading to emergency diagnoses: a population-based study

AIM

The incidence of colorectal cancer in the under 50s is increasing. In this national population-based study we aim to show that missed opportunities for diagnosis in primary care are leading to referral delays and emergency diagnoses in young patients.

METHOD

We compared the interval before diagnosis, presenting symptom(s) and the odds ratio (OR) of an emergency diagnosis for those under the age of 50 with older patients sourced from the cancer registry with linkage to a national database of primary-care records.

RESULTS

The study included 7315 patients, of whom 508 (6.9%) were aged under 50 years, 1168 (16.0%) were aged 50-59, 2294 (31.4%) were aged 60-69 and 3345 (45.7%) were aged 70-79 years. Young patients were more likely to present with abdominal pain and via an emergency, and had the lowest percentage of early stage cancer. They experienced a longer interval between referral and diagnosis (12.5 days) than those aged 60-69, reflecting the higher proportion of referrals via the nonurgent pathway (33.3%). The OR of an emergency diagnosis did not differ with age if a red-flag symptom was noted at presentation, but increased significantly for young patients if the symptom was nonspecific.

CONCLUSION

Young patients present to primary care with symptoms outside the national referral guidelines, increasing the likelihood of an emergency diagnosis.

Complications after discharge and delays in adjuvant chemotherapy following colonic resection: a cohort study of linked primary and secondary care data

AIM

By understanding the reasons for delays in adjuvant chemotherapy (AC) after colonic resection, there is the potential to improve patient outcome. The aim of this study is to determine the extent and impact of complications after hospital discharge on delays to AC.

METHOD

The study cohort included patients from Hospital Episode Statistics (HES) who had a colorectal cancer resection; linkage to primary care data was provided by the Clinical Practice Research Datalink (CPRD). Complications during the index hospital stay (from HES) and after discharge (from CPRD) were compared. The risk of late AC treatment (8 weeks or later) following a complication, stoma at the index procedure or emergency admission was described after accounting for age and Charlson score. A Cox hazards model determined the association of these factors with overall survival (OS).

RESULTS

A total of 1266 patients underwent AC following colon cancer resection, of whom 598 (47.2%) received treatment within 8 weeks. Patients receiving late AC had a significantly higher proportion of re-operations (7.0% vs 3.3% P < 0.005) and wound infections (5.5% vs 3.7% P = 0.042), with 96% of the latter only being noted in CPRD. In multivariate analysis, the risk of AC delay significantly increased following a complication (OR 1.53, 95% CI 1.16-2.03, P = 0.003) or a stoma at the index operation. AC delay was associated with worse OS [hazard ratio (HR) 1.44, 95% CI 1.16-1.79, P = 0.001], as was an emergency admission (HR 1.59, 95% CI 1.21-1.98, P < 0.0005). However, the presence of a complication did not independently reduce OS (HR 1.15, 95%CI 0.89-1.48, P = 0.295).

CONCLUSION

The true extent and impact of complications following colonic resection is underestimated when only secondary care data are used.

Risk of desmoid formation after laparoscopic versus open colectomy and ileorectal anastomosis for familial adenomatous polyposis

Background

Laparoscopy is used increasingly in prophylactic surgery for patients with familial adenomatous polyposis (FAP) undergoing colectomy with ileorectal anastomosis (IRA). Little is known about the impact of laparoscopy on subsequent desmoid risk. This study documented the risk of desmoid in patients undergoing laparoscopic and open IRA.

Methods

This was an observational study of patients with FAP and known germline APC mutation, undergoing IRA at a tertiary referral centre between 1996 and 2016. Patients were retrieved from a prospectively maintained polyposis registry. Data included genotype, family history of desmoid, sex, surgical approach at IRA and postoperative complications. The main outcome was development of either a clinically or radiologically significant desmoid.

Results

Some 112 patients (61 female) underwent colectomy and IRA. A laparoscopic approach was used in 69 patients (61·6 per cent). Baseline characteristics did not differ between patients having an open or laparoscopic approach. Median follow‐up was 5·8 (i.q.r. 2·4–11·2) years. Patients who underwent laparoscopic IRA had a reduced risk of desmoid formation (3 of 69 (4 per cent) versus 7 of 43 (16 per cent) in the open group; P = 0·043).

Discussion

Laparoscopic IRA may reduce risk of subsequent desmoid formation in patients with FAP.

Linked hospital and primary care database analysis of the impact of short-term complications on recurrence in laparoscopic inguinal hernia repair

OBJECTIVE

To study the effects of short-term complications on recurrence following laparoscopic inguinal hernia repair using routine data.

BACKGROUND

Linked primary and secondary care databases can evaluate the quality of inguinal hernia surgery by quantifying short- and long-term outcome together.

METHODS

Longitudinal analysis of linked primary care (Clinical Practice Research Datalink) and hospital administrative (Hospital Episodes Statistics) databases quantified 30-day complications (wound infection and bleeding) and surgery for recurrence after primary repair performed between 1st April 1997 and 31st March 2012.

RESULTS

Out of 41,545 primary inguinal hernia repairs, 10.3% (4296/41,545) were laparoscopic. Complications were less frequent following laparoscopic (1.8%, 78/4296) compared with open (3.5%, 1288/37,249) inguinal hernia repair (p < 0.05). Recurrence was more frequent following laparoscopic (3.5%, 84/2541) compared with open (1.2%, 366/31,859) repair (p < 0.05). Time to recurrence was shorter for laparoscopic (26.4 months SD 28.5) compared with open (46.7 months SD 37.6) repair (p < 0.05). Overall, complications were associated with recurrence (3.2%, 44/1366 with complications; 1.7%, 700/40,179 without complications; p < 0.05). Complications did not significantly increase the risk of recurrence in open hernia repair (OR = 1.49; 95% CI 0.97-2.30, p = 0.069). Complications following laparoscopic repair was significantly associated with increased risk of recurrence (OR = 7.86; 95% CI 3.46-17.85, p < 0.05).

CONCLUSIONS

Complications recorded in linked routine data predicted recurrence following laparoscopic inguinal hernia repair. Focus must, therefore, be placed on achieving good short-term outcome, which is likely to translate to better longer term results using the laparoscopic approach.

The psychological impact of symptoms related to esophagogastric cancer resection presenting in primary care: A national linked database study

BACKGROUND

The objective was to evaluate incidence, risk factors and impact of postoperative symptoms following esophagogastric cancer resection in primary care.

METHODS

Patients undergoing esophagogastrectomy for cancer from 1998 to 2010 with linked records in Clinical Practice Research Datalink, Hospital Episodes Statistics and Office of National Statistics databases were studied. The recording of codes for reflux, dysphagia, dyspepsia, nausea, vomiting, dumping, diarrhea, steatorrhea, appetite loss, weight loss, pain and fatigue were identified up to 12 months postoperatively. Psychiatric morbidity was also examined and its risk evaluated by logistic regression analysis.

RESULTS

Overall, 58.6% (1029/1755) of patients were alive 2 years after surgery. Of these, 41.1% had recorded postoperative symptoms. Reflux, dysphagia, dyspepsia and pain were more frequent following esophagectomy compared with gastrectomy (p < 0.05). Complications (OR = 1.40 95%CI 1.00-1.95) and surgical procedure predicted postoperative symptoms (p < 0.05). When compared with partial gastrectomy, esophagectomy (OR = 2.03 95%CI 1.26-3.27), total gastrectomy (OR = 2.44 95%CI 1.57-3.79) and esophagogastrectomy (OR = 2.66 95%CI 1.85-2.86) were associated with postoperative symptoms (p < 0.05). The majority of patients with postoperative psychiatric morbidity had depression or anxiety (98%). Predictors of postoperative depression/anxiety included younger age (OR = 0.97 95%CI 0.96-0.99), complications (OR = 2.40 95%CI 1.51-3.83), psychiatric history (OR = 6.73 95%CI 4.25-10.64) and postoperative symptoms (OR = 1.78 95%CI 1.17-2.71).

CONCLUSIONS

Over 40% of patients had symptoms related to esophagogastric cancer resection recorded in primary care, and were associated with an increase in postoperative depression and anxiety.

The impact of shortened postgraduate surgical training on colorectal cancer outcome

BACKGROUND

Shortened postgraduate surgical training reforms, known as Calman, have altered delivery of surgical training in the UK with reduced working hours and training time aiming to produce a more subspecialised workforce.

AIMS

This study aims to compare rectal cancer surgical outcomes of Calman-trained consultants in a single institution to published data. Additionally, the study compared colorectal cancer surgical outcome between Calman-trained consultants (CTCs) and non-Calman consultants (NCTCs) in a national dataset.

METHODS

Local dataset Clinicopathological outcome of rectal cancer resection undertaken by CTCs in a single institution (2006-2010) were compared against NCTC counterparts. National dataset All elective colorectal cancer resections between 2004 and 2008 in English NHS hospitals were included. CTCs (present from 2004 onwards) were compared to NCTCs (present prior to 2004). Outcome measures included 30-day in-hospital mortality, reoperation and readmission rates.

RESULTS

Local dataset One hundred thirteen patients were operated under five CTC. The 30-day in-hospital mortality for CTCs (1%) was favourable compared to published rates (3-5%). Local recurrence rate (4.4%) was comparable to NCTC (3.6%). National dataset Between 2004 and 2008, 44,106 patients underwent elective colorectal resection. Multiple regression demonstrated CTC patients had a reduced length of stay and reduced reoperation rate. No difference in mortality and unplanned readmission rates were seen.

CONCLUSION

CTCs have similar safety outcome to NCTCs for colorectal cancer resection procedures. Further work is needed to assess the impact of further training reductions on clinical outcome.

Hierarchical multilevel analysis of increased caseload volume and postoperative outcome after elective colorectal surgery

BACKGROUND

The study aimed to explore the impact of surgeon and institution volume on outcome following colorectal surgery in England using multilevel hierarchical analysis.

METHODS

An observational study design was used. All patients undergoing primary elective colorectal resection between 2000 and 2008 were included from the Hospital Episode Statistics database. Consultant surgeons and hospitals were divided into tertiles (low, medium and high volume) according to their mean annual colorectal cancer resection caseload. Outcome measures examined were postoperative 30-day mortality, 28-day readmission and reoperation, and length of stay. Hierarchical multiple regression analysis adjusted for age, sex, co-morbidity, social deprivation, year of surgery, operation type and surgical approach.

RESULTS

A total of 109 261 elective cancer colorectal resections were included. High-volume consultant surgeons and hospitals were defined as performing more than 20·7 and 103·5 elective colorectal cancer procedures per year respectively. Consultant and hospital operative volumes increased throughout the study period. In hierarchical regression models, greater surgeon and institutional volume independently predicted only shorter length of hospital stay. No statistical association was observed between higher provider volume and postoperative mortality, 28-day reoperation or readmission rates.

CONCLUSION

Increasing elective colorectal cancer caseload alone may have marginal postoperative benefit.

The economic impact of anastomotic leakage after anterior resections in English NHS hospitals: are we adequately remunerating them?

AIM

Our aim was to determine the frequency and economic impact of anastomotic leakage (AL) at local and national levels in England.

METHOD

All patients who underwent AR in Oxford between 2007 and 2009 were evaluated for AL. Hospital Episode Statistics (HES) data were used to determine reoperation rates after elective AR (n = 23 388) in England between 2000 and 2008. Hospital episode remuneration costs were calculated by the local commissioning department and compared with Department of Health (DH) reference index costs.

RESULTS

The frequency of AL following anterior resection was 10.9% (31 out of 285) in Oxford. Laparotomy for leakage was performed in 5.6% of cases. The 30-day hospital mortality rate for all ARs was 2.1%, compared with 3.2% after AL. The national relaparotomy rate (within 28 days) and 30-day hospital mortality in English National Health Service (NHS) trusts following AR were 5.9% and 2.9%, respectively. Institutional remunerated tariffs (£6233 (SD ± 965)) were similar to DH reference costs (£6319 (SD ± 1830)) after uncomplicated AR. However, there was a significant (P = 0.008) discrepancy between the remunerated tariff for AL (£9605 (SD ± 6908)) and the actual cost (£17 220 (SD ± 9642)). AL resulted in an additional annual cost of approximately £1.1 million to £3.5 million when extrapolated nationally.

CONCLUSION

The estimated economic burden of anastomotic leakage following AR is approximately double that of the remunerated tariff.

Minimal-access colorectal surgery is associated with fewer adhesion-related admissions than open surgery

BACKGROUND

This study aimed to describe national intermediate-term admission rates for incisional hernia or clinically apparent adhesions following colorectal surgery, and to compare rates following laparoscopic and open approaches.

METHODS

Patients undergoing primary colorectal resection between 2002 and 2008 were included from the Hospital Episode Statistics database. Subsequent inpatient admissions were extracted for up to 3 years after the initial operation or to the end of the study period. Outcomes examined were admissions with a diagnosis of, or operative interventions for, incisional hernia or adhesions.

RESULTS

A total of 187 148 patients were included between 2002 and 2008, with median follow-up of 31·8 (interquartile range 13·1-35·3) months. Some 8885 (4·7 per cent) of these patients were admitted with a diagnosis of, or underwent a repair of, an incisional hernia. In multiple regression analysis, use of laparoscopy was not a predictor of operative intervention for incisional hernia (odds ratio 1·09, 95 per cent confidence interval (c.i.) 0·99 to 1·21; P = 0·083). Some 15 125 (8·1 per cent) of the patients were admitted with a diagnosis of adhesions or had a procedure for division of adhesions. Overall, 3·5 per cent (6637 of 187 148) of patients underwent adhesiolysis. Patients selected for a laparoscopic procedure had lower rates of admission for adhesions (6·3 per cent (692 of 11 013) for laparoscopic versus 8·2 per cent (14 433 of 176 135) for open surgery; P < 0·001) and reintervention for adhesions (2·8 per cent (305 of 11 013) versus 3·6 per cent (6325 of 176 135) respectively; P < 0·001) than those undergoing an open procedure. In multiple regression analysis, patients selected for a laparoscopic procedure had lower subsequent intervention rates for adhesions (odds ratio 0·80, 95 per cent c.i. 0·71 to 0·90; P < 0·001).

DISCUSSION

Patients undergoing colorectal resection who are selected for the laparoscopic approach have a lower risk of developing clinically significant adhesions.

Value of failure to rescue as a marker of the standard of care following reoperation for complications after colorectal resection

Background

Complication management appears to be of vital importance to differences in survival following surgery between surgical units. Failure-to-rescue (FTR) rates have not yet distinguished surgical from general medical complications. The aim of this study was to assess whether variability exists in FTR rates after reoperation for serious surgical complications following colorectal cancer resections in England.

Methods

The Hospital Episode Statistics (HES) database was used to identify patients undergoing primary resection for colorectal cancer between 2000 and 2008 in English National Health Service (NHS) trusts. Units were ranked into quintiles according to overall risk-adjusted mortality. Highest and lowest mortality quintiles were compared with respect to reoperation rates and FTR—surgical (FTR-S) rates. FTR-S was defined as the proportion of patients with an unplanned reoperation who died within the same admission.

Results

Some 144 542 patients undergoing resection for colorectal cancer in 150 English NHS trusts were included. On ranking according to risk-adjusted mortality, rates varied significantly between lowest and highest mortality quintiles (5·4 and 9·3 per cent respectively; P = 0·029). Lowest and highest mortality quintiles had equivalent adjusted reoperation rates (both 4·8 per cent; P = 0·211). FTR-S rates were significantly higher at units within the worst mortality quintile (16·8 versus 11·1 per cent; P = 0·002).

Conclusion

FTR-S rates differed significantly between English colorectal units, highlighting variability in ability to prevent death in this high-risk group. This variability may represent differences in serious surgical complication management. FTR-S represents a readily collectable marker of surgical complication management that is likely to be applicable to other surgical specialties.

Systematic review of discharge coding accuracy

INTRODUCTION

Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain.

METHODS

Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries.

RESULTS

Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3-92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3-94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7-88.7%). There was considerable variation in accuracy rates between studies (50.5-97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3-92.1%) to 96.0% (IQR: 89.3-96.3), P= 0.020.

CONCLUSION

Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making.

Volume analysis of outcome following restorative proctocolectomy

BACKGROUND

This observational study aimed to determine national provision and outcome following pouch surgery (restorative proctocolectomy, RPC) and to examine the effect of institutional and surgeon caseload on outcome.

METHODS

All patients undergoing primary RPC between April 1996 and March 2008 in England were identified from the administrative database Hospital Episode Statistics. Institutions and surgeons were categorized according to the total RPC caseload performed over the study interval.

RESULTS

Some 5771 primary elective pouch procedures were undertaken at 154 National Health Service hospital trusts. Median follow-up was 65 (interquartile range (i.q.r.) 28-106) months. The 30-day in-hospital mortality rate was 0·5 per cent and the 1-year overall mortality rate 1·5 per cent. Some 30·5 per cent of trusts performed fewer than two procedures per year, and 91·4 per cent of surgical teams (456 of 499) carried out 20 or fewer RPCs over 8 years. Median surgeon volume was 4 (i.q.r. 1-9) cases. Failure occurred in 6·4 per cent of cases. Low-volume surgeons operated on more patients at the extremes of age (P < 0·001) and a lower proportion with ulcerative colitis (P < 0·001). Older age, increasing co-morbidity, increasing social deprivation, and both lower provider and surgeon caseload were independent predictors of longer length of stay. Older patient age and low institutional volume status were independent predictors of failure.

CONCLUSION

Many English institutions and surgeons carry out extremely low volumes of RPC surgery. Case selection differed significantly between high- and low-volume surgeons. Institutional volume and older age were positively associated with increased pouch failure.

A colorectal perspective on voluntary submission of outcome data to clinical registries

BACKGROUND

The aim of the study was to identify outcome differences amongst patients undergoing resection of colorectal cancer at English National Health Service trusts using Hospital Episode Statistics (HES). A comparison was undertaken of trusts that submitted and those that did not submit, or submitted only poorly, voluntarily to a colorectal clinical registry, the National Bowel Cancer Audit Programme (NBOCAP).

METHODS

The NBOCAP data set was used to classify trusts according to submitter status. HES data were used for outcome analysis. Data for major resections of colorectal cancer performed between 1 August 2007 and 31 July 2008 were obtained from HES. Trusts not submitting data to NBOCAP and those submitting less than 10 per cent of their total workload were termed 'non-submitters'. HES data for 30-day mortality, length of stay and readmission rates were compared according to submitter and non-submitter status in multifactorial analyses.

RESULTS

A total of 17,722 patients were identified from HES for inclusion. Unadjusted 30-day in-hospital mortality rates were higher in non-submitting than in submitting trusts (5·2 versus 4·0 per cent; P = 0·005). Submitter status was independently associated with reduced 30-day mortality (odds ratio 0·76, 95 per cent confidence interval 0·61 to 0·96; P = 0·021) in regression analysis.

CONCLUSION

A higher postoperative mortality rate following resection of colorectal cancer was found in trusts that do not voluntarily report data to NBOCAP. Implications regarding the voluntary nature of submission to such registries should be reviewed if they are to be used for outcome benchmarking.

The influence of musical training on the perception of sequentially presented mistuned harmonics

The question of whether musical scales have developed from a processing advantage for frequency ratios based on small integers, i.e., ratios derived from relationships among harmonically related tones, is widely debated in musicology and music perception. In the extreme position, this processing advantage for these so-called "natural intervals" is assumed to be inherent, and to apply to sequentially presented tones. If this is the case, evidence for this processing advantage should show up in psychoacoustic experiments using listeners from the general population. This paper reports on replications and extensions of two studies from the literature. One [Lee and Green, J. Acoust. Soc. Am. 96, 716-725 (1994)] suggests that listeners from the general population can in fact determine whether sequentially presented tones are harmonically related. The other study [Houtgast, J. Acoust. Soc. Am. 60, 405-409 (1976)] is interpreted in different terms, but could be confounded by such an ability. The results of the replications and extensions, using listeners of known relative pitch proficiency, are consistent with the idea that only trained musicians can reliably determine whether sequentially presented tones are harmonically related.

Quantitative measurement of mammalian chromosome mitotic loss rates using the green fluorescent protein

We have measured the mitotic loss rates of mammalian chromosomes in cultured cells. The green fluorescent protein (GFP) gene was incorporated into a non-essential chromosome so that cells containing the chromosome fluoresced green, while those lacking it did not. The proportions of fluorescent and non-fluorescent cells were measured by fluorescence activated cell sorter (FACS) analysis. Loss rates ranged from 0.005% to 0.20% per cell division in mouse LA-9 cells, and from 0.02% to 0.40% in human HeLa cells. The rate of loss was elevated by treatment with aneugens, demonstrating that the system rapidly identifies agents which induce chromosome loss in mammalian cells.

A comparison of monotic and dichotic complex-tone pitch perception in listeners with hearing loss

The perception of fundamental pitch for two-harmonic complex tones was examined in musically experienced listeners with cochlear-based high-frequency hearing loss. Performance in a musical interval identification task was measured as a function of the average rank of the lowest harmonic for both monotic and dichotic presentation of the harmonics at 14 dB Sensation Level. Listeners with hearing loss demonstrated excellent musical interval identification at low fundamental frequencies and low harmonic numbers, but abnormally poor identification at higher fundamental frequencies and higher average ranks. The upper frequency limit of performance in the listeners with hearing loss was similar in both monotic and dichotic conditions. These results suggest that something other than frequency resolution per se limits complex-tone pitch perception in listeners with hearing loss.

Energy reflectance in the ear canal can exceed unity near spontaneous otoacoustic emission frequencies

There is some controversy in the literature over whether the so-called "active mechanism" or "cochlear amplifier" is actually a power amplifier that can produce an output signal with more power than its input, or whether it simply minimizes dissipative losses within the cochlea without providing an actual power gain greater than unity. A corollary of this controversy is whether spontaneous otoacoustic emissions (SOAEs) represent the output of a nonlinear oscillator mechanism, i.e., a power amplifier which can produce an oscillatory output signal in the absence of an input oscillatory signal, or whether they represent the output of a noise-driven, passive, nonlinear system. This paper describes measurements of energy reflectance, and acoustic impedance in the ear canals of human subjects with strong SOAEs. The reflectance, and the resistive and reactive parts of the acoustic impedance, all show a frequency fine structure which correlates with SOAE frequencies, and which becomes more pronounced at low stimulus levels. In some ears at some SOAE frequencies, energy reflectance exceeds unity, and correspondingly, acoustic resistance is negative. This result demonstrates that there is a power gain at these frequencies: The power reflected from the cochlea to the ear canal exceeds the power incident. It is also consistent with the theory that these SOAEs are produced by a nonlinear oscillator mechanism in the cochlea.

Evoked potentials in subjects at risk for Alzheimer's disease

Evoked potential (EP) changes accompanying dementing processes have been documented in a number of studies. However, EPs have not been studied in subjects who are at heightened risk for the development of Alzheimer's Disease (AD). Nineteen volunteers with no immediate family members with a history of AD and 33 healthy subjects with at least one first-degree relative with AD were studied. Of the 33 subjects with a positive family history of AD, the illness of the sick relative was classified as possible AD in 10 subjects, probable AD in 17 subjects, and definite (autopsy-proven) AD in 6 subjects. Mid-latency evoked potentials (P50, N100, and P200) and P300 event-related potentials were recorded in an oddball paradigm. The amplitudes of the P50 responses to the frequent stimuli and of the P300 responses were significantly higher in the subjects whose relatives had definite AD as compared with the other three groups. The amplitude of the N100 component was also larger in the same group, but the difference was only statistically significant from the group of healthy volunteers without a family history of AD. A process of increased sensitivity to incoming stimuli may be reflected in the increased P50, N100, and P300 amplitudes in the subjects at increased risk for developing AD.

Reliability of observer ratings in the assessment of personality disorders: a preliminary study

A 200-item, self-report personality disorder inventory (Coolidge Axis II Inventory; CATI) was administered to 52 married target subjects. Their spouses and a close friend completed a significant-other form about the targets. The mean correlation across all personality disorder scales was .51 for the targets-spouses, .36 for the targets-friends, and .41 for the spouses-friends. Twenty-eight target-spouse correlations were significant and ranged from .99 to -.40. The mean correlation for the individual 13 personality disorder scales was .46 for target-spouses and ranged from .63 for the histrionic scale to .27 for the paranoid scale. The results were interpreted as establishing a basis for significant other assessment of personality disorders.

Frequency and frequency-ratio resolution by possessors of absolute and relative pitch: examples of categorical perception

The methodology derived from the trace-context theory of intensity resolution (Durlach and Braida, 1969; Macmillan et al., 1988) was applied to resolution over an octave range along two continua: a sequential-frequency-ratio continuum for possessors of relative pitch (RP), and a pure-tone frequency continuum for possessors of absolute pitch (AP). The performance of both RP and AP possessors was exceptional in that total identification sensitivity along both continua was much greater than identification sensitivity along unidimensional psychophysical continua characterized by the 7 +/- 2 rule. In addition, the performance of RP possessors was exceptional in that, on average, total sensitivity for identification resolution was greater than sensitivity for resolution in discrimination. Finally, identification sensitivity between category prototypes (chromatic semits) along both continua was approximately the same as identification sensitivity between phonemic category prototypes along speech continua, despite the fact that both the discrimination ranges and the total number of categories are much larger for the two pitch continua.

Pressure transfer function and absorption cross section from the diffuse field to the human infant ear canal

The diffuse-field pressure transfer function from a reverberant field to the ear canal of human infants, ages 1, 3, 6, 12, and 24 months, has been measured from 125-10700 Hz. The source was a loudspeaker using pink noise, and the diffuse-field pressure and the ear-canal pressure were simultaneously measured using a spatial averaging technique in a reverberant room. The results in most subjects show a two-peak structure in the 2-6-kHz range, corresponding to the ear-canal and concha resonances. The ear-canal resonance frequency decreases from 4.4 kHz at age 1 month to 2.9 kHz at age 24 months. The concha resonance frequency decreases from 5.5 kHz at age 1 month to 4.5 kHz at age 24 months. Below 2 kHz, the diffuse-field transfer function shows effects due to the torsos of the infant and parent, and varies with how the infant is held. Comparisons are reported of the diffuse-field absorption cross section for infants relative to adults. This quantity is a measure of power absorbed by the middle ear from a diffuse sound field, and large differences are observed in infants relative to adults. The radiation efficiencies of the infant and the adult ear are small at low frequencies, near unity at midfrequencies, and decrease at higher frequencies. The process of ear-canal development is not yet complete at age 24 months. The results have implications for experiments on hearing in infants.

Longitudinal measurements of spontaneous otoacoustic emissions in infants

It has previously been shown [E. M. Burns, K. H. Arehart, and S. L. Campbell, J. Acoust. Soc. Am. 91, 1575-1581 (1992)] that both the overall prevalence of spontaneous otoacoustic emissions (SOAEs) and most of the various gender- and ear-related prevalence tendencies are not significantly different in 1-month-olds and adults. However, large differences were found between the neonates and adults in the distributions of the frequencies and levels of SOAEs. Both the average level and the median frequency were significantly higher in infants. To obtain longitudinal SOAE data, infants from this original group of 1-month-olds were tested at ages 3, 6, 12, and 24 months. In general, individual SOAEs decrease in level with age, and high-frequency SOAEs tend to show the largest decreases. No substantial shifts occur in the frequencies of individual SOAEs. The frequency and level distributions at 24 months of age are still not adult-like. SOAEs which show short-term instabilities in frequency and/or amplitude at 1 month of age typically continue to evidence such instabilities at later ages. These results suggest the cochlea is adult-like at birth, and imply that the observed SOAE changes reflect developmental changes in the external and middle ear.

Effects of contralateral acoustic stimulation on spontaneous otoacoustic emissions

Spontaneous otoacoustic emissions (SOAEs) were measured in the ear canal of adult humans prior to, during, and following presentation of tonal and broadband stimuli to the contralateral ear. Tones were presented at a fixed level at ten frequencies relative to the SOAE. Broadband noise was presented at eight levels, from 6 to 76 dB SPL. Shifts in SOAE frequency and amplitude were observed for some subjects, for some tone conditions. Frequency shifts were always positive, whereas amplitude shifts were variable. No apparent pattern of tuning was seen, such that tones with a particular frequency relationship to the SOAEs induced greater changes in the SOAEs. Systematic changes in frequency and amplitude of SOAEs were observed for increasing level of broadband noise for all subjects. Results are discussed with respect to possible mechanism(s) responsible for the alterations in SOAEs: Transcranial conduction; the olivocochlear system; and/or the middle-ear reflex arc.

Ear-canal impedance and reflection coefficient in human infants and adults

The ear-canal impedance and reflection coefficient were measured in an adult group and in groups of infants of age 1, 3, 6, 12, and 24 months over frequency range 125-10,700 Hz. The development of the external ear canal and middle ear strongly affect input impedance and reflection coefficient responses, and this development is not yet complete at age 24 months. Contributing factors include growth of the area and length of the ear canal, a resonance in the ear-canal walls of younger infants, and a probable influence of growth of the middle-ear cavities. The middle-ear compliance is lower in infants than adults, and the middle-ear resistance is higher. The power transfer into the middle ear of the infant is much less than into that of the adult. Such differences in power transfer directly influence both behavioral and physiological measurements of hearing. The difficulties of interpretation of neonatal tympanograms are shown to be a consequence of ear-canal wall vibration. Impedance and reflectance measurements in the 2-4-kHz range are recommended as a potentially useful clinical tool for circumventing these difficulties.

Voluntary contraction of middle ear muscles: effects on input impedance, energy reflectance and spontaneous otoacoustic emissions

Two types of measurements were performed on a subject able to voluntarily contract her middle ear muscles (MEM). First, wideband measurements (0-11 kHz) of middle ear input impedance and energy reflectance were obtained when the subject was relaxed and when she contracted her MEM. The changes in impedance observed with voluntary MEM contraction were similar to those reported in the literature for acoustically-elicited MEM contractions. The energy reflectance increased for frequencies below about 4 kHz. Second, the effects of voluntary MEM contraction on the frequencies and levels of spontaneous otoacoustic emissions (SOAEs) were measured and compared to effects evoked by contralateral acoustic stimulation. Effects on SOAEs appear to be a more sensitive indicator of MEM activity than changes in impedance, and the effects due to voluntary MEM contraction were qualitatively similar to those evoked by contralateral acoustic stimulation. These results suggest that in subjects with normally-functioning middle ears, only some effects on otoacoustic emissions caused by contralateral stimuli whose levels are below the contralateral acoustic reflex threshold can be unequivocally attributed to the action of cochlear efferents. The temporal aspects of SOAE frequency shifts caused by voluntary contraction of MEM show that voluntary contraction fatigues rapidly over a time period of tens of seconds.

Prevalence of spontaneous otoacoustic emissions in neonates

The prevalence of spontaneous otoacoustic emissions (SOAEs) was measured in a group of 100 neonates and in a group of 50 normal-hearing young adults. The prevalence of SOAEs in the adult group (0.62) is at the high end of the range of prevalences reported in other surveys of adult SOAEs based on measurements using similar microphones. The prevalence of SOAEs in neonates (0.64) is not significantly different from that in adults. The various tendencies that have been found to be significant in the pooled results of other surveys are also evident in our adult group: more SOAEs in right ears, a higher prevalence of SOAEs in females, and a dependence between ears for the occurrence of SOAEs. The above-mentioned tendencies are also significant in the infant data. The major differences between the infant and adult results are the predominant SOAE frequency range and the average levels of SOAEs. The majority of adult SOAEs are between 1.0 and 2.0 kHz, whereas the majority of neonatal SOAEs are between 2.5 and 5.0 kHz. The average SOAE level is -2.6 dB SPL for adults and 8.5 dB SPL for infants.

Pathophysiology and etiology of Alzheimer's disease

Morphologic, neurochemical, and physiologic alterations in the brain constitute the biologic correlates of aging and of progressive, irreversible deterioration in mental function and personality characteristics of Alzheimer's disease.

Right vs. left hemispheric blood-brain barrier permeability in schizophrenia: a dynamic computed tomographic study

Dynamic computerized tomographic brain scanning was used to make determinations of mean cerebral tissue nonenhanced density and contrast-enhanced density in 10 bilateral brain regions in 10 psychotic subjects. Asymmetry of both nonenhanced and contrast-enhanced density was observed; left regional nonenhanced values were higher than right, whereas contrast-enhanced density values were higher on the right than on the left. No significant differences were observed in arterial mean transit time (AMTT) between right and left middle cerebral artery branches or in capillary or tissue mean transit time (CMTT) in the middle temporal cortex. However, corrected CMTT (CCMTT), i.e., CMTT minus AMTT, may have been prolonged in five subjects either on the left or right, or in both homologous regions. Only 2 of 10 subjects exhibited anterior-posterior (AP) gradients that resembled to some extent the hyperfrontal pattern reported in normal subjects by other investigators with different techniques.

Rapid dynamic CT scanning to distinguish schizophrenic from normal subjects

Rapid dynamic computerized axial tomography (CT) density-time curves were used to detect abnormal brain regions in groups of controls and DSM-III diagnosed schizophrenics. Density-time curves were designated as plateau curves if, following a bolus injection of contrast material, they exhibited a plateau from the peak value rather than a decrease. Five of the 10 schizophrenics versus none of the 11 controls were found to possess two or more plateau curves. The physiological basis for the plateau curves is not known, but an increase in blood-brain-barrier permeability could be involved.

Ethanol exposure during brain ontogeny: some long-term effects

The timing, intensity, and duration of the period of maximal susceptibility of the developing brain to ethanol have not been clearly elucidated. This study was designed to determine whether a lower blood ethanol concentration (BEC) or a brief exposure during the brain growth spurt in the rat might cause permanent brain damage. Two doses of ethanol (4 g/kg body weight daily during days 6-16 after birth and 6 g/kg on day 6 only after birth) were used. Significant differences in whole brain weight, a disproportionately decreased cerebellar weight, altered balancing ability, and a decreased number of cerebellar cells were observed on days 17 and 70 postnatally in both ethanol-treated groups as compared with controls. Cerebellar weight a both ages were more markedly affected in animals treated only on day 6 postnatally than in animals treated throughout the major portion of the brain growth spurt. These results suggest that episodic exposure to ethanol during peak brain growth may be just as devastating to brain development as chronic exposure throughout the major portion of the brain growth spurt.

Pure-tone pitch anomalies. II. Pitch-intensity effects and diplacusis in impaired ears

Pitch-intensity functions and psychophysical tuning curves (PTC's) were measured in ten listeners with sensorineural impairments of presumed cochlear origin. Masking patterns, frequency jnd's, diplacusis measurements, and octave adjustments were also obtained for selected conditions in selected listeners. The results showed a tendency for increased frequency jnd's and increased pitch-matching variability in frequency regions where frequency resolution, as determined by PTC Q10 estimates, was degraded. The results also showed exaggerated pitch-level effects, both in regions where frequency resolution was degraded and, in many cases, in regions where thresholds and frequency resolution were apparently normal. The usual manifestation of exaggerated pitch-level effect was an abnormally large negative pitch shift with increasing level, particularly at low frequencies. The limited data from diplacusis measurements and octave adjustments suggest that the exaggerated negative pitch shifts are the consequence of a large increase in pitch at low stimulus levels which "recruits" at higher levels. These results are difficult to explain with simple tonotopic models, or presently formulated temporal models, of pure-tone pitch encoding.

Incidence of spontaneous otoacoustic emissions in children and infants

Whereas some evidence indicates that spontaneous otoacoustic emissions (SOAEs) may be a manifestation of the normal functioning of an active feedback mechanism in the cochlea, other evidence suggests that emissions may be the result of the interaction of such a feedback mechanism with localized outer-hair-cell damage. The present study surveyed the incidence of SOAEs in children and infants. If SOAEs are correlated with outer-hair-cell damage, the incidence of SOAEs might be expected to be lower in these two groups than in adults. The results showed no difference in the incidence of SOAEs with age. They also showed a significant tendency for a higher incidence of SOAEs in females than in males.

Interactions among spontaneous otoacoustic emissions. I. Distortion products and linked emissions

Spontaneous otoacoustic emissions (SOAEs) can be recorded from human ears with a sensitive microphone in the ear canal. The evidence to date strongly indicates that the origin of these emissions in an active electro-mechanical process at the basilar membrane level. In this report we present data on interactions among SOAEs in ears with multiple SOAEs, including: intermodulation distortion products, mutual suppression, and noncontiguous-linked SOAEs which apparently share energy between two quasi-stable states. These results demonstrate the highly nonlinear and extremely complex nature of the active process, and present a challenge for mathematical modeling of the mechanisms involved.

Ethanol in preweanling rats with dams: body temperature unaffected

At an ambient temperature of 24 degrees C, the neonatal rat was found to exhibit poikilothermic characteristics if separated from the dam. On day one after birth, at one hour after separation from dams, the body temperature in rat pups was found to be identical with ambient temperature. Preweanling pups, under these circumstances, were unable to maintain a constant body temperature prior to day 19 postnatally. No differences were observed in body temperatures of rat pups treated chronically (days 6-16 postnatally) with ethanol 4 g/kg body weight (in two 2 g/kg doses three hours apart), as compared with isocaloric isovolumetric milk-, or sham-treated control groups. A significantly lower temperature was observed only at 105 minutes after the first treatment in a group of rats acutely treated (one day only) with ethanol on day 22 postnatally as compared with an isovolumetric water control group. In adult rats, also treated acutely with ethanol, a significant hypothermic response occurred at 105 minutes after the first 2 g/kg dose and persisted during the remainder of the observation period. This study shows that body temperature was unaffected in neonatal Sprague-Dawley rats left with their dams after intubation with ethanol 4 g/kg body weight. Therefore any brain biochemical and/or structural alterations resulting from ethanol exposure, using this animal model, are not due to an ethanol induced hypothermic response.

The effects of ethanol exposure during the brain growth spurt in rats

The purpose of this study was to determine whether micromorphological changes occur at a low level of ethanol exposure previously shown by us to induce alterations in synaptosomal biochemistry. The results suggest that 4 g ethanol per kg body weight daily throughout the brain growth spurt causes no significant structural changes in the cerebellum, lobule IX, at the light and electron microscopic levels. Although ethanol- and isocaloric sucrose-treated groups did not differ from each other in cumulative percent body weight gain throughout the treatment period, both groups differed significantly in this parameter from isocaloric milk-treated and "handled" control groups. On the day following completion of the treatment period, brain weight in the ethanol-treated group was significantly less than that of all other groups. Further, the results indicate that isocaloric sucrose "pair feeding" is contraindicated in postnatal studies and that nutritional status is better controlled by daily gavage of neonates than by other methods currently used in ethanol studies in postnatal animals.

A comparison of variability among measurements of subjective tinnitus and objective stimuli

8 patients with subjective tinnitus were trained in pitch-matching, loudness-matching, and simultaneous-masking tasks using narrow-band noise and/or pure-tone stimuli. Extensive pitch-matching, loudness-matching and masking measurements were then obtained for their tinnitus, after which the same measurements were obtained for objective stimuli which approximated the frequency and intensity of the tinnitus. Variability for pitch and loudness matching to tinnitus was extremely large relative to the same measurements for objective stimuli. This was particularly true for pitch-matching where even the most consistent patients showed variability for matches to their tinnitus which was an order of magnitude greater than for matches to objective stimuli in the same frequency region. No evidence of frequency-specific masking of tinnitus was seen in any of the patients although such evidence was obtained for the masking of objective stimuli. The results suggest that the large variability in matches to tinnitus, and the lack of normal frequency-specific masking of tinnitus in these patients may reflect interactions at levels higher than the end-organ rather than a degradation in peripheral auditory function.

Diabetes mellitus and pregnancy

Pregnancy complicated by diabetes has many risks to the mother and her infant. Tight glycemic control and close fetal surveillance have helped to reduce the incidence of neonatal complications. The nurse as a member of the interdisciplinary perinatal team is in a key position to provide continuity of care and supportive attention to the patient and her family.

Pure tone pitch perception and low-frequency hearing loss

Pitch perception for pure tones was investigated in a group of listeners with low-frequency sensorineural hearing loss. Pitch judgments from each listener were compared with results from psycho-acoustic tasks which provide information on the "place" of cochlear response. The pitch measures employed were: (1) binaural pure-tone pitch matching in a listener with unilateral hearing loss, (2) octave judgments in listeners with musical ability, and (3) pitch-intensity functions in other listeners. Cochlear place of response was inferred from psychophysical tuning curves (PTC's). Two distinct types of PTC's for low-frequency probe tones were observed. Three listeners demonstrated "abnormally tuned" PTC's. For these listeners the frequencies that were most effective at masking the probe were considerably higher than the probe frequency. The three remaining listeners demonstrated "normally tuned" PTC's. Listeners with abnormally tuned PTC's were suspected of having an extremely abnormal place of response for low-frequency tones; this response pattern being located more toward the base of the cochlea than in the listeners with normally tuned PTC's. Sensitivity thresholds measured in the presence of high-pass masking noise supported this hypothesis. Small pitch-frequency irregularities were observed in many listeners, although they were not consistently related to the inferred place of response for that frequency. The individual listeners' pitch judgments failed to distinguish between two types of PTC's. In particular, listeners who demonstrated abnormally tuned PTC's did not exhibit correspondingly large pitch irregularities. These results are difficult to explain on the basis of a classical "place" theory of pitch perception.

Pure-tone anomalies. I. Pitch-intensity effects and diplacusis in normal ears

Pitch-intensity functions were obtained in both ears of five normal-hearing subjects, together with measurements of binaural diplacusis as a function of intensity. The results show that pitch-intensity functions are often significantly different in the two ears of a given subject at a given frequency. Furthermore, for each subject and frequency condition tested, an intensity existed for which no significant diplacusis was found. For these conditions, therefore, binaural diplacusis as a function of intensity could be accounted for by the interaural differences in pitch-intensity functions. Forward-masking patterns (FMP's) as a function of intensity were also obtained in both ears of several subjects. The FMP's were compared with pitch-intensity functions, obtained for the same conditions, for evidence of a covariation in the direction of shifts in masking patterns as a function of intensity with the direction of pitch shifts as a function of intensity. No convincing evidence of such a covariation was found. The implications of the results of these experiments are discussed relative to the question of temporal versus tonotopic coding of pure-tone pitch.

Changes with age in cerebral capillary morphology

Age related alterations in cerebral capillary morphology were investigated in 4-, 10-, and 20-year-old Macaque monkeys and in 1-, 14-, 35-, 180-, and 800-day-old Sprague-Dawley rats. This study revealed the following changes with increasing age: a significant decrease in cerebral capillary wall thickness in frontal cortex in monkeys but not in rats; a significant increase in the thickness of basal lamina (BL) of cerebral capillaries in rats but not in monkeys, however there was a marked increase in this parameter in the monkey between 4 and 10 years of age; a significant decline in cerebral capillary endothelial mitochondrial content in monkeys whereas a significant decline in this parameter in rats was found only when the peak content at 35 days was contrasted with that at 800 days of age; and, aberrant tight junctions and thickened BL in one of five 20-year-old monkeys. These findings suggest impairment of barrier characteristics of cerebral capillaries with increasing age in both the rat and the monkey.