Crosstalk Between NK Cell Receptors and Tumor Membrane Hsp70-Derived Peptide: A Combined Computational and Experimental Study

Natural killer (NK) cells are central components of the innate immunity system against cancers. Since tumor cells have evolved a series of mechanisms to escape from NK cells, developing methods for increasing the NK cell antitumor activity is of utmost importance. It is previously shown that an ex vivo stimulation of patient-derived NK cells with interleukin (IL)-2 and Hsp70-derived peptide TKD (TKDNNLLGRFELSG, aa450-461) results in a significant upregulation of activating receptors including CD94 and CD69 which triggers exhausted NK cells to target and kill malignant solid tumors expressing membrane Hsp70 (mHsp70). Considering that TKD binding to an activating receptor is the initial step in the cytolytic signaling cascade of NK cells, herein this interaction is studied by molecular docking and molecular dynamics simulation computational modeling. The in silico results showed a crucial role of the heterodimeric receptor CD94/NKG2A and CD94/NKG2C in the TKD interaction with NK cells. Antibody blocking and CRISPR/Cas9-mediated knockout studies verified the key function of CD94 in the TKD stimulation and activation of NK cells which is characterized by an increased cytotoxic capacity against mHsp70 positive tumor cells via enhanced production and release of lytic granules and pro-inflammatory cytokines.

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

Isothiocyanates in medicine: A comprehensive review on phenylethyl-, allyl-, and benzyl-isothiocyanates

In recent years, isothiocyanates (ITCs), bioactive compounds primarily derived from Brassicaceae vegetables and herbs, have gained significant attention within the biomedical field due to their versatile biological effects. This comprehensive review provides an in-depth exploration of the therapeutic potential and individual biological mechanisms of the three specific ITCs phenylethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC), and benzyl isothiocyanate (BITC), as well as their collective impact within the formulation of ANGOCIN® Anti-Infekt N (Angocin). Angocin comprises horseradish root (Armoracia rusticanae radix, 80 mg) and nasturtium (Tropaeoli majoris herba, 200 mg) and is authorized for treating inflammatory diseases affecting the respiratory and urinary tract. The antimicrobial efficacy of this substance has been confirmed both in vitro and in various clinical trials, with its primary effectiveness attributed to ITCs. PEITC, AITC, and BITC exhibit a wide array of health benefits, including potent anti-inflammatory, antioxidant, and antimicrobial properties, along with noteworthy anticancer potentials. Moreover, we highlight their ability to modulate critical biochemical pathways, such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and signal transducer and activator of transcription (STAT) pathways, shedding light on their involvement in cellular apoptosis and their intricate role to guide immune responses.

Pure Wisdom or Potemkin Villages? A Comparison of ChatGPT 3.5 and ChatGPT 4 on USMLE Step 3 Style Questions: Quantitative Analysis

BACKGROUND

The United States Medical Licensing Examination (USMLE) has been critical in medical education since 1992, testing various aspects of a medical student's knowledge and skills through different steps, based on their training level. Artificial intelligence (AI) tools, including chatbots like ChatGPT, are emerging technologies with potential applications in medicine. However, comprehensive studies analyzing ChatGPT's performance on USMLE Step 3 in large-scale scenarios and comparing different versions of ChatGPT are limited.

OBJECTIVE

This paper aimed to analyze ChatGPT's performance on USMLE Step 3 practice test questions to better elucidate the strengths and weaknesses of AI use in medical education and deduce evidence-based strategies to counteract AI cheating.

METHODS

A total of 2069 USMLE Step 3 practice questions were extracted from the AMBOSS study platform. After including 229 image-based questions, a total of 1840 text-based questions were further categorized and entered into ChatGPT 3.5, while a subset of 229 questions were entered into ChatGPT 4. Responses were recorded, and the accuracy of ChatGPT answers as well as its performance in different test question categories and for different difficulty levels were compared between both versions.

RESULTS

Overall, ChatGPT 4 demonstrated a statistically significant superior performance compared to ChatGPT 3.5, achieving an accuracy of 84.7% (194/229) and 56.9% (1047/1840), respectively. A noteworthy correlation was observed between the length of test questions and the performance of ChatGPT 3.5 (ρ=-0.069; P=.003), which was absent in ChatGPT 4 (P=.87). Additionally, the difficulty of test questions, as categorized by AMBOSS hammer ratings, showed a statistically significant correlation with performance for both ChatGPT versions, with ρ=-0.289 for ChatGPT 3.5 and ρ=-0.344 for ChatGPT 4. ChatGPT 4 surpassed ChatGPT 3.5 in all levels of test question difficulty, except for the 2 highest difficulty tiers (4 and 5 hammers), where statistical significance was not reached.

CONCLUSIONS

In this study, ChatGPT 4 demonstrated remarkable proficiency in taking the USMLE Step 3, with an accuracy rate of 84.7% (194/229), outshining ChatGPT 3.5 with an accuracy rate of 56.9% (1047/1840). Although ChatGPT 4 performed exceptionally, it encountered difficulties in questions requiring the application of theoretical concepts, particularly in cardiology and neurology. These insights are pivotal for the development of examination strategies that are resilient to AI and underline the promising role of AI in the realm of medical education and diagnostics.

An ACS-NSQIP Data Analysis of 30-Day Outcomes Following Surgery for Bell's Palsy

BACKGROUND

There exists a paucity of large-scale, multi-institutional studies that investigate the outcomes of surgery for Bell's palsy (BP). Here, we utilize a large, multi-institutional database to study the risk factors and early-stage outcomes following surgical procedures in BP.

METHODS

We reviewed the American College of Surgeons National Surgical Quality Improvement Program database (2008-2019) to identify patients who underwent surgery for the diagnosis of BP. We extracted data on comorbidities and preoperative blood values, and 30-day postoperative outcomes.

RESULTS

Two hundred fifty-seven patients who underwent surgery for BP symptoms over the 12-year review period were identified. Muscle grafts (n=50; 19%) and fascial grafts (n=48; 19%) accounted for the majority of procedures. The most common comorbidities were hypertension (n=89; 35%) and obesity (n=79; 31%). Complications occurred in 26 (10.1%) cases. Additionally, length of hospital stay was significantly associated with both surgical and medical complications (3.9±4.7 versus 1.5±2.0; P <0.01) and (3.2±3.8 versus 1.4±2.0; P <0.01), respectively. Preoperative creatinine, blood urea nitrogen, and alkaline phosphatase were identified as potential predictors of poor postoperative outcomes.

CONCLUSION

Based on multi-institutional analysis, complication rates following surgery for BP were found to be overall low and seen to correlate with length of hospital stay. Reoperations and readmissions were the most frequent complications after surgery for BP. The preoperative evaluation of routine laboratory values may help refine patient eligibility and risk stratification. In addition, our findings call for future large-scale prospective studies in the field of facial palsy surgery to further improve the quality of care and optimize perioperative protocols.

Diagnosing lagophthalmos using artificial intelligence

Lagophthalmos is the incomplete closure of the eyelids posing the risk of corneal ulceration and blindness. Lagophthalmos is a common symptom of various pathologies. We aimed to program a convolutional neural network to automatize lagophthalmos diagnosis. From June 2019 to May 2021, prospective data acquisition was performed on 30 patients seen at the Department of Plastic, Hand, and Reconstructive Surgery at the University Hospital Regensburg, Germany (IRB reference number: 20-2081-101). In addition, comparative data were gathered from 10 healthy patients as the control group. The training set comprised 826 images, while the validation and testing sets consisted of 91 patient images each. Validation accuracy was 97.8% over the span of 64 epochs. The model was trained for 17.3 min. For training and validation, an average loss of 0.304 and 0.358 and a final loss of 0.276 and 0.157 were noted. The testing accuracy was observed to be 93.41% with a loss of 0.221. This study proposes a novel application for rapid and reliable lagophthalmos diagnosis. Our CNN-based approach combines effective anti-overfitting strategies, short training times, and high accuracy levels. Ultimately, this tool carries high translational potential to facilitate the physician's workflow and improve overall lagophthalmos patient care.

1,8-cineole (eucalyptol): A versatile phytochemical with therapeutic applications across multiple diseases

1,8-cineole (Eucalyptol), a naturally occurring compound derived from botanical sources such as eucalyptus, rosemary, and camphor laurel, has a long history of use in traditional medicine and exhibits an array of biological properties, including anti-inflammatory, antioxidant, antimicrobial, bronchodilatory, analgesic, and pro-apoptotic effects. Recent evidence has also indicated its potential role in managing conditions such as Alzheimer's disease, neuropathic pain, and cancer. This review spotlights the health advantages of 1,8-cineole, as demonstrated in clinical trials involving patients with respiratory disorders, including chronic obstructive pulmonary disease, asthma, bronchitis, and rhinosinusitis. In addition, we shed light on potential therapeutic applications of 1,8-cineole in various conditions, such as depression, epilepsy, peptic ulcer disease, diarrhea, cardiac-related heart diseases, and diabetes mellitus. A comprehensive understanding of 1,8-cineole's pharmacodynamics and safety aspects as well as developing effective formulations, might help to leverage its therapeutic value. This thorough review sets the stage for future research on diverse health benefits and potential uses of 1,8-cineole in tackling complex medical conditions.

From bench to bedside - current clinical and translational challenges in fibula free flap reconstruction

Fibula free flaps (FFF) represent a working horse for different reconstructive scenarios in facial surgery. While FFF were initially established for mandible reconstruction, advancements in planning for microsurgical techniques have paved the way toward a broader spectrum of indications, including maxillary defects. Essential factors to improve patient outcomes following FFF include minimal donor site morbidity, adequate bone length, and dual blood supply. Yet, persisting clinical and translational challenges hamper the effectiveness of FFF. In the preoperative phase, virtual surgical planning and artificial intelligence tools carry untapped potential, while the intraoperative role of individualized surgical templates and bioprinted prostheses remains to be summarized. Further, the integration of novel flap monitoring technologies into postoperative patient management has been subject to translational and clinical research efforts. Overall, there is a paucity of studies condensing the body of knowledge on emerging technologies and techniques in FFF surgery. Herein, we aim to review current challenges and solution possibilities in FFF. This line of research may serve as a pocket guide on cutting-edge developments and facilitate future targeted research in FFF.

ChatGPT's quiz skills in different otolaryngology subspecialties: an analysis of 2576 single-choice and multiple-choice board certification preparation questions

PURPOSE

With the increasing adoption of artificial intelligence (AI) in various domains, including healthcare, there is growing acceptance and interest in consulting AI models to provide medical information and advice. This study aimed to evaluate the accuracy of ChatGPT's responses to practice quiz questions designed for otolaryngology board certification and decipher potential performance disparities across different otolaryngology subspecialties.

METHODS

A dataset covering 15 otolaryngology subspecialties was collected from an online learning platform funded by the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery, designed for board certification examination preparation. These questions were entered into ChatGPT, with its responses being analyzed for accuracy and variance in performance.

RESULTS

The dataset included 2576 questions (479 multiple-choice and 2097 single-choice), of which 57% (n = 1475) were answered correctly by ChatGPT. An in-depth analysis of question style revealed that single-choice questions were associated with a significantly higher rate (p < 0.001) of correct responses (n = 1313; 63%) compared to multiple-choice questions (n = 162; 34%). Stratified by question categories, ChatGPT yielded the highest rate of correct responses (n = 151; 72%) in the field of allergology, whereas 7 out of 10 questions (n = 65; 71%) on legal otolaryngology aspects were answered incorrectly.

CONCLUSION

The study reveals ChatGPT's potential as a supplementary tool for otolaryngology board certification preparation. However, its propensity for errors in certain otolaryngology areas calls for further refinement. Future research should address these limitations to improve ChatGPT's educational use. An approach, with expert collaboration, is recommended for the reliable and accurate integration of such AI models.

Sailing the Seven Seas: A Multinational Comparison of ChatGPT's Performance on Medical Licensing Examinations

PURPOSE

The use of AI-powered technology, particularly OpenAI's ChatGPT, holds significant potential to reshape healthcare and medical education. Despite existing studies on the performance of ChatGPT in medical licensing examinations across different nations, a comprehensive, multinational analysis using rigorous methodology is currently lacking. Our study sought to address this gap by evaluating the performance of ChatGPT on six different national medical licensing exams and investigating the relationship between test question length and ChatGPT's accuracy.

METHODS

We manually inputted a total of 1,800 test questions (300 each from US, Italian, French, Spanish, UK, and Indian medical licensing examination) into ChatGPT, and recorded the accuracy of its responses.

RESULTS

We found significant variance in ChatGPT's test accuracy across different countries, with the highest accuracy seen in the Italian examination (73% correct answers) and the lowest in the French examination (22% correct answers). Interestingly, question length correlated with ChatGPT's performance in the Italian and French state examinations only. In addition, the study revealed that questions requiring multiple correct answers, as seen in the French examination, posed a greater challenge to ChatGPT.

CONCLUSION

Our findings underscore the need for future research to further delineate ChatGPT's strengths and limitations in medical test-taking across additional countries and to develop guidelines to prevent AI-assisted cheating in medical examinations.

Bilateral Keloid Formation after Otoplasty in the Presence of Prolonged Mask Wearing

Prominent ears are the most frequently observed congenital deformity of the head and neck. Various techniques have been proposed for their aesthetic correction. Typically, surgical treatment for protruding ears involves a combination of suture, cutting, and scoring techniques. Herein, we present the clinical case of an 11-year-old child who developed bilateral keloid formations 12 months after otoplasty. Keloids and hypertrophic scars can result from extensive retroauricular skin excisions that do not allow for tension-free wound closure. In addition, skin tension and friction on immature surgical scars are common risk factors for keloid formation. To comply with school guidelines aimed at reducing the transmission of SARS-CoV-2, the patient has consistently worn FFP2 masks with ear loops positioned behind the concha. Although masks play a critical role in preventing the spread of infectious diseases, they can lead to friction in the postauricular area. In light of the presented case, it is important to examine potential cofactors that may contribute to keloid formation after otoplasty, as well as suggest a strategy to safeguard the retroauricular scar.

Unraveling the Role of Epithelial-Mesenchymal Transition in Adenoid Cystic Carcinoma of the Salivary Glands: A Comprehensive Review

Salivary adenoid cystic carcinoma (SACC) is considered a challenging malignancy; it is characterized by a slow-growing nature, yet a high risk of recurrence and distant metastasis, presenting significant hurdles in its treatment and management. At present, there are no approved targeted agents available for the management of SACC and systemic chemotherapy protocols that have demonstrated efficacy remain to be elucidated. Epithelial-mesenchymal transition (EMT) is a complex process that is closely associated with tumor progression and metastasis, enabling epithelial cells to acquire mesenchymal properties, including increased mobility and invasiveness. Several molecular signaling pathways have been implicated in the regulation of EMT in SACC, and understanding these mechanisms is crucial to identifying new therapeutic targets and developing more effective treatment approaches. This manuscript aims to provide a comprehensive overview of the latest research on the role of EMT in SACC, including the molecular pathways and biomarkers involved in EMT regulation. By highlighting the most recent findings, this review offers insights into potential new therapeutic strategies that could improve the management of SACC patients, especially those with recurrent or metastatic disease.

Postoperative free flap monitoring in reconstructive surgery-man or machine?

Free tissue transfer is widely used for the reconstruction of complex tissue defects. The survival of free flaps depends on the patency and integrity of the microvascular anastomosis. Accordingly, the early detection of vascular comprise and prompt intervention are indispensable to increase flap survival rates. Such monitoring strategies are commonly integrated into the perioperative algorithm, with clinical examination still being considered the gold standard for routine free flap monitoring. Despite its widespread acceptance as state of the art, the clinical examination also has its pitfalls, such as the limited applicability in buried flaps and the risk of poor interrater agreement due to inconsistent flap (failure) appearances. To compensate for these shortcomings, a plethora of alternative monitoring tools have been proposed in recent years, each of them with inherent strengths and limitations. Given the ongoing demographic change, the number of older patients requiring free flap reconstruction, e.g., after cancer resection, is rising. Yet, age-related morphologic changes may complicate the free flap evaluation in elderly patients and delay the prompt detection of clinical signs of flap compromise. In this review, we provide an overview of currently available and employed methods for free flap monitoring, with a special focus on elderly patients and how senescence may impact standard free flap monitoring strategies.

Protecting sleep quality in later life: a pilot study of bed restriction and sleep hygiene

We tested two interventions for improving sleep consolidation and depth in normal elderly participants: a modification of sleep-restriction therapy and sleep-hygiene education. Twenty-one elderly participants without sleep disorders were randomized to sleep hygiene plus bed restriction (i.e., restricting time in bed by 30 minutes nightly for one year) or to sleep hygiene alone. Participants in the bed-restriction group showed a median increase in sleep efficiency of 6.1% versus 1.8% in participants receiving sleep hygiene instruction, and an increase in allnight delta EEG power. Self-reported mood on awakening in the morning showed greater improvement over the first eight weeks in the sleep-hygiene condition. The use of sleep hygiene was associated with initial improvement in daytime well-being, whereas bed restriction led to sustained improvements in sleep continuity and sleep depth.

Maintenance nortriptyline effects on electroencephalographic sleep in elderly patients with recurrent major depression: double-blind, placebo- and plasma-level-controlled evaluation

Our aim was to contrast the effects of maintenance nortriptyline and placebo on electroencephalographic sleep measures in elderly recurrent depressives who survived 1-year without recurrence of depression. Patients on nortriptyline took longer to fall asleep and did not maintain sleep better than patients on placebo; however, maintenance nortriptyline was associated with more delta-wave production and higher delta-wave density in the first non-REM (NREM) period relative to the second. Nortriptyline levels were positively but weakly related to all-night delta-wave production during maintenance (accounting for 6.6% of the variance in delta-wave counts). Total phasic REM activity increased 100% under chronic nortriptyline relative to placebo, with a robust increase in the rate of REM activity generation across the night. Effective long-term pharmacotherapy of recurrent major depression is associated with enhancement in the rate of delta-wave production in the first NREM period (i.e., delta sleep ratio) and of REM activity throughout the night.

Differences over the life span in daily life-style regularity

A diary-based instrument-the Social Rhythm Metric (SRM)-was used to assess the level of stability of daily social and behavioral rhythms in a group of 239 healthy subjects (112 male, 127 female) ranging in age from 20 to 89 years. Each subject completed the instrument for two consecutive weeks, which were averaged to yield one measure (SRM score) of life-style regularity [range 0 (least regular) to 7 (most regular)] and another of activity level index (ALI), corresponding to the number of (diary listed) activities done per week (max. = 119). SRM score increased reliably with age group at an average rate of 0.018 units per year. ALI showed an "inverted U"-shaped function with a maximum at about 50 years. SRM changes appeared not to be related to demographic differences between the age groups, although ALI differences may have been so related. No main effects or interactions were found with gender. Life-style regularity appears to increase over the life span in response to both biological and psychosocial changes and may represent an adaptation to age-related changes in the circadian system's sensitivity to entraining agents. Regular behavioral rhythms may be conducive to continued good health and well-being.

Sleep in the wake of complicated grief symptoms: an exploratory study

Our aim was to explore the concept that the symptoms of complicated grief may be a form of posttraumatic distress, rather than depression, and thus may have different effects on sleep. Sixty-five recently bereaved elders with varying levels of symptoms of complicated grief and depression were stratified by high versus low levels of symptoms; a two-way analysis of variance examined main effects of level of complicated grief symptoms and depressive symptoms on selected sleep measures, as well as interactions. Complicated grief symptoms were independently associated with mild subjective sleep impairment but showed no main effects on electroencephalographic (EEG) sleep measures. In a multiple regression analysis, complicated grief symptoms interacted with depressive symptoms to increase REM sleep percent. Thus, it appears that complicated grief symptoms do not entail the changes of EEG sleep physiology seen in depression, with the possible exception of an interaction with coexisting depression to enhance REM sleep percent.

Longitudinal changes in diary- and laboratory-based sleep measures in healthy "old old" and "young old" subjects: a three-year follow-up

We report a longitudinal study of diary- and laboratory-based sleep measures in 50 healthy elderly subjects followed prospectively over a 3-year interval. Our hypothesis was that "old old" subjects (aged 75 to 87; n = 27) would show decline over time in measures of sleep quality, continuity, and depth, whereas "young old" subjects (aged 61 to 74; n = 23) were expected to show stability of outcome measures. Using analysis of variance-based planned contrast procedures, we found that this hypothesis was strongly supported for subjective sleep quality and laboratory measures of sleep latency, sleep efficiency, wakefulness after sleep onset, and slow-wave sleep percent. These changes were accompanied by increased napping in the old old. However, there was no change of habitual time in bed (total time or temporal placement of nighttime sleep), daily social rhythms, or sleep apnea. Change in medical burden scores did not correlate significantly with change in sleep efficiency or other outcome variables in the old old. Intervention designed to slow age-dependent decreases in sleep quality, continuity, and depth is discussed. The current results are representative of healthy elderly; sleep would probably deteriorate earlier and more quickly in elderly with more serious health problems and heavier medication use.

Social rhythm stability following late-life spousal bereavement: associations with depression and sleep impairment

The aim of this study was to investigate changes in social rhythm stability and sleep in spousally bereaved subjects (n = 94) and in nonbereaved elderly control subjects (n = 45). Social rhythm stability and activity level were measured with a diary-like instrument, the Social Rhythm Metric (SRM). We observed that spousal bereavement, per se, was not associated with a lower social rhythm stability or activity level except in the presence of a major depressive episode. We also observed an inverse correlation between severity of depression and social rhythm stability, and a positive correlation between depression and both subjective and objective measures of sleep impairment. Higher social rhythm stability was correlated with better sleep in subjects with high activity levels, but not in subjects with low activity levels. Longitudinal data, including pre-bereavement assessment of social rhythm stability, are necessary to ascertain directional effects, i.e., whether loss of spouse occasions disruption of social rhythms or whether such disruption precedes sleep impairment and depression.

Longitudinal effects of nortriptyline on EEG sleep and the likelihood of recurrence in elderly depressed patients

Our objectives were to determine the effects of nortriptyline and placebo on subjective and EEG sleep measures over 1 year of maintenance therapy in elderly depressed patients and to determine the relationship of such effects to recurrence in nortriptyline or placebo-treated patients during maintenance therapy. EEG and subjective sleep assessments were conducted before and during a maintenance therapy study of patients suffering from major depression. During acute treatment all patients received nortriptyline plus interpersonal psychotherapy (IPT). During maintenance treatment patients were randomly assigned to double-blind treatment in one of four cells: nortriptyline with IPT; nortriptyline with medication clinic (no IPT); placebo with IPT; or placebo with medication clinic. Sleep evaluations were conducted at one point before treatment, one point following remission during continuation nortriptyline/IPT treatment, and at three time points after random assignment to maintenance treatment. The setting was the sleep laboratory of the outpatient depression treatment clinic, and subjects were a convenience sample of media-recruited and clinically referred elderly outpatient depressed patients (n = 72). Complete sleep analyses were conducted for 21 nortriptyline- and 10 placebo-treated patients throughout 1 year of maintenance treatment. The main outcome measures were subjective and EEG sleep measures and the recurrence of major depression. Our results show that nortriptyline acutely and persistently decreased REM sleep, increased phasic REM activity, decreased sleep apnea, and had no effect on periodic limb movements during sleep. Recurrence on maintenance nortriptyline was associated with lower phasic REM activity during early continuation therapy, but EEG sleep measures did not predict recurrence during placebo maintenance therapy. Patients treated with nortriptyline had a lower recurrence rate than those treated with placebo. Better subjective sleep quality and maintenance IPT were associated with a lower rate of recurrence regardless of nortriptyline treatment. It seems that nortriptyline has persistent effects on REM sleep and sleep apnea in elderly depressed patients. Maintenance nortriptyline, maintenance IPT, good subjective sleep quality, and high-phasic REM activity are associated with a reduced likelihood of the recurrence of depression during maintenance therapy.

Electroencephalographic sleep profiles during depression. Effects of episode duration and other clinical and psychosocial factors in older adults

BACKGROUND

Limited evidence suggests that polysomnographic alterations may be more prominent early in a depressive episode. Whether the effects of episode duration extend beyond middle age and appear in late-life depression as well has important implications for treatment decisions and for understanding depressive illness across the life span. Furthermore, the impact of episode duration on sleep has not been examined in the context of other factors related to clinical history and psychosocial status.

METHODS

Eighty-three persons aged 60 years or older with recurrent depression were studied: 34 had been depressed for 2 to 16 weeks and 49 for longer periods. An age- and gender-matched group of 48 persons with no history of major depression served as controls. Initial univariate analyses examined duration effects on electroencephalographic (EEG) sleep measurements. Multivariate analyses considered the combined effects of episode duration, clinical variables, and psychosocial variables on EEG sleep profile.

RESULTS

Episode duration was strongly associated with sleep continuity, architecture, and rapid eye movement: subjects who were earlier in their depressive episodes had their sleep impaired more than those later in their episodes, who, in turn, were more impaired than controls. Moreover, clinical characteristics of subjects' depressive illness, demographic variables, and psychosocial stressors and supports had unique effects on the EEG sleep profile.

CONCLUSION

Episode duration appears to be a potent factor to consider when evaluating sleep during depression. The additional contribution of clinical and psychosocial characteristics to the prediction of the EEG sleep profile demonstrates the importance of incorporating these variables into models of the psychobiologic characteristics of depression. The results are relevant to the timing and focus of therapeutic interventions.

A longitudinal study of laboratory- and diary-based sleep measures in healthy "old old" and "young old" volunteers

The major aim of this study was to examine laboratory- and diary-based measures of sleep in a group of healthy ("successfully aging") "old old" subjects (> or = 75 years of age), as contrasted with a group of "young old" subjects (60-74 years of age), who were followed longitudinally for 2 years. We hypothesized that sleep would deteriorate to a greater extent over time among the old old subjects than among the young old. The study group consisted of 50 elders (21 male, 29 female; 23 old old, 27 young old), each studied at baseline and then again at 1- and 2-year follow-up. Analysis of variance was used to determine main effects of age group, gender and time on key sleep measures. Most measures were found to be remarkably stable over time. However, some decay was detected in sleep efficiency among the old old, but not among the young old. In a multiple regression model for the cohort as a whole, age, cognitive status and medical burden at baseline predicted subsequent declines in sleep efficiency over the 2-year period. To our knowledge, this is the first longitudinal data set on sleep in the healthy old old.

Sleep in bereavement-related depression during and after pharmacotherapy with nortriptyline

Our objective was to assess the effects of nortriptyline on electroencephalographic sleep and subjective sleep quality in spousally bereaved, depressed elders. Ten elderly volunteers with bereavement-related major depression had electroencephalographic sleep studies while depressed, after remission of depressive symptoms while still taking nortriptyline, and after nortriptyline discontinuation. Changes in sleep measures over time were compared both within bereaved subjects and with age- and sex-matched healthy controls. Remission of depressive symptoms while still on nortriptyline was associated with improvements in sleep quality (P < .002), rapid eye movement (REM) percent (P < .02), REM latency (P < .05), REM density (P < .05), and delta sleep ratio (P < .05). After discontinuation of nortriptyline, REM percent, REM latency, and delta ratio reverted to pretreatment levels, while sleep efficiency and sleep quality continued to show improvement coincident with sustained clinical remission. These data suggest that nortriptyline may be clinically useful in treating the sleep disturbance of elders with bereavement-related depression and that a double-blind, placebo-controlled, randomized clinical trial is warranted.

Psychosocial correlates and sequelae of electroencephalographic sleep in healthy elders

This research examines longitudinal data on psychosocial status and polysomnographic sleep collected annually from 57 healthy, community-residing elders aged 61-89. Cluster analysis of variables reflecting sleep continuity and architecture at the baseline assessment was used to identify three groups of elders: those whose sleep was either (a) superior to all remaining respondents across a variety of measures, (b) marred only by significantly reduced sleep efficiency relative to other respondents, or (c) poorer than all other respondents in multiple areas. Cross-validation procedures suggested that the three-group cluster solution was stable and replicable over persons and over time. Subsequent multivariate analyses indicated that recent life events, as well as psychosocial stability and support variables at baseline, distinguished between the sleep pattern groups. Moreover, sleep pattern group membership itself predicted subjects' subsequent sleep characteristics and psychosocial status at follow-up. Implications of these results for conceptualizing psychosocial factors that affect, and are ultimately affected by, sleep disturbances in late life are discussed.

Sleep after spousal bereavement: a study of recovery from stress

AIM

In this study, we compared repeated measures of electroencephalographic (EEG) sleep and subjective sleep quality in nondepressed, spousally bereaved elders and a healthy control group, in order to search for possible psychobiological correlates of bereavement not confounded by concurrent major depression.

METHOD

Laboratory-based EEG sleep studies and measures of subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]) were repeated at 3, 6, 11, 18, and 23 months after spousal bereavement in a study group of 27 elderly volunteers. Data were compared with similar measures from a control group of 27 nonbereaved subjects recorded on three occasions 1 year apart. Repeated-measures analysis of variance (ANOVA), using age as a covariate, examined effects due to time on selected variables in the bereaved group, as well as effects due to group, time, and group-by-time interactions in the experimental and control subjects.

RESULTS

Bereaved and control groups showed consistent differences over time in the phasic measures of rapid eye movement (REM) sleep (higher in bereaved subjects during the first and third REM sleep periods), but were similar on all other EEG sleep measures over the 2 years of observation. The bereaved showed a small decline in the percentage of slow-wave sleep over 2 years, but measures of sleep efficiency, REM latency, and delta sleep ratio were stable and did not differ from values seen in control subjects. Bereaved and control subjects were also similar on subjective sleep quality.

CONCLUSION

During successful adaptation to the loss of a spouse, and in the absence of major depression, spousal bereavement is associated with elevation in the phasic measures of REM sleep but does not appear to be associated with other physiologic sleep changes typical of major depression when studied at 3 to 23 months after the event. Although this observation does not preclude the possibility of significant sleep disturbance nearer the time of the event, it suggests that preservation of normal sleep following a major negative life event may be an important correlate of the resilience seen in successful aging. The elevation in REM density may provide a psychobiological correlate of bereavement not confounded by concurrent major depression.

Symposium: Normal and abnormal REM sleep regulation: REM sleep in successful, usual, and pathological aging: the Pittsburgh experience 1980-1993

Successful psychological and physical adaptation in late life correlates with preservation of sleep quality and physiological integrity of nocturnal EEG sleep measures. Failure to adapt is associated with loss of sleep continuity, alterations in the temporal distribution of delta wave activity, and by either a relative increase in REM sleep (e.g. in mood disorders) or a decrease in REM sleep (e.g. neurodegenerative disorders). Maintenance of sleep (particularly REM sleep) into late life may not be just a correlate, but also possibly a mechanism, of successful aging and thus necessary to the long-term maintenance of vitality and engagement in life.

Peripheral thermal responsivity to facial cooling during sleep

A recently developed technique for examining thermal sensitivity during sleep was used to assess whether skin and core temperature responses to thermal stimulation were altered by sleep state. The technique was designed to probe thermal responsivity without altering core body temperature or inducing awakening. Twenty-seven young men and women were studied during a sleep deprivation night and a sleep night three nights later. Cold water stimulation of the face alternated with an equal period of rewarming across a 40-min cycle throughout the night. Skin temperature from the finger and rectal temperature were continuously assessed. Sleep continuity and architecture were largely uninfluenced by the thermal stimulation. Finger skin temperature decreased during cold facial stimulation in both sleep and waking states. Skin temperature changes during sleep were approximately one-fifth the magnitude of those during waking. Core temperature was minimally influenced. REM sleep was associated with a greater amplitude decrease in finger temperature than was non-REM (NREM) sleep. The results support the utility of the technique as a probe of thermal responsivity during sleep and suggest a reduction of thermal responsivity during sleep and, more tentatively, an altered responsivity during REM versus NREM sleep.

Age and sleep modify finger temperature responses to facial cooling

BACKGROUND

The increased incidence of hypothermia with age suggests that healthy 80-year-olds might show impaired responsivity to transient, localized thermal stimulation. Such a deficit might be particularly clear during sleep, when behavioral thermoregulation is less likely.

METHODS

We examined finger temperature cooling in response to local cooling of the face--a response presumed to be centrally mediated. Nineteen healthy 80-year-olds (12 female) and twenty-seven 20-year-olds (10 female) were exposed to repetitive 20-minute cooling and rewarming cycles across a night of sleep deprivation and a night of sleep occurring three nights later. We sought to determine whether thermal responsivity was altered by age and sleep, but by design avoided inducing core temperature hypothermia.

RESULTS

In response to facial cooling during sleep deprivation, finger temperature decreased significantly more in the young than in old. This suggested relatively greater heat retention in the young. During non-REM sleep the thermal responsivity of both groups decreased and age-related differences were no longer present. Changes in core temperature induced by the stimulation were minimal.

CONCLUSIONS

The results suggest that the capability of retaining heat via peripheral vasoconstriction while awake decreases with age. Despite this vulnerability, responsivity during non-REM sleep as well as average core temperature were comparable between age groups.

Electroencephalographic sleep in recently remitted, elderly depressed patients in double-blind placebo-maintenance therapy

The aim of this double-blind placebo-controlled study was to assess the effects of clinical state on electroencephalographic (EEG) sleep measures in elderly patients with recurrent major depression. We hypothesized that rapid-eye movement (REM) latency and delta sleep ratio would remain stable between actively depressed and remitted states (i.e., show state independence), and measures of sleep continuity would improve with remission (i.e., show state dependence). Fifteen elderly outpatients (mean age 65.3 years) had sleep evaluations while ill and after remission, an average of 38 weeks later. All patients were in a double-blind placebo-maintenance condition at the time of follow-up studies. The major findings were: 1) no significant change in either REM latency or delta sleep ratio; 2) reduction in early morning awakening; and 3) improvement in subjective sleep quality despite the stability of most polysomnographic measures. We conclude that REM latency and delta sleep ratio are state-independent in patients with late-life depression, and that early morning awakening and sleep quality improve with remission of symptoms. These findings suggest that EEG sleep changes may have significance for understanding the longitudinal course of depression in late life.

Sleep-disordered breathing in healthy and spousally bereaved elderly: a one-year follow-up study

This study examined the progression of sleep-disordered breathing (SDB) over 1 year in two samples of elderly subjects: 45 healthy controls (20 men; 25 women mean age 74.8 years) and 27 recently spousally bereaved elders (9 men; 18 women, mean age 69.7 years). Although controls and bereaved subjects did not differ in the proportions with SDB, both groups showed a rise in the proportion of subjects with apnea hypopnea index > or = 5 and > or = 10 at 1-year follow-up and a small but statistically significant worsening in average maximum desaturation. The severity of SDB did not correlate with medical burden or with other clinical variables, such as severity of depressive symptoms. In summary, SDB increased longitudinally in both samples. This finding may have health implications for the aging population although at this time the implications are unclear.

Sleep in spousally bereaved elders with subsyndromal depressive symptoms

Spousal bereavement in late life frequently leads to major depression. However, many people suffer from "minor" depressive symptoms that entail considerable suffering even in the absence of syndromal major depression. We describe longitudinal electroencephalographic (EEG) sleep and clinical evaluations in 14 elderly, recently spousally bereaved subjects who were experiencing subsyndromal depressive symptoms. While subjects did not meet diagnostic criteria for syndromal major depression, they did have mildly elevated scores on the Hamilton Rating Scale for Depression (mean = 10.6, range = 8-16) at the time of initial sleep studies (T1), which were carried out, on average, 5.5 months after loss of the spouse. Entry into the study was limited to volunteers who did not have a personal history of major depression or psychiatric disorder. Twelve subjects underwent followup clinical and EEG sleep evaluations (T2), 9.9 months after spousal loss. Fifty percent continued to show depressive symptoms at 6-month followup. Test-retest comparisons of sleep and clinical measures were made with a group of sex- and age-matched control subjects who were neither bereaved nor depressed. EEG sleep measures did not significantly correlate with time from loss of spouse, severity of depressive symptoms, or subjective sleep quality. Analysis of variance with repeated measures detected a significant group X time interaction effect for delta sleep ratio (decreasing in controls but increasing in the bereaved).

Daytime sleepiness and performance among healthy 80 and 20 year olds

This study investigated the relationship of daytime sleepiness and performance on a vigilance test in a sample of 10 healthy men and 13 women in their 80s (mean age 83.0 +/- 3.1 years) and 18 men and 12 women in their 20s (25.0 +/- 3.1). We hypothesized that "successfully" aged healthy individuals would have more daytime sleepiness with differentially greater decrements in performance than a younger comparison group. Daytime sleepiness was measured physiologically by the Multiple Sleep Latency Test (MSLT) and through self-report by the Stanford Sleepiness Scale (SSS). Morning and evening performance was measured with the Mackworth Clock Test of vigilance. The major findings were the absence of correlation between either MSLT or SSS daytime sleepiness with performance measures, no difference in daytime sleepiness between the old and young groups and performance decrements among the healthy elderly on all parameters. Results suggest that the modest decrements in performance among the elderly cannot be attributed to daytime sleepiness.

Electroencephalographic sleep in spousal bereavement and bereavement-related depression of late life

Although spousal bereavement in late life is common and frequently leads to major depression, the boundary between bereavement without a depressive syndrome and bereavement-related depression has been insufficiently studied from a physiological perspective. Because other forms of depression are associated with physiological changes, including sleep, we have attempted to clarify the relationship of bereavement and bereavement-related depression by investigating electroencephalographic (EEG) sleep in 31 elderly volunteers with recent spousal bereavement, stratified by the presence (n = 15) or the absence (n = 16) of major depression (Research Diagnostic Criteria). Entry into the study was limited to volunteers without a personal history of psychiatric disorder. As hypothesized, bereaved subjects with major depression had significantly lower sleep efficiency, more early morning awakening, shorter rapid eye movement (REM) latency, greater REM sleep percent, and lower rates of delta wave generation in the first nonREM (NREM) period, compared with bereaved subjects without depression. Furthermore, the sleep of bereaved subjects with single-episode major depression resembled that of elderly patients with recurrent unipolar major depression (n = 15) on measures noted above. Sleep in bereavement without depression was similar to that of 15 healthy control subjects (neither bereaved nor depressed). These findings suggest that the current DSM-III-R concept of uncomplicated bereavement is not confirmed, as the sleep patterns of subjects who develop a depressive syndrome in the context of bereavement, many of whom might be considered to have "uncomplicated bereavement" by DSM-III-R standards, are identical to sleep patterns found in major depressive episodes. To our knowledge, this is the first study of EEG sleep in spousal bereavement with and without major depression.

Rapid eye movement sleep deprivation in elderly patients with concurrent symptoms of depression and dementia

Rapid eye movement (REM) sleep measures distinguish elderly patients with depression from those with dementia. The authors used a 2-night REM sleep deprivation (RSD) protocol to characterize patients with mixed symptoms of depression and dementia in comparison with patients with "pure" depression or dementia and healthy controls. Mixed-symptom patients resembled dementia patients in baseline sleep measures, but their large change in phasic REM activity following RSD suggests neurobiological similarities to depression. Mixed-symptom patients with stable cognitive impairment had greater REM sleep rebound than those with a more progressive dementing course. These results are consistent with previous neuropathological and neurochemical data.

Daytime sleepiness in the healthy "old old": a comparison with young adults

OBJECTIVE

To determine if excessive daytime sleepiness is an inevitable consequence of aging.

METHODS

Daytime sleepiness was measured using Multiple Sleep Latency Tests (MSLT's) before and after a night of total sleep deprivation in a sample of 22 healthy men and women in their eighties and 29 men and women in their twenties.

RESULTS

Young adults were somewhat sleepier than elders, as measured by rapidity of sleep onset during daytime nap recordings using the MSLT, and showed a higher incidence of REM sleep during naps. However, recovery from the effects of acute sleep loss was slower in the elderly, judging from the presence of more daytime sleepiness 2 days after a night of total sleep deprivation. Such persistent sleepiness was absent in the young adult control group.

CONCLUSIONS

Healthy persons in late old age may have a level of daytime sleepiness no greater than, and perhaps even less than, that seen in healthy young adults.

Circadian characteristics of healthy 80-year-olds and their relationship to objectively recorded sleep

Thirty-four healthy older adults (self-described "good sleepers") in their ninth decade of life (16m/18f, mean age 83.1) were compared to 30 young controls in their third decade (21m/9f, mean age 25.5) with regard to: (a) circadian and personality characteristics as measured by the Horne-Ostberg Morningness Questionnaire (HOM), Circadian Type Questionnaire (CTQ) and Eysenck Personality Inventory (EPI); (b) measures of habitual bedtime, waketime, and time in bed from a 2-week sleep diary; and (c) polysomnographic measures from a (post-adaptation) night of sleep recording in the laboratory. In almost all laboratory measures the older group slept poorly compared with the young, acquiring about one hour less total recorded sleep. The older group showed earlier habitual time of waking than the young, and showed higher (more "morning-type") scores on test instruments (HOM, CTQ-M) designed to assess morning-evening orientation. They also showed a lack of flexibility in sleep patterns (higher CTQ-Rs score) and less intersubject and intrasubject variability in habitual sleep timing compared to the young. Older subjects' morningness test scores were significantly associated with objectively measured sleep durations, with a tendency toward "morning-type" circadian orientation being associated with longer sleep.

Sleep in late-life recurrent depression. Changes during early continuation therapy with nortriptyline

The sleep of thirty elderly patients with recurrent unipolar depression was examined at baseline (before acute treatment of the index episode) and again in a state of symptomatic remission with nortriptyline (mean steady-state level: 82.1 ng/ml). Continuation therapy with nortriptyline was associated with improvement of polysomnographic sleep maintenance (mainly in the third and fourth sleep cycles, to a level similar to that of controls), prolongation of rapid-eye-movement (REM) sleep latency (exceeding that of controls), and potentiation of slow-wave activity during the first non-REM (NREM) sleep period. Clinical improvement, as measured by the Hamilton Depression Rating Scale, was significantly associated with shift of delta activity toward sleep onset (p less than 0.002), prolongation of REM sleep latency (p less than 0.0001), and improvement in sleep maintenance (p less than 0.0002). Multiple regression analysis showed that the single best correlate of clinical change was prolongation of REM sleep latency (i.e., prolongation of first NREM period). Perceived sleep quality improved significantly during early continuation therapy with nortriptyline, but not to the level reported by a group of 30 age- and sex-matched healthy controls. The findings are consistent with the concept that anti-depressant drug efficacy may depend upon strengthening of the homeostatic regulation of sleep and upon changes in the REM-sleep regulation.

Quantification of subjective sleep quality in healthy elderly men and women using the Pittsburgh Sleep Quality Index (PSQI)

Subjective sleep quality deteriorates with aging, but the extent to which this is a product of age itself, as opposed to the medical or psychiatric problems associated with aging, has not been carefully studied. To investigate this issue, we examined the subjective sleep quality of 44 healthy subjects over 80 years of age (20 men, 24 women), and 35 healthy subjects [corrected] between the ages of 20 and 30 (23 men, 12 women) using the Pittsburgh Sleep Quality Index (PSQI). All subjects underwent rigorous medical and psychiatric evaluations to verify that they were in excellent physical and psychological health. Significant age effects were noted for the global PSQI score and several PSQI component scores, but overall sleep quality for the majority (68.1%) of 80-yr-olds fell within a categorically defined range for "good" sleepers. Measures of habitual sleep quality did not correlate strongly with most polysomnographic sleep measures, number of medications used or circadian measures in elderly subjects. These results show that subjective sleep quality does deteriorate in the healthy elderly, but not to the level seen in patients with sleep disorders. Extremely healthy elderly subjects appear to adapt in their perception of objectively disturbed sleep.

Acute open-trial nortriptyline therapy of bereavement-related depression in late life

BACKGROUND

The aim of this study was to generate preliminary data on the clinical efficacy of nortriptyline in bereavement-related depression in late life.

METHODS

Data are presented on 13 patients (5 men, 8 women), ranging in age from 61 to 78 years (mean = 71.1). Mean time from spousal loss to the beginning of treatment was 11.9 months (range 2-25). Subjects were required to meet Research Diagnostic Criteria for syndromal current major depression and to have a stable Hamilton Rating Scale for Depression (HAM-D) score of greater than or equal to 15. Ten of the 13 volunteers were experiencing their first lifetime episode of major depression. Patients were treated with nortriptyline (mean dose = 49.2 mg/day; mean steady-state level = 68.1 ng/mL). Ratings performed at base-line and weekly during therapy were used to assess symptomatology, intensity of grief, level of functioning, social support, physical impairment, and medication side effects.

RESULTS

Pretreatment HAM-D ratings average 22.1 +/- 3.6; posttreatment, 7.2 +/- 2.8, representing a 67.9% decrease. All other rating scales showed significant clinical improvement, except the Texas Revised Inventory of Grief (a measure of grief intensity) (pretreatment, 51.4 +/- 7.3; posttreatment, 46.6 +/- 6.9, only a 9.3% decrease).

CONCLUSIONS

These results suggest that nortriptyline is associated with significant symptomatic improvement in all areas of bereavement-related depression except continued intensity of grief after a median treatment interval of 6.4 weeks. This study indicates the need for a controlled clinical trial to determine the placebo response rate, the relapse rate after discontinuation of medication, and the value of combination therapy (using both pharmacotherapy and psychotherapy).

Electroencephalographic sleep in the healthy "old old": a comparison with the "young old" in visually scored and automated measures

This report extends the normative study of sleep into healthy 80-year-olds and compares them with healthy 70- and 60-year-olds. We observed stability of sleep efficiency and rapid eye movement sleep across three decades of late life, but a slight decline of slow-wave sleep in the 80-year-olds (decreased total delta wave counts). Women showed better preservation of slow-wave sleep than men. Automated EEG period analysis of this phenomenon demonstrated higher rates of delta wave production in the first NREM sleep period of women compared to that of men, a finding associated with longer REM sleep latencies in women. Unexpectedly, 80-year-old women showed decay in sleep maintenance, while 80-year-old men demonstrated stability of sleep maintenance, relative to their respective 60- and 70-year-old counterparts. Implications for the understanding of sleep and its regulation in health and aging are discussed.

Rapid eye movement sleep deprivation as a probe in elderly subjects

The effects of a 2-night rapid eye movement (REM) sleep deprivation (RSD) procedure on electroencephalographic sleep and mood were examined in 15 healthy elderly control subjects, 14 elderly patients with endogenous depression, and 15 patients with primary degenerative dementia. Compared with control subjects, both patient groups maintained a higher amount of REM sleep time and REM activity during RSD. Unexpectedly, depressed patients showed little rebound in visually scored or automated REM sleep measures following RSD, and they showed stability of REM activity temporal distribution from baseline to recovery conditions. This contrasted with the rebound in REM sleep activity seen in control subjects, and the more modest increase in demented patients. The RSD was fairly specific, with some impact on delta sleep during the procedure but not during recovery sleep. Mood ratings were unaffected by RSD. These findings demonstrated a greater plasticity of REM sleep regulation in the healthy elderly control subjects and suggested a higher REM "pressure" with a "ceiling effect" in depressed patients. Patients with dementia appeared to have an impaired capacity to respond to the challenge of RSD.

Comparison of sleep-disordered breathing among healthy elderly in the seventh, eighth, and ninth decades of life

We investigated the prevalence of sleep-disordered breathing (SDB) in healthy 80 year-old subjects (n = 38) as compared with healthy 70-(n = 33) and 60-year-old subjects (n = 34). The apnea-hypopnea index (AHI) increased significantly across decades: 39.5% (15 of 38) of 80 year olds, 33.3% (11 of 33) of 70 year olds, and 2.9% (1 of 34) of 60 year olds had an AHI greater than or equal to 5 (chi 2 = 14.0, p less than 0.001). The prevalence of SDB as measured by a more stringent apnea index criterion of greater than or equal to 5 was 18.9% of those in their 80s, 12.1% in their 70s, and 0% in their 60s (chi 2 = 6.63, p less than 0.05). Significant gender differences were noted in the proportion of subjects with AHI greater than or equal to 10: 22.4% of men versus 5.4% of women (chi 2 = 4.25, p less than 0.05). These data suggest that SDB increases with advancing age even in the healthy elderly and may be more marked in healthy men than women.

Sleep stage physiology, mood, and vigilance responses to total sleep deprivation in healthy 80-year-olds and 20-year-olds

Little is known about sleep and the effects of total sleep loss in the 'old old' (i.e., 80-year-olds). We investigated sleep, mood, and performance responses to acute sleep deprivation in healthy 80-year-olds (n = 10) and 20-year-olds (n = 14). The protocol consisted of three nights of baseline sleep, one night of total sleep deprivation, and two nights of recovery sleep. Mood and vigilance were tested using visual analog scales and a Mackworth clock procedure in the morning and evening of each study day. Daytime sleepiness was measured by five naps on the days following the third and sixth nights. Old subjects had lower sleep efficiency and less delta sleep than young subjects. However, sleep continuity and delta sleep were enhanced in both groups on the first recovery night, indicating that sleep changes in old subjects are at least partially reversible by this procedure. Surprisingly, young subjects had shorter daytime sleep latencies than the old, suggesting a greater unmet sleep need in the former group. Mood and performance were disturbed by sleep loss in both groups, but to a greater extent among the young. This suggests that acute total sleep loss is a more disruptive procedure for the young than for the old.

Sleep, gender, and depression: an analysis of gender effects on the electroencephalographic sleep of 302 depressed outpatients

Gender-related differences in electroencephalographic (EEG) sleep were examined in 151 pairs of men and women with major depression, all outpatients, matched for age and severity of depression. Across five decades (age 21-69), depressed men had less slow-wave sleep than did depressed women. Gender differences were small with respect to visually scored measures of slow-wave sleep time and percent, but moderate for gender differences in automated measures of slow-wave density. The time constant of the polygraph preamplifier significantly affected both visually scored and automatically scored slow-wave sleep. Other measures such as REM sleep latency, first REM period duration, sleep efficiency, and early morning awakening, showed robust age effects, but no main effects for gender or gender-by-age interactions. Gender effects on slow-wave sleep and delta-wave counts in depression parallel gender effects seen in healthy aging. The possibility of occult alcohol use by depressed male outpatients cannot be definitely excluded as a partial explanation of the current findings. However, covarying for past alcohol abuse did not negate the statistical significance of the observed gender effects on slow-wave sleep and delta-wave density. The possibility of gender differences in slow-wave regulatory mechanisms is suggested, but similarity in temporal distribution of delta-wave density between the first and second non-rapid-eye-movement (NREM) periods does not support gender differences in slow-wave sleep regulation.

Sleep and depression in late life

Depression is one of the most serious and prevalent neuropsychiatric disorders of old age. Despite its prevalence, depression in the aged is frequently unrecognized or is misdiagnosed. This article reviews the existing knowledge of several sleep-related areas and discusses possible future studies into sleep as a prognostic indicator for recurrent and bereavement-related depressions in late life.

Clinical significance of sleep-disordered breathing in Alzheimer's disease. Preliminary data

In a study of 15 probable Alzheimer's patients and 12 healthy elderly control subjects, Alzheimer's patients had a significantly higher apnea index (patients versus controls, mean +/- SD: 6.3 +/- 6.6 vs 1.8 +/- 2.7, P less than .05) and greater maximal duration of apnea (patients versus controls, median: 50.0 vs 28.5 seconds, P less than .001), but no significant increase in oxyhemoglobin desaturation compared with controls. (The accepted normal threshold for abnormality is an apnea index more than 5.) Although three of seven psychometric tests (odd-even, category retrieval, face-hand test) showed diurnal effects on one or more of their subscores, with Alzheimer's patients having significantly poorer scores at the AM than at PM testing, overnight change scores in the psychometric tests were not significantly correlated with severity of sleep-disordered breathing. Further, only 18.1% of the disruptive (ie, requiring intervention) nocturnal behaviors of the Alzheimer's patients were temporally linked to sleep-disordered breathing. The current data suggest that sleep-disordered breathing in nonmedicated Alzheimer's patients is relatively mild and is not a predictor of either overnight mental status changes, of disruptive nocturnal behaviors, or of daytime behavioral fluctuations. Additional studies of more severely demented patients and possibly of sleeping pill effects would be useful in further evaluating the role of sleep apnea in Alzheimer behavioral changes.

Electroencephalographic sleep in late-life neuropsychiatric disorders

Late-life depression and dementia of the Alzheimer's type both have profound, although different, effects on electroencephalographic (EEG) sleep patterns. Thus, while depression is associated with REM sleep disinhibition and extreme sleep fragmentation (e.g., sleep onset REM periods and early morning awakenings), Alzheimer's disease is associated with deficits in the production of phasic activity during sleep (e.g., rapid eye movements and K-complexes) and with increased rates of sleep-disordered breathing. These differences have been shown to be reliable in large numbers of patients during the past five years and appear to extend to differences in sleep between depressive pseudodementia and dementia with secondary depression. Preliminary data also suggest that pretreatment sleep onset REM periods may be associated with enhanced vulnerability to recurrent depression. In summary, sleep physiological measures provide useful diagnostic and prognostic indexes in late-life neuropsychiatric disorders.

Predicting mortality in mixed depression and dementia using EEG sleep variables

The authors report a study of electroencephalographic (EEG) sleep predictors of two-year mortality in 26 elderly patients with mixed symptoms of depression and cognitive impairment. Patients who had died by two-year follow-up were characterized by significantly longer rapid eye movement (REM) sleep latencies at baseline, less robust REM sleep rebound following all-night sleep deprivation, and baseline apnea-hypopnea indexes greater than 3. Logistic regression analysis using the apnea-hypopnea index value and REM latency correctly predicted 77% of survivors and non-survivors. Survival time following initial measurements was significantly correlated with REM sleep time (r = 0.78, p less than .02) and duration of first REM sleep period (r = 0.75, p less than .02). The authors speculate that changes in these predictor variables may indicate impairment in the cholinergic control of cognitive function, REM sleep, and respiratory function.