Normal Aging Changes Research Articles

Electrophysiology of Alzheimer's disease.

The EEG changes of normal aging are briefly outlined followed by an overview of the alterations caused by dementing processes with special reference to Alzheimer's disease The EEG manufestations of the various types of dementia are compared and contrasted. The relationships between the EEG slowing found in the dementias, the cognitive changes and cortical atrophy as demonstrated by computed tomography scanning are reviewed. The diagnostic relevance of average evoked potential recordings to dementia is examined with special emphasis on the brain stem auditory evoked responses, cortical visual evoked potential and the P300 wave.

Cognitive decline in advanced age: Future directions for the psychometric differentiation of normal and pathological age changes in cognitive function

In the effort to delineate the cognitive changes that are associated with advanced age, it is necessary to discriminate not only between the cognitive abilities of the young and the aged, but also between the cognitive abilities of the demented and nondemented elderly. The identification of the qualitative characteristics of age‐dependent cognitive decline is made difficult by the obscurity of the latter distinction, which is in turn a consequence of the insidious nature of the dementing process (American Psychiatric Association, 1980). It is not particularly helpful to compare the cognitive profile of the normal elderly person with that of the more severely demented patient, because the global nature of the cognitive deterioration in the more advanced stages of senile dementia produces deficits on virtually any cognitive measure, and therefore adds little contrast to the qualitative description of age‐specific changes in cognitive function. The approach adopted in the present review was to examine the co...

Slow wave sleep in elderly depressed, demented, and healthy subjects.

The application of automated analysis in the measurement of sleep electroencephalogram delta activity allows a more precise temporal description of slow wave sleep changes in normal and pathological aging than do standard, all-night, slow wave sleep measures. Thus, with a baseline crossing technique, elderly depressives were shown to have a higher delta count per minute during the second NREM sleep period than did controls or demented subjects. This difference reflected greater activity per minute in the 2-3 Hz frequency band (75-200 microV).

Memory function and brain biochemistry in normal aging and in senile dementia.

One might argue that the decrease in the number of brain cells as a function of age could be the source of the functional age deficits in memory performance. However, this possibility seems less likely since the actual loss of neurons up to advanced age is relatively small. There are no good estimates of the loss of synapses. Golgi staining of cortical neurons would indicate that there is a loss with higher age. So far, however, the most convincing data of marked loss with age appear at the biochemical level. Most human data fail to demonstrate a decrease in cholinergic and serotonergic activity as a function of normal aging, although there is a loss of corresponding receptors. In AD/SDAT, however, there is a marked damage to these systems. Conceivably, acetylcholine may be providing informational rather than tone setting or balancing influence on memory function. This may explain the failure of cholinomimetic drugs to improve memory in AD/SDAT due to their inability to supply the informational properties of normal neuronal transmission. The catecholamines, noradrenaline and dopamine are both lost in normal aging and to a much higher degree in AD/SDAT. Animal data show that noradrenaline deficiency results in scattered attention. Such a pattern might also exist in the intact aged and through guidance by means of instructions, contextual cues, and a richer TBR information, the elderly are being forced to attend. This may promote and supersede the normal functions of the noradrenaline system by directions from external rather than internal influences, conceivably by potentiating the remaining noradrenaline neurons. The cortical motor areas are relatively spared from neuro-degenerative changes in normal aging and in AD/SDAT and this might provide a neuroanatomical basis for the elderly's and mildly to moderately demented patients' success in memory performance when motor action is involved. The role of dopamine in motor function and its stability with age in hippocampus may also provide a neurochemical basis for the preservation of memory when the subjects are allowed to act physically during encoding.

A Clinicopathologic Study of Four Cases of Primary Open-Angle Glaucoma Compared to Normal Eyes

Eight eyes obtained at autopsy from four patient who had chronic open-angle glaucoma were compared to eyes with normal aging changes. Three cases were characterized by early and pronounced abnormalities in the uveal portion of the drainage angle. The findings consisted of formation of an exaggerated scleral spur upon the scleral roll by accretion and compaction of the overlying uveal meshwork, hyalinization and atrophy of the adjacent ciliary muscle, and atrophy of the iris root. The fourth case showed widespread proliferation of endothelium into the lumen of Schlemm's canal. We concluded that the predominant histologic findings in eyes with open-angle glaucoma consists of an exaggeration of normal aging processes, ranging in a spectrum from excessive involvement of the uveal pathway to excessive involvement of the canal of Schlemm pathway.

Werner's syndrome: In vivo and in vitro characteristics as a model of aging

Three patients who suffered from Werner's syndrome were studied to help to elucidate differences from and/or analogies to both clinical symptoms and biochemical changes in normal aging. Our patients commonly manifested graying of hair, atrophy and hyperkeratosis of the skin, cataracts and hypogonadism. Such alterations would appear to be analogous to normal aging phenomena. However, the types of cataracts, degree of skin changes and growth retardation in Werner's syndrome differed from the normal aging phenomena. Studies of endocrine functions in our patients did not show definite evidence of generalized hypopituitarism and impaired function of hormone secretion. Resistance to hormones human cholionic gonadotropin (hCG), luteinizing hormone-releasing hormone (LH-RH) and insulin was observed, suggesting a possible alteration of a diversity of proteins which may affect hormone receptors. Immunologic aspects were also studied, since the genetically programmed failure of thymic function could play a major role in the pathogenesis of aging and age-related diseases. Our results in three patients did not indicate any definite immunologic abnormalities. Culture studies showed that skin fibroblasts in Werner's syndrome exhibited more decreased potentials of in vitro clonal growth and elongation of newly synthesizing DMA as phenotypic expressions than did normal skin cells. Yet, in Werner's syndrome, cells repaired DNA damage normally. The relationship of these findings to the basic genetic defect of Werner's syndrome remains unknown.

The normal fine structure and aging changes of the human zonular fibers

The normal zonular fibrils of the human eye do not differ from the fibrils of the zonula Zinnii of the rat. Furthermore, there is no difference between the single zonular fibrils and the fibrils of the vitreous body in rat and man. The average diameter of the human zonular fibrils is 109 A. They are transversely striated at intervals with a periodicity of 70–150 A. Over periods of mostly 400–440 a, but also of 500–640 A were observed. At a few places over periods similar to those of the long spacing-type packing were found. Like in the rat eye, the zonular fibrils of the human eye must be regarded as a special form of collagen. An indirect proof for the collageneous nature of the zonular fibrils is the occurence in advanced age of degenerative alterations which are exclusively observed in connective tissue (hyalinization, elastoid degeneration).

Normal age changes in the rat mandibular joint.

SYNOPSIS IN INTERLINGUA ALTERATIONES NORMAL DE INVETULATION IN LE ARTICULATION MANDIBULAR DEL RATTO.—Esseva studiate le normal crescentia e morphologia del articulation mandibular del ratto. Le articulationes studiate includeva specimens ab 15 differente gruppos de etate ab 1 die ad 2 annos. Le alterationes causate per le processos normal del invetulation es describite pro le areas principal del articulation, i.e., le fossa del articulation, le disco articular, e le condylo mandibular. Marcate alterationes esseva observate in le osso del fossa articular e del condylo. Alterationes de character plus subtil esseva notate in le disco articular. Le consta tation le plus remarcabile esseva le constantia del spissitate del cartilagine condylar post le cinquantesime die del vita.

THE RADIOLOGICAL SPECTRUM OF AGING AND EMPHYSEMATOUS LUNGS.

Emphysema of the lungs is becoming recognized as the most common condition to produce pulmonary disability in later life (37). Recently changing clinical and pathologic concepts (20, 24, 29, 30, 36) point up the need for re-evaluation of the classic criteria of radiologic interpretation. A variety of diagnostic methods, including history, physical examination, radiographic studies, and various pulmonary function tests are used in the appraisal of emphysematous patients. Limitations in the reliability of history and physical findings are considered elsewhere (31). Pulmonary function tests are valuable in assessing the degree of functional impairment (14), but in many instances are not as readily available as radiography. Accordingly, a study was performed to ascertain the radiologic features of emphysematous and normal aging subjects on plain films, the ability of competent observers to detect such changes, and the reliability of present criteria in differentiating aging and emphysematous patients. This work is one part of a continuing multi-disciplinary study of emphysema (1–6, 31). Emphysema is derived from the Greek word “emphysao” which means “inflate” or “blow up” (38). With the development of more precise knowledge of pulmonary pathology and physiology, the term pulmonary emphysema has come to refer to “obstructive lung disease” of a chronic nature (25). This is reflected in the recent definition by the American Thoracic Society (35): “Emphysema is an anatomic alteration of the lung characterized by an abnormal enlargement of the air spaces distal to the terminal non-respiratory bronchiole accompanied by destructive changes in the alveolar walls.” Hyperinflation (overinflation) is a general term which refers to overdistention of the lungs from any cause (35). Hyperinflation is characterized by enlargement and rounding of the thorax and compression and displacement of surrounding structures (5, 19,28). Although hyperinflation may be a manifestation of pulmonary emphysema, it may also be observed in normal subjects with a large vital capacity, as a manifestation of the normal aging process, and in asthma or any other condition producing airway obstruction. Physiologic aging changes, e.g., the barrel configuration of the chest, may suggest emphysema (Figs. 1 and 2) and yet be associated with no significant physiologic or pathologic alteration (18, 23, 28). These patients are sometimes reported on radiographic examination of the chest as having senile emphysema which, according to the current definition of emphysema, is a misnomer. Therefore, the extent to which normal aging changes could be differentiated radiographically from emphysema was considered. Methods and Materials The evaluation of radiographic signs and diagnosis reported here was based on the interpretation of radiographs of aging and emphysematous patients as practiced in the daily routine of physicians devoting full time to radiology.

INCIDENCE AND PROGNOSIS OF COXARTHROSIS.

To define radiographic criteria, the radiographs of all patients diagnosed with coxarthrosis during the year 1951 were reviewed. Structural or joint space changes, evident radiographically in one of every seven cases in 1951, persisted at the time of the review in 1962. In the remaining cases, the diagnosis had been based upon the presence of osteophytic changes alone. Only one of 86 such cases reviewed in 1962 had structural or joint space changes. Osteophytes had no clinical significance and did not progress to coxarthrosis. Osteophytes appear to be a part of normal age changes. The radiographic diagnosis of coxarthrosis must be based on the demonstration of structural or joint changes

Dental Anatomy and Histology of the Dog

SUMMARY The morphology of the teeth and the histological structure of the dental tissues of the dog are described. Reference is made to modifications associated with the specialized function of the dentition and to normal age changes observed.

Characteristics of Adults Basic to Education

THIS chapter summarizing characteristics of adults which are basic to education is based primarily on references that have appeared since 1944. It must necessarily eliminate major contributions that formed basis of knowledge of adult psychology. Since Thorndike's Adult Learning was published, considerable interest has been shown in psychological and medical adjustment of last half of life span. The past few years have seen two new journals devoted to field of the aged, aging and dying. Geriatrics (3) and Journal of Gerontology (26) from time to time included articles of psychological significance. The Journal of Gerontology included review articles as well as a fairly complete index to current periodical literature. Under Cowdry's able editorship, revised edition of Problems of Ageing (14) was published in 1942. Of particular interest to educators are Friedenwald's chapter on eye, Guild's on ear, Miles' on psychological aspects of aging, and Hamilton's on personality and psychosexual phenomena. Stieglitz's (68) The Second Forty Years is a very adequate summary of adult characteristics, especially from medical viewpoint. The recently revised edition of Geriatric Medicine (66) summarized medical aspects of aging, and also included an excellent chapter on mental changes in normal aging by Miles and Miles (51). This chapter surveyed age in its relation to sensory and motor activity, intelligence, learning, interest, personality, and productivity. Hunt and Cofer (32) integrated literature on psychological deficit. Altho these authors' orientation was with personality disorder, there was extensive reference to normal individuals. A very adequate bibliography accompanied discussion.