Neurological signs in the elderly

Cerebral white matter changes are associated with abnormalities on neurological examination in non-disabled elderly: the LADIS study

Cerebral white matter changes (WMC) are associated with motor, cognitive, mood, urinary disturbances, and disability, but little is known about the prevalence of neurological signs in patients with these brain lesions. We assessed the presence and occurrence of neurological abnormalities over a 3-year period and their possible associations with WMC in a cohort of initially non-disabled elderly subjects. Data from the multicenter Leukoaraiosis And DISability study were used. A standard neurological examination was performed at baseline and at each of the annual follow-up visits. A standard MRI scan was performed at baseline and after 3-years. WMC severity was graded as mild, moderate, or severe on the Fazekas scale, while the Rotterdam scale was used to assess progression. Infarcts and their occurrence were also assessed. Six hundred and thirty-nine non-disabled subjects were enrolled (mean age 74.1 ± 5.0, M/F: 288/351). Severe WMC at baseline were associated with gait and stance abnormalities, upper motor signs, and fingertap slowing. This effect was independent of age, sex, lacunar and non-lacunar infarcts. The occurrence of stance abnormalities, upper motor signs, primitive reflexes and fingertap slowing during the 3-year follow-up period was associated with both baseline WMC load and their progression. The occurrence of the same abnormalities plus extrapyramidal and primitive reflexes was associated with incident lacunar infarcts. In our cohort of non-disabled elders, severe WMC were associated with the presence and the occurrence of neurological signs, independently of other vascular brain lesions, confirming that these lesions have clinical relevance.

Neurological abnormalities and neurocognitive functions in healthy elder people: a structural equation modeling analysis

BACKGROUND/AIMS

Neurological abnormalities have been reported in normal aging population. However, most of them were limited to extrapyramidal signs and soft signs such as motor coordination and sensory integration have received much less attention. Very little is known about the relationship between neurological soft signs and neurocognitive function in healthy elder people. The current study aimed to examine the underlying relationships between neurological soft signs and neurocognition in a group of healthy elderly.

METHODS

One hundred and eighty healthy elderly participated in the current study. Neurological soft signs were evaluated with the subscales of Cambridge Neurological Inventory. A set of neurocognitive tests was also administered to all the participants. Structural equation modeling was adopted to examine the underlying relationship between neurological soft signs and neurocognition.

RESULTS

No significant differences were found between the male and female elder people in neurocognitive function performances and neurological soft signs. The model fitted well in the elderly and indicated the moderate associations between neurological soft signs and neurocognition, specifically verbal memory, visual memory and working memory.

CONCLUSIONS

The neurological soft signs are more or less statistically equivalent to capture the similar information done by conventional neurocognitive function tests in the elderly. The implication of these findings may serve as a potential neurological marker for the early detection of pathological aging diseases or related mental status such as mild cognitive impairment and Alzheimer's disease.

A Poisson-like model of sub-clinical signs from the examination of healthy aging subjects

BACKGROUND AND AIMS

Our studies of the standard neurological examination on 66 middle-aged (50-64 yrs) and elderly subjects (65-84 yrs) demonstrate that healthy elders have neurological deficits (or "signs") that are not associated with specific known neurological disease. The purpose of the current study is to describe this loss of neurological function in healthy aging subjects as seen through accumulated subclinical neurological signs present.

METHODS

Logistic regression is applied to the data on each of six signs. Parameters determined are used to describe the distribution of first occurrence times for each sign. The results are then used to construct a Poisson-like model that describes the accumulation in the number of signs present over time on average. This model is also used to simulate a longitudinal population to explore the variability in the number of signs present over time in an aging population.

RESULTS

As the rate of arrival of the signs is heterogeneous, as determined through logistic regression, and the number of signs detected is finite, the resulting distributions of the number of signs over time have a different nature than Poisson. Our results suggest that we can expect to see on average one neurological deficit in healthy people by the age of 62, and that the expected number of deficits increases linearly at the rate of 1 additional sign every 12 years over a wide age range (age 70-90). The distribution of the number of deficits over time is also described.

CONCLUSIONS

The linearity in the average rate at which signs appear in this population is somewhat of a surprise, in that an increasing (accelerating) rate might be anticipated. In addition to characterizing the neurological exam results in this group, we demonstrate a methodology that allows the comparison of groups and defines a rate of neurological aging.

The meaning of distal sensory loss and absent ankle reflexes in relation to age

CONTEXT

Polyneuropathy is a common disease and is more prevalent (at least 3 %) in elderly people. However, routine neurological examination of healthy elderly people may show distal sensory loss and absent tendon reflexes, which can obscure the distinction from polyneuropathy.

OBJECTIVE

To investigate the relation between age and the prevalence of distal sensory loss, absent tendon reflexes, or muscle weakness, and to ascertain above which age these neurological signs could be considered as normal in ageing.

DATA SOURCES

PubMed, Embase, the Cochrane Library, and Current Contents from 1960 until 2004. Reference lists of relevant studies were searched for additional studies, reviews or textbooks.

STUDY SELECTION

Studies reporting on neurological signs upon routine neurological examination in generally healthy adult persons were considered for inclusion. Two reviewers independently assessed study eligibility and performed study inclusion. Of 629 studies initially identified, 50 (8 %) met the inclusion criteria.

DATA EXTRACTION

Two reviewers independently performed data extraction and assessed study quality based on study design and the rigour by which confounding co-morbidity was excluded.

DATA SYNTHESIS

The 50 included studies comprised a total of 9,996 adult persons. Assuming heterogeneity between studies, the prevalence data from different studies were pooled for separate age groups with a random-effects model. In healthy persons older than 60 years the prevalence of absent vibration sense at the big toes (29 % [95 % CI 18 % to 38%]) or ankles (15 % [95 % CI 11 % to 20%]), and absent ankle reflexes (23 % [95 % CI 16 % to 30 %]) was increased.

CONCLUSIONS

Self-declared healthy adult persons younger than 60 years do not have neurological signs. After the age of 60 absent vibration sense at the big toes or ankles, and absent ankle reflexes are more prevalent, although the majority does not have these neurological signs. It seems more appropriate to apply different diagnostic criteria for polyneuropathy in adult persons younger and older than 60 years.

Lower limb function as predictor of falls and loss of mobility with social repercussions one year after discharge among elderly inpatients

BACKGROUND AND AIMS

Poor mobility of the lower limbs in community-dwelling elderly people is a predictor of functional decline in terms of disability, falls, nursing home admission, and death. However, its predictive value has not been studied in acute care hospital settings. The aims of this observational, prospective study were: 1) to assess the prognostic value of lower limb function; and 2) to compare the predictive value of three performance tests in elderly inpatients.

METHODS

We studied 144 patients aged 70 or older (60 men and 84 women, mean age 78.7 +/- 5.6 years), admitted consecutively to a general internal medicine ward. Before discharge, patients underwent multidimensional assessment, including static and dynamic equilibrium and gait, by the Performance-Oriented Mobility Assessment (POMA), Short Physical Performance Battery (SPPB), and Functional Reach (FR). One-year outcomes were falls, loss of mobility with social repercussions (inability to leave home, or need for nursing home care) and death.

RESULTS

In univariate analysis, poor results on any of the three tests were associated with an increased risk of falls, loss of mobility with social repercussions, and death. In multivariate analysis, age, two or more falls, and a low POMA score were predictive of future falls, whereas dependency in instrumental activities of daily living and a low SPPB score were predictive of loss of mobility with social repercussions. No multivariate model was superior to univariate ones in predicting death. No associations were found between other medical or geriatric characteristics and outcomes.

CONCLUSIONS

Lower limb mobility tests performed in an acute care hospital setting are predictive of future falls, inability to leave home, and/or need for nursing home care.

The clinical identification of peripheral neuropathy among older persons

OBJECTIVE

To identify simple clinical rules for the detection of a diffuse peripheral neuropathy among older outpatients.

DESIGN

Observational, blinded, controlled study.

SETTING

A tertiary-care electrodiagnostic laboratory and biomechanics laboratory.

PARTICIPANTS

One hundred research subjects, 68 with electrodiagnostic evidence of peripheral neuropathy, between the ages of 50 and 80 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASUREMENTS

One examiner, unaware of the results of electrodiagnostic testing, evaluated Achilles' and patellar reflexes, Romberg testing, semiquantified vibration, and position sense at the toe and ankle in all subjects, and unipedal stance time and the Michigan Diabetes Neuropathy Score in a subset of subjects.

RESULTS

Significant group differences were present in all clinical measures tested. Three signs, Achilles' reflex (absent despite facilitation), vibration (128Hz tuning fork perceived for <10s), and position sense (<8/10 1-cm trials) at the toe, were the best predictors of peripheral neuropathy on both univariate and logistic regression (pseudo R(2)=.744) analyses. The presence of 2 or 3 signs versus 0 or 1 sign identified peripheral neuropathy with sensitivity, specificity, and positive and negative predictive values of 94.1%, 84.4%, 92.8%, and 87.1%, respectively. Values were similar among subgroups of subjects with and without diabetes mellitus. When other clinicians applied the technique to 12 more subjects, excellent interrater reliability regarding the presence of peripheral neuropathy (kappa=.833) and good to excellent interrater reliability for each sign (kappa range,.667-1.00) were shown.

CONCLUSION

Among older persons, the presence of 2 or 3 of the 3 clinical signs strongly suggested electrodiagnostic evidence of a peripheral neuropathy, regardless of etiology. Age-related decline in peripheral nerve function need not be a barrier to the clinical recognition of a diffuse peripheral neuropathy among older persons.

Neurologic disorders of gait

Gait disorders are important because of their prevalence, particularly among the elderly, and the associated risk of falls and injury. Neural networks that organize locomotion and maintain balance are briefly reviewed. Gait disorders can be classified based on observational features or by etiology. Several common disorders are discussed in more detail. Recent progress includes use of botulinum toxin for spastic gait in cerebral palsy, neurosurgical treatment of Parkinson's disease, and newer rehabilitation approaches to gait and balance training.

Age differences in postural sway during volitional head movement

OBJECTIVE

To examine the role of a volitional self-paced head-turn movement on the postural sway characteristics of healthy young and elderly subjects.

DESIGN

Cross-sectional design.

SETTING

Motor control research laboratory.

SUBJECTS

Ten young adults and 10 elderly subjects.

MAIN OUTCOME MEASURES

Postural sway characteristics of each subject were examined using a Kistler force platform. Each subject was tested under four experimental conditions: (1) static postural sway with vision; (2) static postural sway without vision; (3) postural sway with vision and self-paced head-turn movement; and (4) postural sway with no vision and a self-paced head-turn movement. Subjects performed six 15-second trials in each experimental condition. Dependent variables analyzed on each trial were mean sway amplitude (in millimeters), sagittal sway standard deviation, lateral sway standard deviation, and frequency of sway (in hertz).

RESULTS

During the static conditions (e.g., no voluntary movement), the young subjects produced significantly less postural sway than the elderly in both the vision condition (sway amplitude in the young, 3.80 mm; in the elderly, 4.89 mm) and the no-vision condition (young, 5.44 mm; elderly, 5.95 mm). This increased sway was the result of greater lateral sway in the elderly for the vision condition (3.73 vs. 2.68 mm), and greater sagittal sway for the elderly in the no-vision condition (5.55 vs. 4.70 mm). There were no significant differences between the groups in the frequency of sway. When asked to initiate and complete the head-turn, elderly subjects significantly increased their mean sway amplitude and decreased their frequency of sway, whereas the young subjects did not significantly alter their postural sway profiles.

CONCLUSIONS

These results demonstrate different postural sway control strategies for young and elderly subjects when asked to perform volitional movements.

Aging and the basal ganglia

Age-related changes within the basal ganglia primarily affect the dopaminergic nigrostriatal pathway and related pigmented nuclei. These alterations resemble the pathologic changes of Parkinson's disease, but cell dropout is not as marked or uniquely selective in the aged brain. Histopathologic changes including interneuronal inclusion bodies are associated with aging, but the number and location of these suggest that this is a nonspecific phenomenon, not the harbinger of Parkinson's disease or other specific neuropathology. It appears that aging and Parkinson's disease result in similar brain cell degenerative processes, but the causes and specific triggering mechanisms for these changes are likely to be quite distinct.

Effects of Optic Flow on the Kinematics of Human Gait: A Comparison of Young and Older Adults

This experiment studied the effect of imposed optic flow on human locomotion. Six young and 6 older adults were exposed to various patterns of optic flow while walking in a moving hallway. Results showed few cases of impaired postural control (staggers, parachute reactions). No falls were recorded. Kinematic patterns of gait were altered when vision was absent or inconsistent optic flow was presented: Ninety two percent of the subjects' mean step velocity differed from their step velocities under normal vision. Compared with imposed central flow, peripheral optic flow was not dominant in inducing kinematic changes. Characteristic gait profiles were obtained, depending on flow direction. Global backward flow tended to slow down step velocity, whereas subjects' step velocity increased during conditions of forward flow. The results suggest that subjects attempted to match their own walking speed to the velocity of the moving visual scenes. It is concluded that in an uncluttered environment, imposed optic flow has a modulating rather than a destabilizing effect on human locomotion.

EMG study on the effect of ageing on the human masseteric jaw-jerk reflex

The effect of age on the masseteric jaw-jerk reflex was investigated in 22 young (11 males and 11 females with mean age 23.2 years) and 22 older dentate subjects (11 males and 11 females with mean age 61.3 years). Electromyographic (EMG) recordings were obtained, after chin taps, from the relaxed masseter muscle of the preferred chewing side, by use of a computerised recording and analysis system. With increasing age the occurrence of the reflex was reduced, the latency was increased, while the amplitude was decreased. Those findings are probably related to the general age related changes in the muscular tissue, the sense organs, the peripheral nerves and especially the central nervous system. Increased biological variance was also observed in the older subjects, as in most aspects of performance in the latent years. Furthermore, the effects of ageing were generally similar in men and women. The age-related decrement in the monosynaptic reflex response is indicative of a generalised decline in the motor performance of the stomatognathic system and the decreased ability of the older dental patient to easily adapt to any dramatic changes in the sensory input.

Reproducibility of the human masseteric jaw-jerk reflex in association with the menstrual cycle

The jaw jerk was elicited by chin taps in the relaxed masseter muscle of the preferred chewing side in five young females. Recordings were made during three randomized sessions and under standardized conditions: two sessions between the seventh and the 15th day of the female menstrual cycle and the third within the last 5 days of the cycle. Both latency and duration of the reflex were generally reproducible over time. Individual between-session variation was occasionally present, with a general tendency for lower values in the end-cycle session, but this did not affect the overall results. Systematic subject variation, such as central excitatory-state variance of the timing of the experiments, and possibly some other uncontrolled technical error, may have contributed to the observed variation.

The clinical diagnosis of sensory neuropathy in elderly people

Minor abnormalities in sensory perception are common in elderly people but the significance of these findings is uncertain. In order to define the most relevant clinical tests for the diagnosis of significant neuropathy in the elderly diabetic patient, quantified perception of vibration, temperature, pain, and light touch was assessed in 200 (100 hospitalized, 100 community) consecutive non-diabetic elderly subjects without apparent neurological disease, using an established scoring system. The changes in sensory perception were similar in the two groups and data were pooled for further analysis. Progressive loss of peripheral sensation was apparent with increasing age (neuropathy deficit score vs age: r = .04, p < 0.0001). Loss of vibration perception was particularly marked; deficit scores for vibration were significantly lower in the < 70 years age group than in all the older age groups (vibration score: < 70 years vs 80-84 years mean (95% CI) 0.89 (0.54) vs 3.02 (0.6), p < 0.0001). In contrast, perception of light touch and pain was relatively preserved in old age. Assessment of vibration perception is of limited value in elderly people since the distinction between 'normal ageing' and significant neuropathy is unclear. Perception of light touch and pain are likely to be the most reliable clinical indicators of significant neuropathy in an elderly diabetic population.

Anterior digastric muscle responses to sudden unloading of the mandibular elevator muscles in younger and older adults

The digastric motor responses in the unloading reflex were investigated in a sample of 10 younger and eight older dentate subjects. The occurrence of the pre-collapse digastric activity (PDA) and the reflex events (burst of activity) following the mandibular unloading (DB) were studied separately. PDA was nearly consistent in half of the subjects of both groups. DB was clearly identified in 60% of the younger subjects, but in 54.2% of the older subjects. The mean latency of DB found in the younger subjects was 32.4 +/- 9.5 ms but 34.5 +/- 8.8 ms in the older subjects. For the latencies found we can infer that they are related to polysynaptic pathways. Also a slight tendency for decreased frequency of occurrence and increased latencies of DB is observed in the older age group.

Differences in postural hypotension and ankle jerks in the elderly from two contrasting socio-economic levels

Subjects in low socio-economic strata in underdeveloped countries are subjected to considerable adverse influences which may enhance age-related changes in the nervous system. We therefore assessed the presence of ankle jerks and the degree of postural hypotension in two groups, one from the upper socio-economic level (58 subjects) and the other from the lower socio-economic level (56 subjects). All subjects were over 65 years of age. Only 6% had bilateral loss of ankle jerks, with no difference between the groups. Postural hypotension of 30 mmHg or greater was more frequent in the upper socio-economic group, nine out of 58 versus two out of 56 in the lower group. We conclude that there is no relationship in the elderly between social deprivation and certain markers of neurological dysfunction, such as the absence of ankle jerks and postural hypotension. The reasons for a greater frequency of postural hypotension in the higher socio-economic group are unclear.

Age-related changes in cerebrospinal fluid protein concentrations

The blood-brain barrier (BBB) has a key role in CSF homeostasis and preservation of normal neuronal function. There has been little investigation of changes in barrier function in elderly subjects without evidence of neurological disease. The ageing brain demonstrates increased vulnerability to a variety of insults, which may reflect a deterioration in barrier performance. Direct measurement of BBB function is difficult but the CSF/serum quotients of individual proteins is the most widely used parameter. The present study sought age related changes in the CSF/serum quotients of prealbumin, albumin, immunoglobulin G and alpha 2-macroglobulin in adults with no neurological deficit. A prospective study was established, and 107 subjects (aged 18-89 yrs) were recruited from patients undergoing spinal anaesthesia or diagnostic myelography. A weak but significant positive correlation was found between the CSF/serum quotients and age for all the proteins studied, but with the exception of alpha 2-macroglobulin, these changes probably reflect age related falls in serum protein concentrations found in this study. alpha 2-Macroglobulin appears to be a sensitive indicator of barrier function for large populations, suggesting a subtle decline of BBB integrity with increasing age. This may be a true age-related change or could reflect an increased incidence of subclinical disease in an ageing population.

Stride-dependent changes in gait of older people

Infrared computerized stroboscopic photometry was used to measure the kinematic profile of walking of 20 young adults and 20 neurologically healthy elderly people. Compared with the young adults, the elderly exhibited 17-20% reductions in the velocity of gait and length of stride. The elderly also exhibited comparable reductions in the maximum toe-floor clearance, arm swing, and rotations of the hips and knees, but these alterations in gait were attributable to the reduction in stride length, which may have non-neurological causes. The influence of reduced gait velocity and stride length on the other characteristics of walking must be considered when evaluating the pattern of walking in elderly people.

The elderly and their ankle jerks

The ankle jerks of 200 consecutive patients admitted to a geriatric department were assessed on the second or third hospital days by two independent observers. The test consisted of a "plantar" rather than Achilles tendon strike with a standard patellar hammer. 188 patients had ankle jerks. This finding is at variance with most previous reports on the subject. This difference may be due to, amongst other factors, the timing and method of testing.