Aging and vestibular system: specific tests and role of melatonin in cognitive involvement.

Balance disorders are frequent with aging. They are particularly important because they decrease social autonomy of the aged subjects and they often provoke falls. The cause is always multifactorial. There is evidence that aging affects multiple sensory inputs, as well as the muscoloskeletal system and central nervous system ability to perform sensorimotor integration. For the evaluation of decreased balance skills in elderly, a specific questionnaire has been prepared, in order to identify high risk of falling called falling risk inventory (FRI) questionnaire, and a complex psycho-sensory-motor test has been studied by means of posturography, in order to detect specific vestibular impairment. Regarding ethiopathogenesis of balance disorders in aged subjects, because the decline of behavioral and cognitive performances are due also to decline of biological rhythm control, the role of melatonin (the hormone regulating circadian rhythms, being strictly connected with cerebellar function, and it is well known that cerebellum acts in elderly both at motor and cognitive regulation. The goals of the present paper are: (i) To present a self-administered FRI questionnaire aimed at identifying possible causes of falls and quantifying falling risk in aged. (ii) To validate posturography as a specific test to investigate vestibular involvement in elderly in correlation with FRI. (iii) To present a complex behavioral test (NT) aimed at evaluating both spatial orientation and spatial memory in elderly, factors involved into the genesis of complex dizziness and unsteadiness. (iv) To evaluate the role of melatonin in cognitive involvement in dizzy, old subjects due to the functional correlations between circadian rhythms, cerebellum balance disturbances and cognitive disorders. General conclusions are: FRI correlates with falling risk. Posturography identifies specific vestibular impairments correlated to balance disorders and elderly falls. Spatial orientation is altered in about 40% of dizzy patients but no significant differences are revealed in melatonin rhythm. Spatial memory is highly altered only in subjects with inversion of circadian melatonin rhythm it is possible to hypothesize that the alteration of the normal circadian melatonin rhythm plays some role in the genesis of dizziness in a subpopulation of patients.

Postural characteristics of diabetic neuropathy.

OBJECTIVE: To explore the posturographic correlates of diabetic neuropathy by comparing the performances of three groups of diabetic patients (severe, moderate, and absent neuropathy) with those of normal subjects and four clinical control groups. RESEARCH DESIGN AND METHODS: Using the Interactive Balance System (Tetrax, Ramat Gan, Israel), based on the assessment of the interaction of vertical pressure fluctuations on four independent platforms, one for each heel and toe part, respectively, posturographic examinations were given to 28 diabetic patients (8 with severe, 12 with moderate, and 8 with no peripheral neuropathy), 30 normal control subjects, and a clinical control group of 52 patients (14 with stage II Parkinson's disease, 13 with brain damage, 7 with whiplash, and 19 with peripheral vestibular pathology). The following posturographic parameters were evaluated; 1) general stability; 2) Fourier analysis showing patterns of sway intensity within eight frequency bands between 0.1 and 3 Hz; 3) weight distribution; 4) synchronization of sway; and 5) performance patterns for eight positions, requiring closure of eyes and standing on an elastic surface, as well as left, right, back, and downward head turns. RESULTS: For positions with closed eyes, diabetic patients with severe and moderate neuropathy were significantly less stable than normal subjects and diabetic patients without neuropathy, but diabetic patients with severe and moderate neuropathy turned out to be as equally unstable as clinical control subjects. However, for sway intensity within the band of 0.5 to 1.00 Hz on positions with lateral head turn with occluded vision, neuropathic diabetic patients performed significantly worse than did both normal and clinical control subjects. The same posturographic parameter also differed significantly between normal subjects and diabetic patients without neuropathy. CONCLUSIONS: As reported in previous studies, general instability in diabetic neuropathy is not a sufficiently characteristic correlate of the syndrome. On the other hand, spectral analysis of sway on stressful positions involving head turning appears to differentiate diabetic neuropathy from other disorders involving postural disturbances.

An initial evaluation of work fatigue and circadian changes as assessed by multiplate posturography.

The sensitivity of postural responses to the effects of work fatigue and circadian changes was explored in a pilot study using a specific method of multiplate posturography based on the differential assessment of vertical pressure on four separate platforms for each heel and set of toes of each foot, respectively 8 normal subjects, M.D.s, were given six posturographic examinations immediately before and after three 8-hr. work shifts in the emergency room of a major hospital in Tel-Aviv. 3 posturographic measures (stability, spectral power of postural sway at low frequency of 0.1-0.25 Hz, and unilateral weakening of heel-toe synchronisation) were significantly affected by work fatigue whilst also showing interaction with circadian rhythm. 2 additional measures (power of sway at high frequency of 1.00-3.00 Hz and dysharmonic distribution of weight over the four platforms) were not related to workload but showed significant circadian changes. These effects appeared only on positions involving restricted visual and somatosensory feedback causing vestibular stress. Results justify the application of multiplate posturography as an ancillary tool in measuring objectively the effects of fatigue and circadian changes as well as the interaction between endogenous chronobiological processes and their external conditioning factors (Zeitgebers). Pragmatic implications of the findings in the context of industrial medicine and interdisciplinary efforts to prevent road and air accidents are discussed.

Postural control in pilots and candidates for flight training.

Postural control may reflect the pilot's ability to deal successfully with the stresses of spatial orientation. In this study, we hypothesized that fighter pilots would have better performance on the "tetra-axiametric posture test" than would helicopter pilots (less rigorously selected) and candidates for flight training. We tested 28 fighter pilots, 23 helicopter pilots and 43 candidates by tetra-axiametric posturography. Fighter pilots were found on the level position to have significantly more compensatory anterior-posterior sway (moving anterior-posterior rather than laterally, p = 0.02) and required less movements to maintain balance (p = 0.02) than did candidates. Helicopter pilots had intermediate values. In stressed positions, fighter pilots demonstrated relatively more slow movements (p = 0.018) than did the candidates, which may be related to increased labyrinth control. In the stressed positions, helicopter pilots had postural profiles similar to the candidates. We conclude that there are significant differences in postural control as tested by tetraaxiametric posturography between fighter pilots, helicopter pilots, and candidates for flight training. This could be due to either innate ability, which could be used in the selection process, or to training. A prospective study is planned in order to determine if posturography can predict a candidate's ability to complete flight training.

Postural control in children with autism.

Postural control was evaluated in samples of autistic, normal, and mentally retarded children in this pilot study using a recently developed, computerized posturographic procedure. A battery of postural positions was administered including postures involving some degree of "stress" (e.g., occluded vision or standing on pads). The postural patterns of children with autism differed from those observed in normal children, in mentally retarded children, and in adults with vestibular disorders. In comparison to normal children the autistic subjects were less likely to exhibit age-related changes in postural performance and postures were more variable and less stable with more lateral sway. Autistic subjects also exhibited a "paradoxical" response of greater stability with more "stressful" postures, putting excessive weight on one foot, one toe, or one heel. The implications for neuroanatomical models of autism are discussed.

Application of tetra-ataxiametric posturography in clinical and developmental diagnosis.

Tetra-ataxiametric posturography is based on the measurement and computerized elaboration of electronic signals emitted by four footplates, one for each heel and toe, respectively. These are sensitive to vertical pressure produced by a subject standing straight but in various positions (feet parallel, in tandem, eyes closed, on pads, etc.). The method yields additional parameters not obtained by the traditional monoplate stabilometers, namely, weight-distribution patterns and correlations among six combinations of paired outputs from the two heels, two toes, heel/toe of each foot, and the two diagonals (tetra-ataxiametric synchronisations). Comparing age-matched learning disabled, mentally retarded, autistic, and hearing impaired (with and without labyrinthine hypofunction) with normal children, significant and clinically meaningful differences were detected between the tetra-ataxiametric measures of stability, interaction between Fourier Spectral Power Ranges of body sway, weight distributions, and synchronisations of toe parts. The same parameters correlated significantly with cognitive school readiness in normal populations. While the stability and spectral quotients show significant developmental changes, weight distribution and toe synchronisations are stable from 5 years onwards. The method is suitable for young subjects and attractive to children who may ordinarily be reluctant to cooperate, such as the autistic ones. The equipment is portable and tests can be conveniently carried out in a child's familiar educational setting.

Relations of basic arithmetic and motor skills in deaf elementary school children.

3 segregated groups of Arab and Jewish deaf children of CA 10;9 (n = 28) were compared with a group of hearing Arab first graders (CA = 6;10, n = 32) on tests of basic arithmetic, static balance control, and the ability to suppress synkinetic finger movements. The hearing-impaired performed as well on arithmetic tasks and on the tests of synkinetic control as their normal peers who were four years younger, while on static balance they were even inferior to the latter. Significant correlations were found between the basic arithmetic and motor skills, within the hearing as well as within the hearing-impaired groups; these remained significant even within the small subgroups of the latter. As these results cannot be accounted for by low intelligence and neurological disturbances, or by direct or indirect effects of deficient language development, the assumption is supported that some type of neurological immaturity, unrelated to hearing loss, interferes with the acquisition of numerical skills in deaf children.

Some observations on tetra-ataxiametric patterns of static balance and their relation to mental and scholastic achievements.

Recent experiences and observations gathered in the context of six independent studies in California, France, and Israel with a new method of tetra-ataxiametry based on the use of four footplates, are presented. Two independent postural parameters assessed by this method (fluctuations and anterio-posterior weight displacement) have been shown to be reliable over time and to correlate with scholastic progress at the lower elementary grades (ages 5 to 9 yr.). They also seem to be sensitive to minimal neurological dysfunction and to postural characteristics of deaf children. Results of one study indicate that diagonal balancing movements (between heel and contra-lateral toe) reflected by the tetra-ataxiametric measure of synchrony may play an important role in postural organization. Findings offer new perspectives on problems of postural laterality and on the relationship between static balance, cognition, and scholastic aptitudes at the lower grades of elementary education.

Association between maternal bleeding during gestation and congenital anomalies in the offspring.

The incidence of maternal bleeding complicating the pregnancies of 326 children examined at the Jerusalem Community Center for Child and Family Development is surveyed. A history of bleeding during pregnancy was more frequent in children with congenital anomalies of the central nervous system (and/or psychomotor retardation) (33 per cent) and in children with congenital anomalies of other systems (29 per cent) than in control children (12 per cent). The implications of these findings are discussed in relation to placental pathophysiology and the pathogenesis of threatened abortion.

A post-residential-treatment follow-up of socially and emotionally deviant adolescents in Israel.

Fifty-five emotionally and socially deviant but normally intelligent adolescents who had spent 2-7 years in a children's and apprentice home in Israel were followed up 5-9 years after they had left the institution. Their postresidential social and vocational careers were evaluated by means of personal interviews, home visits, and reports from employers, and it was found that good adjustment was substantially related to family background variables (having lived with biological parents prior to residential placement, mutual positive relationship between parent and child, being first born) as well as to satisfactory behavior and performance in peer group, school, and workshop during residence. Level of intelligence, unrelated to overall adjustment, correlated positively with vocational status and income at followup. On the other hand, length of stay in the apprentice home had no impact on postresidential adaptation to work and society. Fewer than 10% of exinmates expressed retrospectively a negative attitude toward their stay in the institution. The importance of paying more attention to the eventual long-term and enduring impact of family relationship on the residential and postresidential behavior of adolescents is discussed, suggesting a shift of emphasis in evaluating factors involved in institutional treatment. Findings also indicate that later social and vocational success may be fairly predicted from observation of behavior during the stay in the institution.

Early assessment and prevention of sociocultural deprivation in infancy.

The Bayley Infant Scales are used to diagnose early socio-cultural deprivation. It seems to be possible to observe early syndromes of pure environmental stress, as against syndromes of neurological damage, as well as syndromes of mixed traumatisation. There are also types of inadequate mothers in the low and lowest socio-cultural milieu who produce typical behavioral deficiencies in organically healthy infants. On the basis of a Scalogram Analysis of the Bayley Scales a structured stimulation technique has been designed which can be easily taught to and administered by professionals, semiprofessionals, volunteers and the parents themselves. Some case histories are presented to demonstrate the efficiency of the diagnostic and intervention procedures.