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PubMed1999

[Bechterew phenomenon in the human].

BACKGROUND: Vestibuloocular and vestibulospinal reactions following the bilateral loss of vestibular function are designated as Bechterew's phenomenon. In vestibular physiology, under experimental conditions, this phenomenon has played an important role for understanding the mechanisms underlying vestibular compensation. However, clinical reports about this phenomenon in humans are extremely rare. PATIENTS AND METHODS: Bechterew's phenomen was observed throughout every stage of its development in a patient with consecutive bilateral loss of vestibular function. The disorder was documented by electronystagmography and posturography. DISCUSSION AND CONCLUSIONS: Bechterew's phenomenon depends on different states of vestibular function developing in a certain succession, whereby the varying relations between failure and compensation are decisive. The phenomen very impressively demonstrates the resilience of the central nervous system in adapting to varying peripheral functional states. From a clinical standpoint, knowledge of these relationships is important for understanding vestibular compensation.

Electronystagmography↗
PubMed1982

Neurological and neurobehavioural differences between preterm infants at term and full-term newborn infants.

A detailed neurological and neurobehavioural examination was done in 80 preterm infants of 27 to 35 weeks gestation in the first week of life and again at 40 weeks postmenstrual age, and in 40 appropriately-sized full-term infants on the first and fifth days of life. There were several consistent differences between the preterm infants reaching term and the newborn full-term infants. The preterm infants reaching 40 weeks showed less flexion in their posture, and less arm traction, arm recoil and leg recoil than the full-term infants on day 1, although this difference was less apparent by day 5. The preterm infants appeared not to develop the flexor tone of the full-term newborn. The preterm infants demonstrated better visual and auditory orientation and alertness than the full-term infants. The significance of these findings, both for initial neonatal examinations and for subsequent assessments, is evaluated.

Arousal↗
PubMed2003

Contribution of the vestibular apparatus to postural control when rising from a chair.

OBJECTIVE: The everyday act of rising from a chair is known to require the combined angular control of a number of the body's joints, especially those within the pitch plane. Precisely how this control is exerted, however, remains controversial. The aim of this study was to obtain a better understanding of the contribution made by the vestibular apparatus to postural control of the body and head when an individual rises from a chair. MATERIAL AND METHODS: A total of 24 healthy controls and 38 patients with varying degrees of vestibular dysfunction were examined. Electromagnetic motion sensors were used to analyze the angular control of the head and body as subjects rose from a chair with their eyes open or closed. RESULTS: We found that unilateral vestibular dysfunction caused fixation of the head with respect to the body, resulting in a loss of spatial stability of the head which was not compensated for by visual input. Visual input did appear to compensate for bilateral vestibular loss, enabling patients with bilateral vestibular apparatus impairment or central disorders to fix the position of their head in space. CONCLUSION: The act of rising from a chair is normally controlled by vestibular and proprioceptive input; the head is aligned according to the gravitational reference so as to obtain stable visual information. In patients with unilateral vestibular hypofunction, posture is still controlled by these two inputs, although the ability to align the head is diminished. In patients with bilateral vestibular hypofunction or a central disorder, head alignment is maintained using visual input, although it may not be the sole or predominant stabilizing force.

Adult↗
PubMed2003

Effect of low body temperature during unilateral labyrinthectomy on vestibular compensation in the guinea pig.

OBJECTIVES: Vestibular compensation, the recovery that follows unilateral vestibular deafferentation (UVD), is a model for central nervous system plasticity. Recovery from the static symptoms of UVD may involve temperature-dependent processes that modulate the immediate effects of UVD and/or the capability of the central nervous system to undergo adaptive plasticity. In this study we investigated changes in oculomotor and postural vestibular symptoms resulting from low body temperature during UVD. MATERIAL AND METHODS: To study the effect of low temperatures at the time of UVD on vestibular compensation, we compared the rate of compensation and peak values for postural [roll head tilt (RHT) and yaw head tilt (YHT)] and oculomotor [spontaneous nystagmus (SN)] symptoms in three groups of guinea pigs. Animals in Group 1 (n = 6) were maintained at 38 degrees C throughout unilateral labyrinthectomy (UL). Animals in Group 2 (n = 6) were not temperature-controlled and animals in Group 3 (n = 4) were cooled with ice to 25 degrees C throughout UL. RESULTS: Cooled animals showed significantly higher rates of SN upon recovery from anaesthesia and took a significantly longer time to compensate. Cooled animals were also slower to compensate for postural symptoms (RHT and YHT), with 2 animals showing no compensation for RHT 52 h after UL. CONCLUSION: Hypothermia (25 degrees C) during UVD surgery exacerbates postural and oculomotor symptoms following UL and significantly slows recovery.

Animals↗
PubMed1984

Autonomic dysreflexia (hyperreflexia).

This author has presented his personal experience and observations concerning acute and chronic dysreflexia. The various causes of dysreflexia are discussed. The importance of bladder balance is stressed as the number one cause with the anorectal site being second. The methods of treatment that the author uses for both acute and chronic dysreflexia are described.

Antihypertensive Agents↗
PubMed2002

A comparison of sympathetic outflow to muscles between cervical spondylotic amyotrophy and ALS.

To confirm the diagnostic usefulness of muscle sympathetic nerve activity (MSNA) in differentiation between cervical spondylotic amyotrophy (CSA) and amyotrophic lateral sclerosis (ALS) with cervical spondylosis (CS), MSNA, heart rate (HR) and blood pressure (BP) were recorded in 10 patients with CSA and ALS with CS, and age-matched healthy volunteers at rest and during head-up tilting. There were no differences in age, disability scores, pulmonary function, and HR or BP at rest between ALS and CSA groups. Resting MSNA was significantly greater in patients with ALS with CS than in comparison groups (P<0.001) with virtually no overlap between ALS and the CSA groups. During head-up tilting, changes in BP and MSNA were significantly less in patients with ALS than in patients with other subjects. MSNA at rest clearly differentiated CSA from ALS with CS, suggesting diagnostic utility.

Age Factors↗
PubMed1983

Age-related changes in autonomic function: relationship with postural hypotension.

Eleven elderly subjects, six with signs and symptoms of postural hypotension, were investigated for autonomic neuropathy of their cardiovascular and pupillary systems. The results were compared with those from a group of nine young subjects to define the reductions in autonomic activity that normally occur with age. There was evidence of a decline in autonomic function in the elderly, but this was no greater in the group with postural hypotension. A positive correlation was found between the level of the supine systolic pressure and the degree of postural drop. It is suggested that pathology in the vasculature and not in the sympathetic innervation is responsible for postural hypotension in the elderly.

Adult↗
PubMed1991

Response to the cold pressor test in normotensive and hypertensive patients.

The response to the cold pressor test (CPT) was studied in 49 normotensive (NT) and 73 patients with essential sustained hypertension (HT). Patients were classified as responders when they increased their systolic pressure (SBP) by at least 16 mm Hg or their diastolic blood pressure (DBP) by at least 12 mm Hg. Forty-seven out of seventy-three (64%) increased their mean blood pressure (MBP) by 18.6 +/- 1.4 mm Hg (mean +/- SEM) in response to CPT. In NT subjects 23 out of 49 (47%) were responders (MBP = 16.3 +/- 1.3 mm Hg). In NT, but not in HT, patients, a negative relationship was observed between MBP changes during CPT and age (P less than .001) or basal DBP (P less than .01). There was no relationship between blood pressure response and the presence of a family history of hypertension. A positive correlation was found in HT patients between basal levels of active renin (AR) in the upright position and MBP changes during CPT (P less than .001). Mean plasma AR was 24.2 +/- 3.5 pg/mL in nonresponders v 37.5 +/- 2.9 pg/mL in responders (P less than .001). In HT, but not in NT, patients, blood pressure changes were associated with a simultaneous increase in HR (P less than .01 between delta MBP and delta HR). These results suggest that blood pressure elevation during CPT is a very common reaction in young normotensive subjects especially in those that have the lowest mean blood pressure. Therefore it is unlikely that CPT may be used as a predictor test of future hypertension in this population.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1987

Pathological eye-head coordination in roll: tonic ocular tilt reaction in mesencephalic and medullary lesions.

The fundamental pattern of coordinated eye-head roll motion is based upon utricular/saccular as well as vertical canal input, and mediated by the graviceptive pathways from the labyrinths via pontomedullary vestibular nuclei to the rostral midbrain tegmentum. The tonic bilateral graviceptive input stabilizes the eyes and head in the normal upright position. A unilateral lesion causes imbalance in vestibular tone in the roll plane which results in a tonic ipsiversive ocular tilt reaction (OTR). OTR, the triad of ipsilateral head tilt, skew deviation and ocular torsion, occurred as a tonic response (nonparoxysmal) persisting over months to years and was presumed to be due to upper brainstem lesions in 3 patients. Precise localization was limited because of the nature of the lesions. A reversible tonic OTR was seen with acute infarction of the dorsolateral medulla oblongata in 4 out of 11 patients. It may be explained by an ipsilateral lesion of the posterior canal pathways. Transient OTR seems not to be rare in acute Wallenberg's syndrome and ocular torsion in these patients is dysconjugate with predominant excyclotropia of the ipsilateral hypotropic eye. A deviation of the subjective visual vertical in the direction of the spontaneous head tilt--a previously undescribed feature of OTR--was present in all 7 patients and indicates a pathological shift of the internal representation of the gravitational vector. With respect to perception (subjective vertical) it is proposed that the manifest ipsiversive OTR represents a motor compensation of an apparent eye-head tilt contraversive to the lesioned side. Despite the resulting postural imbalance and the conflicting true vertical of the visual surround, the eyes, head and body are continuously adjusted to what the central nervous system erroneously computes as being vertical.

Adult↗