Carotid baroreflex function ceases during vasovagal syncope

Abstract. Despite the arterial baroreflex control of heart rate and blood pressure, vasovagal syncope is a common cause of loss of consciousness in people exposed to stimuli that reduce the central blood volume, such as head-up tilt. Carotid baroreflex function was evaluated using a rapid pulse train of neck pressure and neck suction in three conscious volunteers who developed a vasovagal episode during head-up tilt. The maximal gain of the carotid-heart rate and carotid-blood pressure baroreflex function curves were identified as measures of carotid baroreceptor responsiveness. When presyncopal symptoms developed, one further baroreflex assessment was obtained before the subjects were returned to the supine position. The bradycardia and hypotension exhibited during pre-syncope and syncope reflected a leftward and downward relocation of both the cardiac and vasomotor stimulusresponse curves. In addition, during the vasovagal syncope, baroreflex control was suppressed as blood pressure remained low during neck pressure stimuli. In conclusion, arterial baroreflex function ceases during vasovagal syncope.     

Supporting insensitive mothers: the Vilnius randomized control trial of video-feedback intervention to promote maternal sensitivity and infant attachment security

Objective   This randomized control trial examined the effects of a short-term, interaction-focused and attachment-based video-feedback intervention (VIPP: video-feedback intervention to promote positive parenting).
Design   VIPP effect on mothers' sensitive responsiveness and infant–mother attachment security was evaluated in a sample ( n  = 54) of low sensitive, non-clinical, middle class Lithuanian mothers.
Methods   Maternal sensitivity was assessed in a free play session with the Ainsworth's sensitivity scale, and attachment security was observed using the Attachment Q sort for home observations.
Results   We found that the intervention mothers indeed significantly improved their sensitive responsiveness through participation in our VIPP. The effect size was large according to Cohen's criteria, d  = 0.78. VIPP enhanced maternal sensitive responsiveness even when maternal age, educational level, depression, daily hassles, efficacy, infant gender, and infant negative and positive affect were controlled for. However, attachment security in the VIPP infants was not enhanced after the intervention, compared with the control infants, and the infants did not seem to be differentially susceptible to the increase in maternal sensitivity dependent on their temperamental reactivity.
Conclusion   We suggest that a relatively brief and low-cost programme can provide effective support for mothers who lack sensitivity in the interactions with their infants.     

Effects of stress and shock anticipation on prepulse inhibition of the startle reflex

The effects of shock anticipation and attention to external stimuli on prepulse inhibition (PPI) were compared. In the threat-of-shock experiment, acoustic startle stimuli were presented with and without prepulses when aversive shocks were or were not anticipated. In the control experiment, startle and prepulse stimuli were delivered during periods with attended or ignored external stimuli. In the threat-of-shock experiment, startle was potentiated (fear-potentiated startle) and PPI was increased by shock anticipation. A gradual reduction in the overall PPI throughout the experiment was also found. In the control experiment, only PPI was increased in the attend condition. The PPI level remained constant throughout the experiment. The increase in PPI in the threat and attend conditions may have resulted from an increase in the general level of alertness that facilitated the processing of the prepulse. The gradual decrease in PPI in the threat experiment was hypothesized to result from a progressive deficit in sensory functioning due to the stressful nature of repeated shock anticipation.     

Vesico-anal influences in healthy intact humans: Quantificated by responses in the external anal sphincter following transcranial cortical stimulation

EMG responses in the external anal sphincter (EAS), the rectus abdominis muscle (RA), and the anterior tibial muscle (TA) were recorded following single magnetic transcranial cortical stimulations (TCCS) in seven healthy volunteers. The responses in the EAS differed from the responses in the other muscles. They had comparatively long durations ranging from 1 to 2 seconds, no inhibitory periods were observed, and there was no tendency for habituation to occur following a limited number of stimuli. The responses recorded in the EAS were used as test responses in order to evaluate the excitability changes in the EAS motoneurons occurring during bladder filling. Cystometries with filling rates of 15, 50 and 200 ml/min were done. During these cystometries TCCS were applied repeatedly, with constant strength, after each 50 ml of filling up to bladder capacity. The responses following TCCS changed in a highly reproducible way during bladder filling. After 100–200 ml of filling, the responses had longer latencies, diminished sizes, and shorter durations. When the filling reached a level 50–150 ml below capacity, the responses in most subjects again became greater and the latencies shorter. The changes were believed to be physiological. It was concluded that the EAS motoneurons are under both inhibitory and facilitatory influence during bladder filling in intact healthy humans. Facilitatory influences are often observed when the bladder is filled close to capacity. At lower bladder volumes the observed influence is always inhibitory. A decrease in the EMG activity of the EAS during filling cystometry should consequently not be regarded as a pathological response.     

CMSS-VEPs: Contrast modulated steady state visual evoked potentials: Its neuronal origin and clinical use

CMSS-VEPs are presented as a sensitive, non-invasive functional investigation technique of the visual function, applicable in clinical practice. New improvements of the technique are presented. The underlying neuronal mechanisms are discussed. The clinical use is illustrated in a case of optic neuritis.     

Nipple sensitivity and lactation in two methods of breast reduction

Two methods of breast reduction were performed between 1981 and 1986. One was wedge resection of the breast in which nipple and gland were disconnected. The other was the tangential and circumferential breast reduction, in which the nipple remained in continuity with the gland. For each method, there were 21 patients. The mean follow-up was 5 years and 9 months. In both groups, 8 patients had 11 children, but only the tangential reduction patients lactated. They also had better subjective nipple sensitivity whereas objectively the differences were rather small.     

Reduced genital sensitivity in female patients with multiple system atrophy of parkinsonian type.

According to the consensus statement on the diagnosis of multiple system atrophy (MSA), erectile dysfunction is required for male patients to fulfil the urinary incontinence criterion. However, there is no equivalent item for female patients. We questioned 19 female patients with MSA of the parkinsonian type (MSA-P), 28 female patients with Parkinson's disease (PD), and 27 healthy controls on their genital sensitivity. A total of 47% of the MSA patients but only 4% of the PD patients and 4% of the control group admitted to reduced genital sensitivity, a highly significant difference (P < 0.001). Moreover, the appearance of reduced genital sensitivity in female MSA patients showed a close temporal relation to the onset of the disease. If these preliminary results can be confirmed and further specified in a larger sample, a historical item of reduced genital sensitivity in female patients might become a diagnostic feature for MSA, comparable to erectile dysfunction in male patients.     

Rectal sensorimotor characteristics in female patients with idiopathic constipation with or without paradoxical sphincter contraction

Patients with chronic constipation fulfilling the Thompson criteria can show paradoxical sphincter contraction. Aim of this study was to evaluate rectal sensorimotor characteristics in patients with constipation with or without paradoxical sphincter contraction. Thirty female patients with chronic constipation and 22 female controls were investigated with anal manometry and rectal barostat. Paradoxical sphincter contraction was shown with manometry as a paradoxical increase of anal pressure during straining. Visceral sensitivity and compliance were tested by intermittent and continuous pressure-controlled distension. Patients were classified according to their sensations and compliance into normal, hypersensitive, reduced compliant, insensitive or excessive compliant rectum. Postprandial rectal response (PRR) and phasic volume events (PVEs) were registered for 1 h after a 600-kCal meal. Paradoxical sphincter contraction was found in 13 (43%) patients. In these patients, rectal sensitivity scores were higher (P = 0.045) than in patients without paradoxical contractions, but rectal compliance was not different. In 90% of patients an abnormal rectal sensitivity or compliance was found: excessively compliant in 35%, reduced compliant in 10%, hypersensitive in 27% and hyposensitive in 17%. Both patients with constipation (11%; P = 0.042) and controls (25%; P = 0.002) exhibited the presence of a postprandial rectal response. This response was not significantly different between idiopathic constipation, paradoxical sphincter contraction and controls. Patients with rectal hypersensitivity had lower response than other patients (P = 0.04). Patients with constipation had fewer basal PVEs compared controls (P = 0.03). Postprandial PVEs increased in both patients (P = 0.014) and controls (P < 0.001). Postprandial rectal response and PVE were not different in patients with or without paradoxical sphincter contraction. A total of 90% of female patients with idiopathic constipation show an abnormality in rectal sensation or compliance. The postprandial rectal response was comparable between patients with constipation and controls, however, PVEs were diminished. Patients with paradoxical sphincter contraction had higher rectal sensitivity but an unaltered compliance and postprandial rectal response. Future trials should investigate whether the classification of rectal abnormalities in patients with constipation has clinical importance.     

Movement disorders in patients with peripheral facial palsy.

Acute unilateral facial paralysis is usually a benign neurological condition that resolves in a few weeks. However, it can also be the source of a transient or long-lasting severe motor dysfunction, featuring disorders of automatic and voluntary movement. This review is organized according to the two most easily recognizable phases in the evolution of facial paralysis: (1). Just after presentation of facial palsy, patients may exhibit an increase in their spontaneous blinking rate as well as a sustained low-level contraction of the muscles of the nonparalyzed side, occasionally leading to blepharospasm-like muscle activity. This finding may be due to an increase in the excitability of facial motoneurons and brainstem interneurons mediating trigeminofacial reflexes. (2). If axonal damage has occurred, axonal regeneration beginning at approximately 3 months after the lesion leads inevitably to clinically evident or subclinical hyperactivity of the previously paralyzed hemifacial muscles. The full-blown postparalytic facial syndrome consists of synkinesis, myokymia, and unwanted hemifacial mass contractions accompanying normal facial movements. The syndrome has probably multiple pathophysiological mechanisms, including abnormal axonal branching after aberrant axonal regeneration and enhanced facial motoneuronal excitability. Although the syndrome is relieved with local injections of botulinum toxin, fear of such uncomfortable contractions may lead the patients to avoid certain facial movements, with the implications that this behavior might have on their emotional expressions.