Electrophysiological Assessment of Sensations Arising from the Bladder: Are there Objective Criteria for Subjective Perceptions?
University of Zurich, Zürich, Zurich, Switzerland The Journal of Urology
(Impact Factor: 4.47).
02/2003; 169(1):190-4. DOI: 10.1097/01.ju.0000035362.27178.99
Initial bladder filling sensation, first and strong desire to void are subjective perceptions that occur periodically during the urine storage mode of bladder function, representing sensory input from the lower urinary tract. To our knowledge methods for evaluating sensory bladder function are not available. We studied a simple electrophysiological procedure for the objective assessment of bladder sensations using sympathetic skin responses and surface pelvic floor electromyography.
Informed consent was provided by 8 healthy male subjects, who were administered 20 mg. furosemide and 1 l. fluid to drink. Palmar and plantar sympathetic skin responses, and surface pelvic floor electromyogram were continuously recorded during bladder filling, voluntary pelvic floor contraction and voiding.
First desire to void evoked simultaneous sympathetic skin responses and pelvic floor contractions. This pattern appeared periodically with the desire to void sensation as well as with strong desire to void at maximum bladder capacity and it correlated well with the subjective sensation of the subjects. Voluntary pelvic floor contraction decreased the subjective intensity of the desire to void sensation as well as sympathetic skin response activity for the same short period. During voiding sympathetic skin responses almost complete absence of sympathetic skin responses was observed.
Sensations arising from the bladder induce combined activation of sympathetic skin responses and pelvic floor activity. This coherence indicates synchronized activation and inactivation of the autonomic and somatic pathways necessary for appropriate urine storage and coordinated voiding. Our observations may introduce a new approach for objectively assessing subjective sensations arising from the urinary tract.
Available from: Simon Podnar
- "Generally, the EMG signal is described only qualitatively. However, quantitative techniques are also available (i.e., measurement of the area under the rectified signal), which increase the validity of the findings (Reitz et al., 2003a). "
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ABSTRACT: The nervous system structures involved in the control of the lower urinary tract (LUT) are usually divided using a neuroanatomical classification system into suprapontine, pontine, spinal and sacral. In all patients with LUT symptoms, after exclusion of local causes, a nervous system disorder needs to be considered. For the diagnosis of neurogenic LUT disorders, in addition to clinical assessment, neurophysiologic testing might be useful. Imaging and other laboratory studies (e.g., cystometry) often provide relevant additional information. Neurophysiologic tests are more useful in patients with sacral compared with suprasacral disorders. Although in patients with LUT disorders external urethral sphincter (EUS) electromyography (EMG) would seem the most appropriate, anal sphincter EMG is the single most useful diagnostic test, particularly for focal sacral lesions, and atypical parkinsonism. Another clinically useful method that tests the sacral segments, and complements EMG, is the sacral (penilo/clitoro-cavernosus) reflex. Kinesiologic EMG is useful to demonstrate detrusor sphincter dyssynergia (i.e., increased EUS activity during bladder contraction), which is particularly common in spinal cord disease. Somatosensory evoked potential (SEP) and motor evoked potential (MEP) studies (cortical and lumbar) may be useful to diagnose clinically silent central lesions. MEP, in addition, seems to be very promising in research into cortical excitability. Theoretically, cortical SEP on bladder/urethra stimulation would be much more useful than pudendal SEP because it tests thin nerve afferents from the pelvic viscera. However, the utility of this technique is limited by technical difficulties, which can be partially overcome by the concomitant recording of a palmar sympathetic skin response (SSR). SSR recorded from the saddle region is also useful for testing the lumbosacral sympathetic system. Although the technique of detrusor EMG has been recently described in humans, a clinically useful test for evaluating the sacral parasympathetic system, which is crucial for LUT functioning, is still lacking.
Available from: Armin Curt
- "Making use of the fMRI technique, the aim of this study was to investigate the brain structures involved in voluntary control of bladder function: in colloquial terms, to answer the question: bWhich areas in the brain are involved in the voluntary control of the micturition?Q Derived from earlier urology study (Reitz et al., 2003), it is hypothesized that these areas' activity triggered by pelvic floor muscle contraction will increase when bladder is full, since the filled bladder has almost no room for urine holding; therefore any pelvic floor muscle action would dramatically arouse desire to void and suppression of such desire, since it is not allowed to urinate in the scanner, thereby we have established a nonvoiding model (i.e., active pelvic floor muscle contraction with full bladder to induce stronger desire to void and micturition reflex inhibition, since the subject is not allowed to urinate) of inhibitory bladder control. The model involves the performance of repetitive pelvic floor muscle contraction in alternation with periods of rest under full (FBC)-and empty (EBC)-bladder conditions. "
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ABSTRACT: We have learned that micturition is comprised of two basic phases: storage and emptying; during bladder emptying, the pontine and periaqueductal gray (PAG) micturition center ensures coordinated inhibition of striated sphincter and pelvic floor muscles and relaxation of the internal urethral sphincter while the detrusor muscle contracts. Due to several disorders of the brain and spinal cord, the achieved voluntary control of bladder function can be impaired, and involuntary mechanisms of bladder activation again become evident. However, little has been discovered so far how higher brain centers strictly regulate the intricate process of micturition. The present functional magnetic resonance imaging (fMRI) study attempted to identify brain areas involved in such voluntary control of the micturition reflex by performing functional magnetic resonance imaging during a block design experiment in 12 healthy subjects. The protocol consisted of alternating periods of rest and pelvic muscle contraction during empty-bladder condition (EBC) and full-bladder condition (FBC). Repeated pelvic floor muscle contractions were performed during full bladder to induce a stronger contrast of bladder sensation, desire to void and inhibition of the micturition reflex triggering, since the subjects were asked not to urinate. Empty-bladder conditions were applied as control groups. Activation maps calculated by contrast of subtracting the two different conditions were purposed to disclose these brain areas that are involved during the inhibition of the micturition reflex, in which contrast, the SMA, bilateral putamen, right parietal cortex, right limbic system, and right cerebellum were found activated. The combined activation of basal ganglia, parietal cortex, limbic system, and cerebellum might support the assumption that a complex visceral sensory-motor program is involved during the inhibitory control of the micturition reflex.
Available from: Simon Podnar
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ABSTRACT: For the diagnosis of neurogenic bladder, in addition to clinical assessment, neurophysiologic testing may be useful. Neurophysiologic
tests are more useful in patients with sacral compared with suprasacral disorders. Anal sphincter electromyography (EMG) is
the most useful diagnostic test, particularly for focal sacral lesions and atypical parkinsonism. Another clinically useful
method that tests the sacral segments and complements EMG is the sacral (penilo/clitoro-cavernosus) reflex. Kinesiologic EMG
is useful to demonstrate detrusor sphincter dyssynergia. Somatosensory-evoked potential and motor-evoked potential studies
may be useful to diagnose clinically silent central lesions. The utility of cortical somatosensory-evoked potential in bladder/urethra
stimulation is limited by technical difficulties that can be partially overcome by the concomitant recording of a palmar sympathetic
skin response. Sympathetic skin response recorded from the saddle region is also useful for testing the lumbosacral sympathetic
system. A clinically useful neurophysiologic test for evaluating the sacral parasympathetic system is still lacking.
KeywordsElectromyography-Lower urinary tract-Motor-evoked potentials-Neurogenic bladder-Somatosensory-evoked potentials-Sympathetic skin response-Voiding
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