Effect of nerve length and temperature on the induction of action potentials in denervated slow muscle fibres of the frog

A. Pyriformis and extensor longus digiti IV muscles of Rana temporaria were denervated by cutting the sciatic or peroneal nerve at various distances from the muscles. Slow fibres were identified by their membrane time constants, and examined for their ability to produce action potentials in response to intracellularly applied current pulses. B. The slow muscle fibres acquired the ability to generate action potentials several days after denervation. The duration of this latent period depended on the length of the peripheral nerve stump, and on the temperature at which the frogs were kept after the operation. C. At 18 degrees C the latent period increased by 0.36 days per mm of sciatic nerve stump. At 11.5 degrees C the corresponding value was 0.7 days/mm. The effect of length of the peroneal nerve was smaller than that of the sciatic nerve. D. It is suggested that the peripheral nerve stump serves as a reservoir of 'trophic' material which is transported towards the slow fibres at a rate of 2.8 mm/day (at 18 degrees C) and seems to block the formation of Na channels. The Q10 value of this transport system would be 2.7.     

Coordination dynamics in Parkinson's disease patients and healthy subjects quantified by the coordination dynamics recording method and sEMG

Coordination dynamics were measured in Parkinson's disease patients to quantify central nervous system (CNS) dysfunction. The low-load coordination dynamics in the patients were impaired by 56% for forward and 44% for backward moving in comparison to a control group of similar age. Exercising at higher load was only partly possible. When the disease preferentially affected one side of the body, the coordination dynamics were worse for the affected side. A dexterity test showed that coordination of hand and arm movements could be improved in the short-term memory when exercising on the special coordination dynamics recording and therapy device. Simultaneously taken surface EMG (sEMG) showed that the motor pattern was impaired in the Parkinson's disease patients. sEMG recordings showed further that the fast fatigable muscle fibre activation was impaired. FF-type muscle fibres were already activated for low load in one and not at all in another muscle. In conclusion, coordination between motoneuron firings and between arm and leg movements were found to be impaired in Parkinson's disease patients.     

Integrative re-organization mechanism for reducing tremor in Parkinson's disease patients

A special movement therapy, called coordination dynamics therapy, has been reported to have the potential to improve central nervous system (CNS) functioning in Parkinson's disease patients. Electromyography using surface electrodes (sEMG) showed that the rhythmic muscle activity leading to Parkinsonian tremor was generated in the patients by the impairment of two kinds of inhibition. First, some premotor spinal oscillators organized themselves in the CNS neuronal networks without strong adequate input and second, the oscillators synchronized their firing to give rise to rhythmic muscle activity and tremor. In this paper it will be shown that highly coordinated arm and leg movements, generated when exercising on a special coordination dynamics therapy device, can reduce Parkinsonian tremor in amplitude and frequency and improve CNS functioning in the short-term memory. sEMG measurements showed upon exercising on the special coordination dynamics therapy device that the motor program improved in the short-term memory and tremor muscle activity became coordinated with the volitional motor program and reduced in size and frequency. Higher load exercising seemed to better reduce tremor muscle activity, probably because the physiologic CNS organization was more integrative then and could 'bind' stronger simultaneous pathologic tremor activity. Moreover, the rhythmic synchronized motor unit firing in different arm and leg muscles was synchronized or coordinated and changed in frequency and amplitude. It is concluded that the integrative re-organization mechanism to reduce Parkinsonian tremor is the phase and frequency coordination between neuron firing of the physiologic neuronal network state, generated by the highly coordinated arm and leg movements, and the simultaneous pathologic tremor network state, generated by the uninhibited neurons, firing synchronized oscillatory.     

Phase and frequency coordination between neuron firing as an integrative mechanism of human CNS self-organization

It was shown by surface electromyography (sEMG) from spinal cord injury and Parkinson's disease patients that FF-type motor units fire repeatedly at a rate of 10 Hz and FR-type motor units with approximately 3 action potentials per impulse train at 4 to 5 Hz. Such oscillatory firing was compared with the firing of alpha1, alpha2, and alpha3-motoneurons, innervating FF FR, and S-type muscle fibres, which fire oscillatory approximately at 10 Hz, 4 to 7 Hz and 1 Hz, as measured earlier with the single nerve-fibre action potential recording method from motoneuron axons. Repeated firings with impulse trains consisted of 1, 2-5, and 20-50 action potentials per impulse train respectively. Oscillatory firing of motoneurons has now been demonstrated in humans with two methods. In spinal cord injury patients it was observed that the FF-type motor units, firing normally at 10 Hz, fired for higher activations also at approximately 20 Hz. A motor program burst was generated by recruiting for the burst time motor units to fire oscillatory. It was further shown that FF-type motor units fired with relative phase and frequency coordination but non-synchronously. The coordination was between motor units firing of the same muscle and between muscles of the right and left arm. With the single-nerve fibre action potential recording method it was found earlier that alpha and gamma-motoneurons and muscle spindle afferents fired in relative coordination. There is indication that relative phase and frequency coordination is an integrative mechanism for the self-organization of the neuronal networks of the human central nervous system (CNS).     

Urological manifestations of Down syndrome

PURPOSE: We identified the urological anomalies seen in patients with Down syndrome. MATERIALS AND METHODS: We reviewed the literature on Down syndrome and its associated genitourinary pathology. RESULTS: Associated defects have been reported throughout the genitourinary tract. The most common renal anomalies seen are renal hypoplasia, obstructive uropathy and glomerular microcysts. Decreased creatinine clearance has also been noted. Developmental anomalies, such as megaureter and vesicoureteral reflux, have been reported. Dysfunctional voiding and urinary retention have been found in these patients. Posterior urethral valves and hypospadias have also been seen. The testicular abnormalities most frequently reported are cryptorchidism, testicular cancer and infertility. CONCLUSIONS: Improved understanding and identification of the various urological anomalies associated with Down syndrome will aid in the care of these patients. In addition, an awareness of perioperative issues will further facilitate a smooth clinical course.     

Fully-automatic microscopic image analysis and measuring of single fiber conduction velocity in the sural nerve of short-term diabetic rats

Contrasting to the usual measurement of nerve conduction velocity, which only determines the conduction of the fastest fibers, single fiber measurement allows the registration of the conduction velocity of different fiber classes. The present experiment was performed to study whether electroneurophysiological and/or morphometrical parameters of group II fibers have changed after shortterm diabetes mellitus. Diabetes was induced in 28-d-old Lewis 1A-rats by administration of 60 mg/KG b.w. Streptozotocin. 60 d later, with the aid of an oscilloscope VKS 22-16 (VUKO Elektronische Ger?te GmbH, Mühlheim) single fiber measurements were performed. Morphometry was carried out on semithin transverse sections of sural nerve with an automatic image analysis system A6471-AMBA/R (Robotron, Dresden). The mean plasma glucose level of diabetic animals was 27.1 +/- 2.7 mmol/l. The mean afferent conduction velocity was significantly reduced in diabetic animals. Furthermore, efferent fibers could be verified in sural nerve which showed also reduced conduction velocity in diabetic rats. Morphometry revealed significant reduction of thickness and area of myelin sheaths, whereas area of axons remained unchanged. Electroneurophysiological and morphometrical changes will be discussed with special emphasis to different fiber groups. It is suggested, that primary Schwann cell lesion is responsible for the observed findings.     

Annual conversion to Alzheimer disease among patients with memory complaints attending an outpatient memory clinic: the influence of amnestic mild cognitive impairment and the predictive value of neuropsychological testing

Summary OBJECTIVE: The goals of this study were to determine the annual conversion rate to Alzheimer disease (AD) among patients reporting memory problems, including a subgroup with amnestic mild cognitive impairment (aMCI), and to investigate the predictive value of neurocognitive testing for future dementia. METHODS: A prospective study was carried out in an outpatient memory clinic. One hundred and seven patients underwent a clinical examination and completed a battery of standard cognitive tests at study entry and two years later. The conversion rate to clinically manifested AD two years later was investigated, and sensitivity, specificity, receiver operating characteristics (AUC), positive predictive value and negative predictive value for each neuropsychological test were determined. RESULTS: We found an annual rate of conversion to AD of 6.5% among patients reporting memory decline in the setting of our clinic. Specifically, patients with aMCI had an annual conversion rate of approximately 20%. The annual conversion rate for patients reporting memory problems but showing no memory deficit at memory testing was approximately 3%. Receiver operating characteristics (AUC) of the neuropsychological tests ranged from 0.60 to 0.94. CONCLUSIONS: Patients with aMCI have 8.6-fold higher odds of developing AD compared with patients without evident memory impairment on neuropsychological testing. Although the risk of developing AD among patients without objective memory decline is small, some patients in this group still convert to AD, and therefore, close clinical monitoring of patients is necessary.

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J?hrliche Konversionsrate von Patienten mit Ged?chtnisbeeintr?chtigung zur Alzheimerkrankheit: Der Einfluss von amnestischer MCI und die pr?diktive Aussagekraft der neuropsychologischen Testung

Zusammenfassung ZIEL: Ziel der vorliegenden Studie war die Bestimmung der j?hrlichen Konversionsrate von Patienten mit subjektiver Ged?chtnisbeeintr?chtigung zur Alzheimerkrankheit unter Berücksichtigung der amnestischen Milden Kognitiven St?rung (aMCI). Die Wertigkeit zur Vorhersage der Konversion durch einzelne neuropsychologische Testverfahren wurde ebenfalls untersucht. METHODIK: Im Rahmen einer Ged?chtnisambulanz wurde eine prospektive Studie durchgeführt. 107 Patienten wurden in die Studie inkludiert. Alle Patienten durchliefen eine neurologische und eine neuropsychologische Untersuchung am Beginn der Studie und nach zwei Jahren am Ende der Studie. Einerseits wurde die Konversionsrate zur Alzheimerkrankheit untersucht, und anderseits wurden einige Kennwerte der Kriteriumsvalidit?t (Sensitivit?t, Spezifit?t, Receiver Operating Characteristics [AUC], Positive Predictive Value, Negative Predictive Value) einzelner neuropsychologischer Testverfahren zur Vorhersage der Alzheimerkrankheit bestimmt. RESULTAT: Wir fanden eine j?hrliche Konversionsrate von 6,5 % für Patienten, die eine Beeintr?chtigung der Ged?chtnisfunktionen berichteten. Patienten mit aMCI hatten eine j?hrliche Konversionsrate von ungef?hr 20 %. Die j?hrliche Konversionsrate von Patienten mit subjektiver Ged?chtnisbeeintr?chtigung ohne testpsychologisch nachweisbare Ged?chtnist?rung lag bei ungef?hr 3 %. Receiver operating characteristics (AUC) für einzelne neuropsychologische Verfahren lagen zwischen 0,60 und 0,94. KONKLUSION: Patienten mit aMCI haben, im Vergleich zu Patienten ohne neuropsychologisch fassbare Ged?chtnisst?rung, eine 8,6-fache Wahrscheinlichkeit, innerhalb von zwei Jahren eine klinisch manifeste Alzheimerkrankheit zu entwickeln. Obwohl die Wahrscheinlichkeit für Patienten ohne neuropsychologisch fassbare Ged?chtnisst?rung, innerhalb von zwei Jahren eine Alzheimerkrankheit zu entwickeln, gering ist, konvertieren einige wenige Patienten doch zur Alzheimerkrankheit. Engmaschige Kontrolluntersuchungen sind deshalb notwendig.

     

Conduction velocities and nerve fibre diameters of touch, pain, urinary bladder and anal canal afferents and alpha and gamma-motoneurons in human dorsal sacral roots

1. Single action potentials were recorded extracellularly at 2 sites from human sacral dorsal nerve roots, and their conduction time measured. Conduction velocity frequency distribution histograms were constructed from afferent and efferent nerve fibres. Conduction velocity distribution peaks could be identified from afferents of mechanoreceptors of the skin, the bladder, the anal canal, of stretch and flow receptors of the urinary bladder, from spindle afferents and from the 3 alpha (extrafusal) and 3 gamma-motoneuron (intrafusal) classes. The electrophysiologically measured roots were removed and morphometrically analysed. Nerve fibre diameter frequency distribution histograms were constructed with respect to 3 myelin sheath thickness ranges. Nerve fibre diameter distribution peaks could partly be correlated to the corresponding conduction velocity distribution peaks. 2. Identified nerve fibre classes, characterized by their group peak values of conduction velocity and fibre diameter were at about 36 degrees C (age 30 years): Spindle afferents: SP1 (60 msec-1/13.2 microns) SP2 (50/12.0?); touch afferents: TO (49 msec-1/13.0 microns), T1 (44/11.2), T2 (39/10.1), T3 (31/9.1), T4 (20/8.3); pain afferents: P (13 msec-1/?); mucosa touch afferents from bladder and anal canal: M (12.5 msec-1/?); bladder afferents from stretch receptors measuring probably mural tension: S1 (42.5 msec-1/?), ST (38/?) and from flow receptors: S2 (12.5/?); alpha-motoneurons: alpha 1 (60 msec-1/13.1 microns) [FF], alpha 11 (?/12.0) [F (int)], alpha 2 (50/10.2) [FR], alpha 3 (37/8.3) [S]; gamma-motoneurons: gamma beta (27 msec-1/7.2 microns), gamma 1 (20/6.7), gamma 2 (15/6.2). 3. Because of the strong temperature dependence of the conduction velocities a calibration of the structure of the velocities, which was almost independent of temperature, is defined by the condition that the alpha 2-motoneurons have the same peak conduction velocity then the secondary spindle afferents (SP2); the T1 touch afferents have about 10% lower velocity values. 4. Touch afferents and alpha-motoneurons had a different velocity-diameter relation, which indicated differences in the myelin sheath thickness and/or membrane properties. The conduction velocities of the touch afferents were more temperature-dependent than those of the alpha-motoneurons. Within the classes of touch afferents and alpha-motoneurons the temperature dependence increased towards smaller class peak values. 5. Through the use of action potential wave form comparisons it was possible to identify action potentials from single nerve fibres in each class of touch afferents (T0 to T4). Activity patterns of single touch units could partly be analysed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Surface EMG- and coordination dynamics measurements-assisted cerebellar diagnosis in a patient with cerebellar injury

Cerebellar diagnostic was performed in a patient who had suffered severe cerebellar injury, using kinesiologic (coordination dynamics) and electrophysiologic (surface EMG (sEMG)) means. Since the right cerebellum had been completely destroyed, significant coordination problems (especially on the right side) were expected to be found in addition to balance problems. As compared to a healthy person, coordination between arms and legs was 80% up to 300% worse. Unexpectedly, no pronounced impairment of coordination of the right arm and right leg was found (with respect to the remaining limbs) as a result of the lost right cerebellum. The values of coordination dynamics measured for the right arm and the right leg for exercising in the forward and backward direction were as good as or even better than those obtained for the left side. However, sEMG disclosed a strong impairment of antagonistic muscle activation (spinocerebellum) between the tibialis anterior and the gastrocnemius muscles on the right side upon exercising the legs only on the special coordination dynamics therapy device (similar to a stationary bicycle). The muscles of the right-sided leg worked worse than those of the left-sided leg. But upon exercising both legs and arms on the special device (more integratively), the antagonistic muscle activation improved in the poor right leg by 36% in the short-term memory but not in the good left leg (symmetry improvement). These kinesiological and electrophysiological measurements show that there was no clear ipsilateral correlation between the cerebellum and the laterality of body functions. For different kinds of supported walking sEMG motor programs worsened with the reduction of the support. Probably the damaged vestibulocerebellum could not sufficiently coordinate balance any more with walking When swinging and jumping on the springboard, sEMG motor programs were best for jumping in anti-phase, where maybe more inhibition is activated. It is concluded that coordination measurements and sEMG are powerful tools to evaluate the outcome of cerebellar injury and to provide a diagnostic tool to quantify improvements in the CNS functioning as a result of the coordination dynamics therapy.     

Symmetry diagnosis and treatment in coordination dynamics therapy

Forward-backward movement symmetry of the human CNS was investigated through pattern change during exercising on a special coordination dynamics therapy and recording device in the forward and backward direction. A mirror-image symmetry shift was found in a patient with cerebellar injury for the attractor patterns (movement patterns with the highest temporal stability) for exercising on the special coordination dynamics therapy device in forward and backward direction, with respect to pace and trot gait coordinations. Symmetry diagnosis and symmetry treatment are of importance in CNS repair because of the learning transfer to the movement symmetry counterpart: training of backward walking improves forward walking The theoretical and practical basis of Schalow Coordination Dynamics Therapy is given in the Method section including symmetry considerations with respect to CNS self-organization.