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Biomedical subjects

J H Koelman

Publications and source records attributed to J H Koelman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Electromyography and recovery of the blink reflex in involuntary eyelid closure: a comparative study.

Electromyographic (EMG) activity of orbicularis oculi and levator palpebrae muscles was recorded to study the origin of involuntary eyelid closure in 33 patients. The evoked blink reflex in all patients and in 23 controls was also studied. To examine the excitability of facial motoneurons and bulbar interneurons in individual patients and to compare the results with EMG findings, R1 and R2 recovery indices were calculated in all subjects, as the average of recovery values at 0.5, 0.3, and 0.21 second interstimulus intervals. Based on EMG patterns, the patients were divided into three subclasses: EMG subclass 1, 10 patients with involuntary discharges solely in orbicularis oculi muscle; EMG subclass 2, 20 patients with involuntary discharges in orbicularis oculi and either involuntary levator palpebrae inhibition or a disturbed reciprocal innervation between orbicularis oculi and levator palpebrae; EMG subclass 3, three patients who did not have blepharospasm, but had involuntary levator palpebrae inhibition in association with a basal ganglia disease. The total patient group showed an enhanced recovery of both R1 and R2 components compared with controls. Although 30 out of 33 patients had blepharospasm (EMG subclasses 1 and 2), R1 recovery index was normal in 64% and R2 recovery index was normal in 54%. Patients with an abnormal R2 recovery index had an abnormal R1 recovery index significantly more often. All patients from EMG subclass 1 had an abnormal R2 recovery index, whereas all patients from EMG subclass 3 had normal recovery indices for both R1 and R2 responses. Seventy five per cent of the patients from EMG subclass 2 had normal recovery indices. The results provide further evidence that physiologically blepharospasm is not a homogeneous disease entity, and indicate that different pathophysiological mechanisms at the suprasegmental, or segmental level, or both are involved.

Adult↗
PubMed1995

Motor neuron disease (amyotrophic lateral sclerosis) arising from longstanding primary lateral sclerosis.

Three men were initially diagnosed as having primary lateral sclerosis (PLS), but eventually developed amyotrophic lateral sclerosis (ALS) after 7.5, 9, and at least 27 years. Non-familial ALS and PLS might be different manifestations of a single disease or constitute completely distinct entities. The clinical diagnosis of PLS predicts a median survival that is four to five times longer than in ALS.

Adult↗
PubMed1995

Pretarsal application of botulinum toxin for treatment of blepharospasm.

The response to botulinum toxin type A was compared after two injection techniques in 45 patients with blepharospasm. Initially, patients were treated according to a triple injection technique; two injections into the upper eyelid and one injection into the lower eyelid. Subsequently, without altering the dose, the same patient group received two further injections into the pretarsal portion of the orbicularis oculi muscle of the upper lid. Triple injections were given in 227 treatments, of which 81% were successful. Mean duration of benefit was 8.5 weeks. Additional pretarsal injections were given in 183 treatment sessions. The number of successful treatments significantly increased, to 95% (P < 0.001), and the mean duration of benefit increased to 12.5 weeks (P < 0.001). Ptosis occurred significantly less often after pretarsal injections (P < 0.01). Patients with combined blepharospasm and involuntary levator palpebrae inhibition responded better to the pretarsal injection technique.

Adult↗
PubMed1995

Dopa-responsive dystonia and normalization of soleus H-reflex test results with treatment.

We studied the ratio of the maximal H-reflex to maximal direct muscle potential (H/M ratio), late facilitation and late inhibition in the recovery curve, and vibratory inhibition of the soleus H-reflex in three consecutive patients with hereditary dopa-responsive dystonia, before and during treatment with levodopa. In one patient, we repeated the H-reflex tests twice after withdrawal of levodopa. The results were compared with those in a group of 48 healthy subjects. In the patients before treatment, the soleus H-reflex recovery curve showed increased late facilitation and depressed late inhibition, reflecting alterations in postsynaptic interneuronal activity. Vibratory inhibition, predominantly reflecting presynaptic inhibitory action, was depressed. Normalization of these test results occurred during levodopa treatment, concurrent with a clear clinical response. The H/M ratio, reflecting the excitability state of the motoneuron pool, was similar during and without levodopa treatment. In the one patient tested after levodopa withdrawal, enhancement of late facilitation and decrease of vibratory inhibition paralleled the reoccurrence of dystonia most clearly. Since soleus H-reflex tests mainly reflect mechanisms operating at the spinal level, spinal aminergic or dopaminergic systems are probably involved in dopa-responsive dystonia.

Adult↗
PubMed1995

Motor persistence of orbicularis oculi muscle in eyelid-opening disorders.

We describe clinical and EMG findings in three patients with an inability to reopen the eyes after voluntary closure of the eyelids. Synchronous EMG recording from the levator palpebrae (LP) and orbicularis oculi (OrbOc) muscles revealed that after voluntary closure of the eyelids and upon the command to open the eyes, all three patients were unable to inhibit the "voluntary" contraction of the OrbOc muscles, while on clinical examination there was no evidence of ongoing OrbOc muscle contraction. This "motor persistence" was restricted predominantly to the pretarsal portion of the OrbOc. In one patient, it occurred as an isolated abnormality of the eyelid movement and was recorded as an additional EMG abnormality in two patients with blepharospasm and involuntary LP inhibition. Clinical examination alone cannot differentiate this type of disorder of supranuclear control of eyelid movement from involuntary LP inhibition; simultaneous EMG recording from the LP and OrbOc muscles is required. Injection of botulinum toxin into the pretarsal portion of OrbOc muscles is helpful.

Aged↗
PubMed1994

Clinical and electromyographic features of levator palpebrae superioris muscle dysfunction in involuntary eyelid closure.

We report on five patients with involuntary eyelid closure, diagnosed as blepharospasm and referred to use for treatment with botulinum A toxin. Synchronous electromyographic (EMG) recording was performed from the levator palpebrae superioris (LP) and the orbicularis oculi (OO) muscles. In the first two cases, EMG registration showed alternating, semirhythmic dystonic activities in both the LP and OO, clinically perceptible as "flickering" of the eyelids. While the eyelids were lowered, one of them also showed involuntary upper eyelid tractions due to dystonic activities of LP. In the third patient, EMG patterns were characterized by a gradual decrease in the level of LP activity, followed by the contraction of OO, which facilitated the return of LP to its tonic activity, termed "postinhibition potentiation" of LP. In the fourth patient, EMG recording showed involuntary inhibition of LP in combination with blepharospasm. Involuntary closure of the eyelids in the fifth patient was caused by short or prolonged periods of involuntary LP inhibition, whereas OO activity remained normal. Our results provide further evidence that LP muscle activities are regulated by burst-tonic motoneurons, and we suggest that these motoneurons, and/or the input signals regulating their activities, can be involved independently in a pathological process. Clinical symptoms are discussed that may be helpful to recognize those cases with LP motor dysfunction, whether or not accompanied by OO activity disorders. Because the term blepharospasm indicates an abnormal motor function of OO, we propose "blepharospasm-plus" to designate those cases with a combined motor dysfunction of LP and OO muscles.

Aged↗
PubMed1994

Normalization of soleus H-reflex recruitment curves in controls and a population of spastic patients.

We examined soleus H-reflex recruitment in 30 controls and 33 patients with spinal cord lesions and spastic spinal paresis. H-reflex gain and threshold were determined from recruitment curves after normalization of stimulus intensity as a multiple of the current for a threshold M-response. Reflex gain was expressed as the mean slope of the H-reflex recruitment curve up to the half-maximal response size. Up to this point the curve follows an almost linear trajectory and will mainly reflect Ia afferent stimulation. This slope had a large variability but was clearly correlated with the H/M ratio. The mean gain was equal in controls and patients. The relation between H- and M-thresholds was expressed as a ratio which had a lower mean value in the patients. Though both H- and M-thresholds may be influenced by peripheral factors, this lower ratio suggests an increase in spinal motoneuron excitability in patients.

Adolescent↗
PubMed1994

Independence of soleus H-reflex tests in control and spastic subjects shown by principal components analysis.

Different soleus H-reflex tests are used in the study of neurophysiological mechanisms of motor control. We studied the interdependence pattern of a number of soleus H-reflex tests, i.e., vibratory inhibition, the ratio of the reflex response to direct muscle potential (H/M ratio) and the homonymous recovery curve with a principal components analysis in 48 healthy controls and 38 patients with signs of the upper motoneuron syndrome. In controls, the analysis showed 3 independent principal components (PCs). Vibratory inhibition and H/M ratio loaded on separate components. Late facilitation and late inhibition variables of the recovery curve loaded on the third component due to the positive correlation (P < 0.001) between these variables. In spastic patients the analysis identified 4 independent PCs corresponding with vibratory inhibition, H/M ratio, late facilitation and late inhibition variables, respectively. The findings suggest that the mutual independence of the different soleus H-reflex tests in patients with the upper motoneuron syndrome has retained the control situation to a large extent.

Adolescent↗
PubMed1994

Abnormal eye movements in blepharospasm and involuntary levator palpebrae inhibition. Clinical and pathophysiological considerations.

We report on four patients with involuntary eyelid closure and eye movement disorders. Three were healthy until the onset of their illness and one had a mild generalized choreoathetosis and dystonia due to kernicterus. Electromyographic recording revealed solely blepharospasm in two patients and blepharospasm in combination with involuntary levator palpebrae inhibition in the other two. The eye movement abnormalities were clinically characterized by inability to fix gaze and short or prolonged episodes of uncontrollable eye deviations accompanied, in two patients, by diplopia in horizontal or vertical directions. These episodes occurred independently of a disorder of eyelid movement. Eye movement recordings with a double magnetic induction technique showed saccadic intrusions in horizontal directions. They consisted of highly frequent square wave jerks in three and sporadic macro-square wave jerks in two patients. There were also episodes of extraocular muscle dystonia, commonly known as oculogyric crises, resulting in involuntary upward eye deviation in all patients and lateral deviation in three patients. In one patient, nasal-ward deviations were sometimes restricted to one eye. We conclude that these abnormal eye movements do not necessarily point to a symptomatic form of dystonia and that they may limit the beneficial effect of botulinum toxin or surgical intervention in the therapeutic management of involuntary eyelid closure. We suggest that either basal ganglia, especially substantia nigra pars reticularis and the brainstem structures, especially the paramedian pontine reticular formation, or both, may be involved in the pathogenesis of these abnormal movements.

Adult↗
PubMed1993

Posterior tibial nerve somatosensory evoked potentials in slowly progressive spastic paraplegia: a comparative study with clinical signs.

Clinical and neurophysiological examinations were performed on seven patients with hereditary spastic paraplegia and on eight patients with primary lateral sclerosis. The results were compared with those obtained from a group of 39 control subjects. Prolonged latency times and decreased amplitudes of the posterior tibial nerve (PTN) somatosensory evoked potentials (SEPs) were found in the majority of the patients. The SEP changes occurred without sensory impairment or with loss of vibration sense only. There was no significant relation between the PTN SEP abnormalities and the severity of pyramidal signs for the whole patient group, nor longitudinally for the individual subjects. Analyses of PTN SEPs in patients suffering from slowly progressive spastic paraplegia (SP), therefore, seem to be a method to indicate a feature of spinal cord dysfunction that is not related to the severity of clinical signs. Considering the neuropathology of the spinal cord in SP patients, we furthermore argue that the ascending spinal pathway involved in conducting impulses for PTN SEPs probably uses other routes as well as the funiculus gracilis.

Adolescent↗
PubMed1993

Posterior tibial and sural nerve somatosensory evoked potentials: a study in spastic paraparesis and spinal cord lesions.

In two groups of patients posterior tibial nerve (PTN) and sural nerve (SN) somatosensory evoked potentials (SEPs) were compared to each other and related to classified neurological signs. Group A consisted of 7 patients with hereditary spastic paraparesis (HSP) and 8 with primary lateral sclerosis (PLS), with solely or primarily motor deficits. Group B consisted of 12 patients with different spinal cord diseases causing variable mixed sensory and motor impairments. Normal values were derived from 39 controls. A clear trend towards more frequently prolonged PTN SEP than SN SEP latencies was found in both groups and appears to make PTN SEPs more useful for clinical application than SN SEPs. No significant differences were found in SEP abnormalities when the two patient groups were compared to each other. No relationships were found between SEP abnormalities and spasticity, weakness or any single sensory modality, making the two SEPs questionable as a quantitative test for neurological deficits in our patients.

Adolescent↗
PubMed1993

Soleus H-reflex tests and clinical signs of the upper motor neuron syndrome.

Soleus H-reflex tests are used for elucidating pathophysiological mechanisms in motor control. The cumulative vibratory inhibition of the soleus H-reflex, the ratio of the reflex to direct muscle potential (H to M ratio) and the recovery curve of the soleus H-reflex were studied in 38 patients with varying signs of the upper motor neuron syndrome for a possible relation with clinical features. The results were compared with those obtained from a group of healthy volunteers. The magnitude of vibratory inhibition decreased with increase of hypertonia. The H to M ratio increased as the activity of the tendon reflex was enhanced and correlated to a lesser degree with muscle tone. Both the H to M ratio and late facilitation of the soleus H-reflex recovery curve were elevated in clonus. The findings suggest that alterations in the results of soleus H-reflex tests relate to specific clinical features of the upper motor neuron syndrome. Possible pathophysiological implications are discussed.

Adolescent↗
PubMed1990

Effects of brainstem lesions on the masseter inhibitory reflex. Functional mechanisms of reflex pathways.

The masseter inhibitory reflex (MIR) was investigated in 16 patients with localized brainstem lesions involving the trigeminal system. The MIR consists of two phases of EMG silence (S1 and S2) evoked by stimulation of the mental nerve during maximal clenching of the teeth. The extent of the lesions was assessed by neurological examination, nuclear magnetic resonance imaging (MRI), and recording of trigeminal reflexes with known paths (jaw jerk and blink reflex). The MIR appeared to be abnormal in lesions involving the pontine tegmentum, from the pontomedullary junction to midpons, and some lesions selectively affected one component of the MIR, proving that S1 and S2 are relayed by independent circuits. The results indicate that afferent fibres for S1, which reach the pons via the trigeminal sensory root, enter the ipsilateral trigeminal spinal tract and terminate at the level of the midpons; impulses are then relayed by interneurons to the ipsilateral and contralateral trigeminal motor nuclei. The afferent fibres for S2 follow a similar path, but descend to the pontomedullary junction; at this level impulses are conducted along bilateral interneuronal paths, which probably ascend through the lateral reticular formation, before connecting with the trigeminal motor nucleus on either side. Analysis of MIR recordings can be of particular value because brainstem inhibitory reflexes cannot be tested by clinical examination.

Adult↗
PubMed1989

Cumulative vibratory indices and the H/M ratio of the soleus H-reflex: a quantitative study in control and spastic subjects.

Suppression of the soleus (Sol) H-reflex recruitment curve by Achilles tendon vibration and the ratio of maximum Sol H-reflex (Hmax) to maximum M-response (H/M ratio) have been studied by means of computer processing on the basis of peak-to-peak (P-P) and area values in 46 controls and in 16 spastic patients. The 'classical' vibratory index (VI) has been compared with a new cumulative VI (CVI), which is defined as the quotient of the surface under the recruitment curve obtained with vibration and the one obtained without vibration up to an equal intensity level. Statistical analyses were performed from threshold to 3 different intensity levels. Tendon vibration is found to be less effective at higher intensity levels. Mean values with S.D.s of CVIs at Hmax intensity are significantly lower than those of the 'classical' VIs. VIs increase with age while H/M ratios decline. Stepwise discriminant analyses showed that area CVI at Hmax intensity yielded the best distinction between controls and patients. Additional differential contribution is obtained by P-P H/M ratio. A canonic variable derived from these two variables correctly classified 44 out of 46 controls and 15 out of 16 patients. The methods presented improve the specificity of the quantitative neurophysiological measure of spasticity by means of Sol H-reflex recordings.

Achilles Tendon↗
PubMed1987

Drug therapy in continuous ambulatory peritoneal dialysis patients.

Transport of solutes across the peritoneal membrane in continuous ambulatory peritoneal dialysis (CAPD) is determined by patient-related factors (concentration gradient, membrane surface area, blood flow and membrane permeability) and by drug-related factors (charge on the molecule, protein binding, molecular weight, lipophilicity). On the basis of the chemical properties of a drug a prediction of the peritoneal clearance rate in CAPD patients is given, by the formula CLCAPD = 75 square root free fraction/molecular weight. The implications of this formula are discussed. It is concluded that usually it is not necessary to change the dose as compared with end-stage renal disease patients who are not treated with CAPD.

Drug Therapy↗