Electrophysiological brainstem testing in the diagnosis of reversible brainstem ischemia.

The aim of this study was to evaluate the sensitivity of multimodal electrophysiological brainstem testing in the diagnosis of clinically suspected reversible ischemic deficits of the brainstem compared with diffusion weighted MR imaging. We investigated 158 consecutive patients presenting with signs of acute brainstem dysfunction. Serial electrophysiological brainstem tests including masseter reflex, blink reflex, masseter inhibitory reflex, AEP, MEP, EOG and the oculoauricular phenomenon were applied. In 14 of the 158 patients neurological deficits resolved in less than 24 hours, which was suggestive of a transitory ischemic attack (TIA), 19 patients had brainstem signs for more than 24 h…

Localization of emotional and volitional facial paresis.

Emotional facial paresis is characterized by impaired activation of face muscles with emotion but normal voluntary activation. We report seven patients with this sign. Their lesions involved the frontal lobe white matter, the striatocapsular territory, the anterolateral thalamus and insula, the posterior thalamus and operculum, and the mesial temporal lobe and insula each in one patient, and the posterior thalamus in two patients. Volitional facial paresis affects facial movements with voluntary effort, sparing activation on emotion. We report four such patients, with lesions involving the motor cortex in one and the pyramidal tract in the cerebral hemisphere in three.

Abduction saccades in unilateral internuclear ophthalmoplegia

Horizontal eye movements were investigated in 60 consecutive patients with unilateral internuclear ophthalmoplegia utilizing direct current electrooculography. In nine patients additional conjugated slowing of ipsiversive saccades indicated the diagnosis of a one-and-a-half syndrome. Slowing of abduction saccades was bilateral in two patients and unilateral in 20 (ipsilateral to the MLF lesion in 17 patients and contralateral in three). Slowing of abduction saccades was attributed to impaired inhibition of the tonic resting activity of the antagonistic medial rectus muscle. On the eye contralateral to the lesion 70% of the patients had abduction nystagmus and 66.7% hy permetric abduction sa…

Third nerve palsy as the sole manifestation of midbrain ischemia

Thirty-seven patients with risk factors for the development of cerebrovascular diseases had sudden onset isolated third nerve palsy and abnormal masseter reflex and/or electro-oculographic findings indicating a causative midbrain lesion. Improvement or recovery of the third nerve palsies was accompanied by improvement or recovery of the abnormal electrophysiologic findings pointing to their functional significance. Magnetic resonance imaging (MRI) in 29 of these patients demonstrated corresponding ischemic midbrain lesions in eight, ipsilateral in five patients, bilateral in three. In another three patients with MRI proven midbrain lesions (ipsilateral in two, bilateral in one) electrophysi…

Persistent unilateral tibialis anterior muscle hypertrophy with complex repetitive discharges and myalgia

Unilateral enlargement of the tibialis anterior muscle associated with complex repetitive discharges occurred over several months in two patients and was preceded by pain and numbness in the lower leg. Neuroradiologic investigations excluded a compressive radiculopathy, but pharmacologic and neurophysiologic studies suggested a neurogenic basis for the muscle hypertrophy. Botulinum toxin A injection into the hypertrophied muscles led to a decreased muscle volume and cessation of muscle pain.

The pterygoid reflex in man and its clinical application

A technique for eliciting and recording the stretch reflex (R) of the medial pterygoid muscle (Pter) is described. The latency was 6.9 ± 0.43 ms in 23 healthy volunteers (mean age 23.7 years) showing a side-to-side difference of 0.29 ± 0.21 ms. The PterR latencies were little shorter and side-to-side difference little greater than of the masseter reflex. Observations in 5 selected patients with small brainstem lesions suggest that the neurons of the PterR afferents form a cluster within the caudal portion of the trigeminal mesencephalic nucleus. Testing the masseter and pterygoid reflexes provides a more precise localization of small ponto-mesencephalic lesions. © 1992 John Wiley & Sons, In…

Facial myokymia and contraction persisting 20 years: a case of pontine glioma.

Acquired monocular elevation paresis. An asymmetric upgaze palsy.

Five patients with acquired monocular elevation paresis were investigated using direct current electrooculography. With recovery, upward saccade velocities significantly increased in both eyes in all patients. The gain of upward-following eye movements significantly increased in the paretic eye of all patients and in the opposite eye of four patients. These findings are interpreted in terms of an asymmetric upgaze palsy which clinically presented as monocular elevation paresis in the more severely affected eye. A brainstem lesion contralateral to monocular elevation paresis was suggested in four patients by contralateral Horner's syndrome and contralateral abduction paresis, each in one pat…

Latency and amplitude variability in serial median nerve SEP recordings

Abstract Objectives : Intra-individual variability of SEP parameters was investigated by serial SEP recordings. Methods : Median nerve SEP of 53 normal subjects (mean age 25.5±2.7 years) were evaluated. Recordings were repeated 1 week, 2 weeks, and 6 months after the initial recording. Results : Mean values of latencies from right median nerve stimulation were slightly longer (+0.1 ms) as compared to the left. The intra-individual (within stimulation side) variance did not depend on the time interval between recordings. The total within-stimulation-side variance of latencies was 0.056 ms 2 for N20 (C 3/4 ′ vs. F z ), 0.070 ms 2 for N13 (C 7 vs. F z ), 0.048 ms 2 for N10 (Erb's point vs. F z…

Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis

The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…

Two cases of adynamia episodica hereditaria: In vitro investigation of muscle cell membrane and contraction parameters

Membrane potentials, current-voltage relationships, and contractile parameters were studied in intact muscle cell bundles obtained from two patients with adynamia episodica hereditaria. In a normal extracellular medium, the cell membranes had resting potentials of about -80 mV and their current-voltage relationships were not significantly different from control curves. In contrast to normal muscles the afflicted cells were paralyzed in a medium having 6-10 mmol/liter potassium. The mechanisms of paralysis in the two specimens were different from each other. Many fibers from one patient were spontaneously active even in normal solution. In high potassium solution spontaneous activity was inc…

Electrophysiology of sensory neuropathies

In sensory neuropathy maximal conduction velocity is a crude measure. Variations up to 10 m/s have to be considered normal. The relation to clinical impairment is poor in either axonal/neuronal lesions or demyelination as indicated by a small normal latency and a delayed broad polyphasic nerve action potential (NAP), respectively. Conduction block evaluated on NAP changes has not yet been established. Mild disorder of impulse conduction may be disclosed by evaluating a) conduction along long nerve segments studying the H-reflex or SSEP, b) late components of the averaged NAP which make > 10% of the main deflection, c) velocities of slow conducting fibers utilizing the collision technique or…

Cerebellar speech representation: lesion topography in dysarthria as derived from cerebellar ischemia and functional magnetic resonance imaging.

Background Lesion topography and the pathophysiological background of dysarthria due to focal cerebellar lesions have not yet been fully clarified. Objectives To investigate the lesion topography of dysarthria due to cerebellar ischemia and evaluate brainstem functions. Design Case studies. Patients Eighteen right-handed patients with sudden-onset dysarthria and cerebellar ischemia with and without brainstem involvement and 19 healthy, right-handed, monolingual, German-speaking volunteers. Methods In patients, we used multimodal electrophysiologic techniques to investigate brainstem functions. Functional magnetic resonance imaging (MRI) was performed in the 19 healthy volunteers. Activation…

Isometric muscle contractions after double pulse stimulation. comparison of healthy subjects and patients with myotonic dystrophy.

Isometric contractions of the adductor pollicis muscle were studied in healthy subjects and patients with myotonic dystrophy after single and double stimuli of the ulnar nerve using a wide range of interstimulus intervals (ISI, 0.4-180 ms). In healthy subjects, the force contributed by a second stimulus was greater than the single twitch force being maximal (mean + 140%) at 12-ms ISI. In myotonic dystrophy, the force contributed by the second stimulus was (relative to a reduced twitch amplitude) increased (mean + 204%) with a maximum at 4.8-ms ISI. An abnormal increase of force was only recorded if the single twitch force was clearly reduced. The absolute refractory period of muscle contrac…

Impaired refractory periods of peripheral sensory nerves in multiple sclerosis.

Maximum conduction velocity and relative refractory period (RRP) of median nerve sensory fibers were studied in 36 patients diagnosed as having multiple sclerosis (MS) and in 31 controls. Maximum conduction velocity did not differ in the two groups, but the RRP was significantly prolonged in MS patients. Increased RRP is observed mainly when peripheral nerve myelin is abnormal or damaged. Our findings support the assumption that peripheral nerve myelinated fibers are usually involved in MS.

Slowed abduction saccades in bilateral internuclear ophthalmoplegia

Horizontal eye movements were investigated in 65 patients with bilateral internuclear ophthalmoplegia utilizing direct current electro-oculography. Abduction saccades were slowed in 35 patients (53.8%), being hypermetric in 65.7% of them. Slowing of abduction saccades is attributed to impaired inhibition of the tonic resting activity of the antagonistic medial rectus muscle. Experimental data indicate that this slowing results from a lesion of an uncrossed connection between the pontine reticular formation and the oculomotor nucleus. The prevalence of hypermetric abduction saccades increased with increasing severity of adduction paresis on the opposite eye. This confirms the view that media…

Pupil-sparing oculomotor palsy as the only clinical sign of an internal carotid artery occlusion

Low-frequency ultrasound induces nonenzymatic thrombolysis in vitro.

To evaluate whether ultrasound, applied over a distance of several centimeters and in the absence of thrombolytic agents, may have a thrombolytic effect on blood clots.Low-frequency (20 kHz) continuous wave ultrasound at different intensity levels (0.15-1.2 W/cm2) and exposure times (5, 10, and 20 minutes) was assessed for its potential to induce thrombolysis of fresh human blood clots. The ultrasound effect was also studied in combination with recombinant tissue-type plasminogen activator-mediated thrombolysis. Experiments were carried out in a flow model in degassed sodium phosphate buffer at 37 degrees C at a distance of 3 cm from the ultrasonic probe to the blood clots. Regardless of ul…

Hypokalemia shortens relative refractory period of peripheral sensory nerves in man

Absolute and relative refractory periods and the sensory conduction velocity of the median and ulnar nerves were determined in six patients suffering from hypokalemia of various origins. Nerve impulse conduction and the absolute refractory period remained normal, but the relative refractory period was shortened to 1.7 to 2.6 ms at serum K+ levels from 1.6 to 2.9 mval/l. As compared with normal values this decrease was statistically significant.

Dysarthria and lacunar stroke

We investigated the supranuclear tracts involved in speech production in 8 patients with dysarthria associated with a single lacunar stroke.Magnetic resonance imaging revealed the lesion site in 7 out of 8 patients. We tested corticobulbar tract function using transcranial magnetic stimulation and demonstrated impairment of the corticolingual projections in all the patients and in 5 patients impairment of the corticofacial projections. Sensory function in the oral cavity was impaired in 1 out of 8 patients.99m Tc hexamethyl-propylene amine oxime-single-photon emission computerized tomography (HMPAO-SPECT) imaging, performed in 5 patients, showed cerebellar diaschisis in 1, suggesting additi…

Diabetic 3rd nerve palsy: evidence for a mesencephalic lesion.

Eleven consecutive adult chronic diabetic patients presented with an isolated 3rd nerve palsy (8 with pupillary sparing) of which 10 had abnormal ipsilateral or bilateral masseter reflexes (MassR). Three patients had an MRI lesion in the ipsilateral oculomotor fasciculus and 3 had subsequent mild brainstem signs. An additional 13 patients with Weber's syndrome had similar ipsilateral or bilateral MassR abnormalities, while 7 patients with 3rd nerve palsies on a known extra-axial basis had none. The findings suggest that an isolated diabetic 3rd nerve palsy, with or without pupillary sparing, is much more likely on the basis of a focal mesencephalic infarct than a peripheral nerve lesion.

Isolated superior oblique palsies with electrophysiologically documented brainstem lesions

Over a 13.5-year period, we observed 10 patients with isolated superior oblique palsies in whom electrophysiological abnormalities indicated brainstem lesions. In 7 patients unilateral masseter reflex abnormalities were seen, and were located on the side of the superior oblique palsy in 2 patients and on the opposite side in 5 patients. Two patients had slowed gain of following eye movements to the side contralateral to the superior oblique palsy. Slowed adduction saccades in the eye contralateral to the superior oblique palsy were seen in 1 patient. Clinical improvement was frequently (in 7 of 10 patients) associated with improvement or normalization of electrophysiologic findings. Magneti…

The chemiluminescence activity of peripheral blood mononuclear cells during acute experimental allergic encephalomyelitis

The spontaneous chemiluminescence activity (CL-A) of peripheral mononuclear cells (MNC) was examined in Lewis rats with acute experimental allergic encephalomyelitis (EAE), compared to rats immunized with complete adjuvant (n = 11) and healthy animals (n = 16). In rats with EAE, CL-A increased sharply 8-9 days after immunization (3420 +/- 3124 counts/10 s, n = 16) at the time of flattening of the weight curve. This CL-A peak was compared to that of animals immunized with complete adjuvant: 765 +/- 441 counts/10 s (P = 0.01) and healthy rats: 450 +/- 172 counts/10 s (P = 0.0001). After this initial peak in EAE rats, CL-A decreased almost to normal values when animals lost weight (746 +/- 251…

Seventh nerve palsies may be the only clinical sign of small pontine infarctions in diabetic and hypertensive patients

Backgroud: Small brainstem infarctions are increasingly recognized as a cause of isolated ocular motor and vestibular nerve palsies in diabetic and/or hypertensive patients. This raises the question whether there are also isolated 7th nerve palsies due to pontine infarctions in patients with such risk factors for the development of cerebrovascular diseases. Methods: Over an 11-year-period, we retrospectively identified 10 diabetic and/or hypertensive patients with isolated 7th nerve palsies and electrophysiological abnormalities indicating pontine dysfunction. All patients had examinations of masseter and blink reflexes, brainstem auditory evoked potentials, direct current electro-oculograp…

Midbrain vs. pontine medial longitudinal fasciculus lesions: The utilization of masseter and blink reflexes

Masseter (MR) and blink reflexes (BL) were investigated in 51 patients with internuclear ophthalmoplegia (INO) due to multiple sclerosis (28) and lacunar infarction (23). The MR was abnormal in 20 of 23 cases with bilateral INO and in 21 of 28 with unilateral INO. The R1 component of the BL (BL-R1) was abnormal in 7 of 23 patients with bilateral INO and 10 of 28 with unilateral INO. Combined MR and BL-R1 changes occurred in 8 of 28 cases with unilateral INO and 7 of 23 with bilateral INO. The findings provide evidence for a rostral/caudal localization of lesions within the medial longitudinal fasciculus causing INO on the basis of MR and BL-R1 abnormalities. An abnormality limited to MR sug…

Pain-evoked blink reflex

The electrically evoked blink reflex (BR) consists of an ipsilateral R1 component (R1) at 11 ms and two bilateral components R2 at 33 ms and R3 at 83 ms. It is still unclear whether the R2 is mediated by activation of tactile or nociceptive afferents. For testing the nociceptive hypothesis, nociceptors of the supraorbital nerve were selectively activated by infrared laser stimuli in 10 subjects. Only painful laser stimuli evoked a bilateral early polyphasic BR response (LR2) at 71 ms. Stimulation of infraorbital and mental nerve dermatomes was equally effective. A late bilateral reflex response at 130 ms was occasionally observed. Regarding the nociceptor activation time of about 40 ms, ons…

Evaluation of carpal tunnel syndrome in patients with polyneuropathy

The difference between the median nerve latency to the second lumbrical muscle and the ulnar nerve latency to the second interosseous muscle (L-I DIFF) was tested in a prospective study to discriminate whether prolonged distal motor latency of the median nerve in patients with polyneuropathy (PNP) reflects an additional carpal tunnel syndrome (CTS). We investigated 92 patients (107 hands) with CTS, 30 patients (34 hands) with PNP, 22 patients (27 hands) with CTS and coexisting PNP (PNP+CTS), and 77 controls (87 hands). L-I DIFF was significantly prolonged in both the CTS and PNP+CTS patients as compared to PNP patients and controls. It proved to be the most specific test to differentiate be…

Cortico-bulbar fibers to orofacial muscles: recordings with enoral surface electrodes.

A new recording technique was developed to eliminate current problems on recording transcranial evoked facial muscle responses. A fork-shaped device equipped with 2 pairs of Ag/AgCl-electrodes was inserted enorally at the buccinator muscle level. Advantages offered by this method comprise clearly defined negative deflection of the compound muscle action potential, lack of relevant volume conduction from adjacent muscles, reliability of amplitude criteria, absence of interfering stimulus artifacts, easy achievement of preactivation, and noninvasive recording by surface electrodes. In 43 healthy subjects transcranial magnetic stimulation evoked contralateral responses at a mean latency and me…

Symmetrical Infarction of the Cervical Spinal Cord Due to Spontaneous Bilateral Vertebral Artery Dissection

To the Editor: Vertebral artery (VA) dissection is a well-known cause of vertebrobasilar ischemia in young people and may be due to preceding chiropractic maneuvers, cystic medial necrosis, mucopolysaccharidosis and reticular fiber diseases, vasculitis,1 2 or a yet-unknown arteriopathy.3 Common findings in VA dissection are unilateral or bilateral neck pain associated with cerebellar and brain stem (usually medullary) infarctions,2 3 which are rarely associated with clinical signs of spinal cord lesions.4 5 6 Recently, 1 patient each was described with bilateral spinal cord infarction7 and Brown-Sequard’s syndrome8 as the sole manifestation of spontaneous unilateral VA dissection. We add an…

Topodiagnostik ischämisch bedingter Dysarthrophonien

In einer prospektiven Studie untersuchetn wir 106 konsekutiv eingeschlossene Patienten mit apoplektiform auftretender Dysarthrophonie aufgrund eines im MRT gesicherten singluaren, nicht raumfordernden Infarkts.

Neurogenic hyperalgesia versus painful hypoalgesia: two distinct mechanisms of neuropathic pain

Patients with sensory disturbances of painful and non-painful character show distinct changes in touch and/or pain sensitivity. The patterns of sensory changes were compared to those of human surrogate models of neuropathic pain to assess the underlying mechanisms. We investigated 30 consecutive in-patients with dysaesthesia of various origins (peripheral, spinal, and brainstem lesions) and 15 healthy subjects. Tactile thresholds were determined with calibrated von Frey hairs (1.1mm). Thresholds and stimulus-response functions for pricking pain were determined with a series of calibrated punctate mechanical stimulators (0.2mm). Allodynia was tested by light stroking with a brush, Q-tip, and…

Impaired neuromuscular transmission during partial inhibition of acetycholinest-erase: The of stimulus-induced antiromic backfiring in the generation of the decrement-increment phenomenon

Neuromuscular transmission was studied in the rat phrenic nerve-hemidiaphragm preparation with acetylcholinesterase (AChE) partially inactivated. Enzyme inhibition resulted in (1) increased single-twitch tension of the diaphragm; (2) compound muscle action potential (CMAP) containing repetitive discharges; (3) stimulus-induced antidromic backfiring (SIAB) seen in the phrenic nerve; and (4) repetitive nerve stimulation (RNS) eliciting a decrement-increment (D-I) phenomenon (i.e., amplitude reduction maximal with the second CMAP). Using a high-calcium and low-magnesium solution, SIAB and the decrement of the second CMAP during RNS were intensified, whereas closely spaced trains and (+)-tubocu…

Granular nuclear inclusion body disease: Fine structure of tibial muscle and sural nerve

Fine granular (hyaline) intranuclear inclusion bodies were found in perivascular cells of a muscle and a sural nerve biopsy from a 32-year-old woman with slowly progressive motor disturbances. The hyaline nuclear inclusion bodies could be distinguished from other intranuclear hyaline inclusions by their granularity, the size of the granules (approximately 5-15 nm), and the positive iron staining reaction. They were not seen in muscle fibers or Schwann cells. Because of these apparently pathognomonic structural features the patient appears to present a condition that has not been described before.

Assessment of brainstem function in Chiari II malformation utilizing brainstem auditory evoked potentials (BAEP), blink reflex and masseter reflex

Brainstem dysfunction was evaluated in 67 patients with myelomeningocele and Chiari II malformation using brainstem auditory evoked potentials (BAEP), blink reflex (BR) and masseter reflex (MR). Signs and symptoms related to Chiari II malformation were observed in 18 patients while 49 patients had normal brainstem findings. BAEP and BR showed a higher sensitivity of brainstem involvement than MR (BAEP=1.0, BR=0.83, MR=0.50). BR, and in particular, MR were of higher accuracy (BR=0.52, MR=0.72) than BAEP (0.39) in separating patients with brainstem signs and symptoms related to Chiari II malformation. We feel that this is due to anatomic and physiologic peculiarities of the brainstem structur…

End-plate dysfunction in acute organophosphate intoxication.

Acute organophosphate intoxication resulting from suicide attempts in 14 patients produced a series of electrophysiologic abnormalities that correlated with the clinical course. Spontaneous repetitive firing of single evoked compound muscle action potentials (CMAP) was the earliest and most sensitive indicator of the acetylcholinesterase inhibition. A decrement of evoked CMAP following repetitive nerve stimulation was the most severe abnormality. At the height of the intoxication no CMAP was evoked after the first few stimuli. The decrement-increment phenomenon occurred only at milder stages of intoxication and its features are characteristic of acetylcholinesterase inhibition. These electr…

Nociceptive masseter inhibitory reflexes evoked by laser radiant heat and electrical stimuli

Electrical stimulation of the mental nerve evokes two suppression periods SP1 and SP2 in masseter muscle activity bilaterally. In order to investigate a possible nociceptive origin of the suppression periods, we compared the reflex responses evoked by electrical stimulation and by selective activation of nociceptors in hairy skin using painful infrared laser stimuli. The SP was elicited during more than 90% maximal voluntary contraction. Thresholds for detection, pain, and SP in the mental nerve area were determined by the method of limits. A suppression period was evoked by laser stimuli in nine of ten subjects bilaterally. The mean onset latency was 46.9 ms, the mean duration 58.9 ms. The…

Mechanisms and predictors of chronic facial pain in lateral medullary infarction

The purpose of this study was to identify clinical predictors and anatomical structures involved in patients with pain after dorsolateral medullary infarction. Eight out of 12 patients (67%) developed poststroke pain within 12 days to 24 months after infarction. The pain occurred in the ipsilateral face (6 patients) and/or the contralateral limbs and trunk (5 patients, 3 of whom also had facial pain). Ipsilateral facial pain was significantly correlated with lower medullary lesions, including those of the spinal trigeminal tract and/or nucleus, as documented by magnetic resonance imaging. The R2 blink reflex component was abnormal only in patients with facial pain. Likewise, pain and temper…

Internalized myofiber capillaries: Observations on their origin and clinical features

Internalized capillaries limited to type 1 muscle fibers were noted in seven patients. They occurred in each case in association with a similar admixture of neurogenic and myopathic features that included atrophic and hypertrophic fibers, internal nuclei, fiber splitting, and endomyseal and perimyseal fibrosis. Internalized capillaries in enlarged type 1 fibers arose from fiber splits on step section study of four patients. They occurred in the gastrocnemius, quadriceps, and soleus muscles from patients with a variety of disorders that included Becker dystrophy, diabetes mellitus and strenuous leg activities, Achilles tendon rupture, and myotonic dystrophy. Exercise-induced myalgias were no…

Isolated cranial nerve palsies in multiple sclerosis

During a 10 year period 24 patients with definite multiple sclerosis with isolated cranial nerve palsies were studied (third and fourth nerve: one patient each, sixth nerve: 12 patients, seventh nerve: three patients, eighth nerve: seven patients), in whom cranial nerve palsies were the presenting sign in 14 and the only clinical sign of an exacerbation in 10 patients. MRI was carried out in 20 patients and substantiated corresponding brainstem lesions in seven patients (third nerve: one patient, sixth nerve: four patients, eighth nerve: two patients). Additional abnormal findings of electro-oculography, or masseter reflex, or blink reflex, or combinations of these were found in 20 patients…

Protective effect of serotonin on migraine attacks

Pontine lesions mimicking acute peripheral vestibulopathy

OBJECTIVES Clinical signs of acute peripheral vestibulopathy (APV) were repeatedly reported with pontine lesions. The clinical relevance of such a mechanism is not known, as most studies were biased by patients with additional clinical signs of brainstem dysfunction. METHODS Masseter reflex (MassR), blink reflex (BlinkR), brainstem auditory evoked potentials (BAEPs), and DC electro-oculography (EOG) were tested in 232 consecutive patients with clinical signs of unilateral APV. RESULTS Forty five of the 232 patients (19.4%) had at least one electrophysiological abnormality suggesting pontine dysfunction mainly due to possible vertebrobasilar ischaemia (22 patients) and multiple sclerosis (ei…

Multiple sclerosis patients show an increased spontaneous activity of their peripheral blood monocytes as measured by chemiluminescence

I has been reported that myelin basic protein (BP) reacts extremely sensitively to peroxide, which is formed when monocytes/macrophages are stimulated to produce a "respiratory burst" (RB). We measured the RB activity by means of chemiluminescence in peripheral blood monocytes/macrophages (MO) of 17 MS patients, 5 patients with a viral infection of the CNS, and 14 control persons. The median of the spontaneous RB activity of MS patients compared with the median of our control group showed a highly significant increase (P = 0.0002). All MS patients examined possessed a clearly increased MO activity. The highest values, however, were found in MS patients in a bout (means = 315%, means = 296%)…

Therapy of Early Poststroke Depression With Venlafaxine: Safety, Tolerability, and Efficacy as Determined in an Open, Uncontrolled Clinical Trial

To the Editor: The development of persistent depressive symptoms is a severe and frequent complication of ischemic or hemorrhagic stroke.1 The etiology of poststroke depression is not well understood. Only few placebo-controlled, double-blind studies have been carried out, all reporting various degrees of superiority of standard antidepressants over placebos.1 2 On the other hand, serious side effects have been reported.3 4 In most of these studies, patients were examined whose stroke had occurred several weeks to several months before the antidepressive therapy was started. Antidepressive therapy in the first weeks after stroke has not yet been attempted in studies. Drug-induced improvemen…

Medullary infarcts may cause ipsilateral masseter reflex abnormalities.

There is a suprasegmental influence on the masseter reflex (MassR) in animals, which is mediated via the fifth nerve spinal nucleus (5SpN). Corresponding data in humans are lacking. Out of 268 prospectively recruited patients with clinical signs of acute brainstem infarctions, we identified 38 with magnetic resonance imaging (MRI)-documented unilateral infarcts caudal to the levels of the fifth nerve motor and main sensory nuclei. All had biplanar T2- and echo planar diffusion-weighted MRI and MassR testing. Five patients (13%) had ipsilateral MassR abnormalities. In all, the infarcts involved the region of the 5SpN. Patients with medullary infarcts involving the region of the 5SpN may thus…

Time course of lesion development in patients with acute brain stem infarction and correlation with NIHSS score.

diffusion weighted magnetic resonance imaging (MRI) is highly sensitive in detecting acute supratentorial cerebral ischemia and Diffusion Weighted Imaging (DWI) lesion size has been shown to correlate strongly with the neurologic deficit in middle cerebral artery territory stroke. However, data concerning infratentorial strokes are rare. We examined the size and evolution of acute brain stem ischemic lesions and their relationship to neurological outcome.brain stem infarctions of 11 patients were analyzed. We performed DWI in all patients and in 7/11 patients within 24 h, T2W sequences within the first 2 weeks (10/11 patients) and follow-up MRI (MR2) within 3-9 months (median 4.8 months) la…

Masseter reflex and blink reflex abnormalities in Chiari II malformation.

Masseter reflex and blink reflex were evaluated in 64 patients with a myelomeningocele and Chiari II malformation. In 46 patients, no brainstem signs or symptoms were present. Brainstem dysfunction related to Chiari II malformation occurred in 18 patients. The masseter reflex was more frequently abnormal in the symptomatic than asymptomatic patients (P = 0.02). Although the blink reflex was similarly affected in the two groups of patients (P > 0.1), it was very sensitive, being abnormal in 83% of symptomatic and 65% of asymptomatic patients. Concomitant abnormality of masseter reflex and the late contralateral blink reflex component (R2c) was almost exclusively found in symptomatic patients…

Somatotopic organization of the corticospinal tract in the human brainstem: a MRI-based mapping analysis.

To investigate the incompletely understood somatotopical organization of the corticospinal tract in the human brainstem, we performed a voxel-based statistical analysis of standardized magnetic resonance scans of 41 prospectively recruited patients with pyramidal tract dysfunction caused by acute brainstem infarction. Motor hemiparesis was rated clinically and by the investigation of motor evoked potentials to arms and legs. Infarction affected the pons in 85% of cases. We found the greatest level of significance of affected brainstem areas between the pontomesencephalic junction and the mid pons. Lesion location was significantly more dorsal in patients with hemiparesis affecting more prox…

A fully automated system for the evaluation of masseter silent periods.

Exteroceptive suppression of masseter muscle activity, 'masseter inhibitory reflex', comprises one or 2 silent periods (SP1 and SP2) interrupting the voluntary activation. The main problem when evaluating exteroceptive suppression is the lack of an objective and precise measure for the onset and end of the silent period which so far has not been overcome by various automated systems. We describe a new fully automated system for determining the onset and end of the masseter silent period. The decision approach is essentially based upon deterministic properties of median filters which are used to partition the local variances of the EMG traces into constant segments and edges between them. Th…

Internuclear ophthalmoplegia of abduction: clinical and electrophysiological data on the existence of an abduction paresis of prenuclear origin.

Three patients showed unilateral and five bilateral abduction paresis. Five had associated adduction nystagmus of the contralateral eye. Electrophysiological testing of masseter and blink reflexes indicated an ipsilateral rostral pontine or mesencephalic lesion, and excluded a lesion of the infranuclear portion of the abducens nerve. Abduction paresis was attributed to impaired inhibition of the tonic resting activity of the antagonistic medial rectus muscle. The prenuclear origin of the disorder is based on morphological and neurophysiological evidence of an ipsilateral inhibitory connection between the paramedian pontine reticular formation and the oculomotor nucleus running close to but …

The Inhibitory Effects of Prednisone, 16-Methylen-Prednisolone, and Acth on Con-A Induced Lymphokines (Interferon-Y) as Measured by the Chemiluminescence-Activity of Blood Monocytes

When lymphocytes are stimulated with mitogens or antigens they are enhanced via a cascade of lymphokines to produce interferon-y (IFN-y). IFN-y augments the H2O2 secretion of human monocytes which indirectly can be measured by chemiluminescence. We tested prednisone, 16-methylen-prednisolone and ACTH for their effect to inhibit the Con-A induced stimulation of the chemiluminescence-activity. All three hormones inhibited significantly the stimulation: prednisone up to 52.5% (concentration = 150 micrograms/ml, p = 0.000005), 16-methylen-prednisolone up to 22.5% (concentration = 2.5 micrograms/ml, p = 0.006) and ACTH up to 33% (concentration = 10 micrograms/ml, p = 0.0036).

Cerebrovascular Brainstem Diseases with Isolated Cranial Nerve Palsies

There is a significant number of individual patients with cranial nerve palsies as the sole manifestation of MRI- and, less frequently, CT-documented small brainstem infarctions or hemorrhages. The 3rd and 6th nerves are most commonly involved and, less frequently, the 4th, 5th, 7th, and 8th nerves. An intra-axial basis for such lesions may be underestimated if the diagnosis is based solely on MRI. The electrophysiologic abnormalities indicating brainstem lesions may be independent of MRI-documented morphological lesions. This paper reviews the literature on cerebrovascular brainstem diseases manifesting as isolated cranial nerve palsies. It supports the concept that small pontine and mesen…

Topodiagnostic value of blink reflex R1 changes: a digital postprocessing MRI correlation study.

The aim of the study was to investigate the relation of the blink reflex R1 arc to known anatomical brainstem structures. Acute vascular brainstem lesions as identified by magnetic resonance imaging (MRI) of patients with isolated R1 pathology were superimposed into a stereotactic anatomical atlas using a new method of digital postprocessing. Isolated acute brainstem lesions were documented by diffusion-weighted MRI in 12 of 24 patients with unilateral R1 pathology. The lesions were located in the ipsilateral mid- to lower pons. In three patients only, the lesion had partial contact with the principal sensory nucleus of the trigeminal nerve (PSN) on at least one level. In two patients, the …

Photoreactive flow changes in the posterior cerebral artery in control subjects and patients with occipital lobe infarction.

Background and Purpose Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA. Methods Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina. Results In 25 control subjects MFV was increased by 30.6±9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homon…

Sensitivity of laser-evoked potentials versus somatosensory evoked potentials in patients with multiple sclerosis

Somatosensory evoked potentials (SEPs) play a less important role in the diagnosis of multiple sclerosis (MS) than visually evoked potentials. Since standard SEPs only reflect the dorsal column function, we now investigated spinothalamic tract function in patients with MS using laser-evoked potentials (LEPs).LEPs to thulium laser stimuli (3ms, 540 mJ, 5mm diameter) were recorded from 3 midline positions (Fz, Cz, Pz) in 20 patients with MS, and 6 patients with possible but unconfirmed MS. Peak latencies and peak-to-peak amplitude of the vertex potential negativity (N2) and positivity (P2) were evaluated and compared with normative values from 22 healthy control subjects. Median and tibial ne…