Jan Hannerz

The fatigue and voluntary discharge properties of single motor units in man.

1. The discharge properties of single motor units during prolonged maximal voluntary effort have been studied using electromyographic recordings, mainly in the short big toe extensor muscle but also in the anterior tibial muscle.

MR imaging of cerebrospinal fluid dynamics in health and disease. On the vascular pathogenesis of communicating hydrocephalus and benign intracranial hypertension.

The CSF flows in the aqueduct and at the foramen magnum were examined in 5 patients with communicating hydrocephalus (HC) and in 10 with benign intracranial hypertension (BIH) as well as in 5 healthy volunteers. As compared to normal individuals, the aqueductal flow in HC was about 10 times larger and the cervical flow was half as large. In BIH the CSF flows were not different from those of normal volunteers. The decreased arterial expansion as reflected in the reduced cervical flow in HC may be due to pathologic changes in the arteries and paravascular spaces. The large aqueductal flow in HC reflects a large brain expansion, causing increased transcerebral mantle pressure gradient and ventricular dilatation. In BIH there is a normal brain expansion (aqueductal flow) and consequently no ventricular dilatation. It is argued that BIH be caused by an obstruction on the venous side, as opposed to the vascular alterations in HC, which are on the arterial side.

Contraction time and voluntary discharge properties of individual short toe extensor motor units in man.

1. The contraction time and the voluntary discharge properties of forty‐five short toe extensor motor units were studied in man. 2. The contraction time of the individual motor unit was studied by using selective electrical nerve stimulation or by averaging the increase in force related to its electromyographic potential in tonic voluntary contraction. 3. Both methods showed a range of contraction times from 40 to 90 ms. 4. The discharge properties of the individual motor unit were studied with e.m.g. techniques, permitting the identification of its potentials during maximum voluntary effort. 5. A motor unit which could be driven continously and had a minimum rate of about 10/s and a maximum rate of about 30/s had a contraction time between 60 and 90 ms. 6. A motor unit which could not be driven continously and had a minimum rate of about 20/s and a maximum rate above 40/s had a contraction time between 40 and 55 ms. 7. A motor unit with intermediate voluntary discharge properties had an intermediate contraction time. 8. It is concluded that each motor unit fires at its fusion frequency in voluntary contraction and that the voluntary discharge frequency range of a motor unit can be used as an indication of its contraction time.

Orbital phlebography in patients with cluster headache

Thirteen patients with cluster headache in an active stage were investigated with orbital phlebography. About 60% of the patients showed pathologic changes on the phlebograms, such as changes in the appearance of the superior ophthalmic vein. Five patients had pathologic changes on both sides and three patients on one side only. All patients with unilateral pathologic findings on orbital phlebography had the attacks on the same side. The phlebographic findings in these patients with cluster headache were very similar to those of patients with the Tolosa-Hunt syndrome. There is also some similarity in the symptoms in the two disorders. It has previously been suggested that the Tolosa-Hunt syndrome is caused by venous vasculitis, and the present findings to some extent support the idea that cluster headache may have the same etiology.

Axonal conduction velocity and voluntary discharge properties of individual short toe extensor motor units in man.

1. The axonal conduction velocity and the voluntary discharge properties of 120 short toe extensor motor units were studied in man. 2. Electromyographic techniques were used which permitted the identification of individual motor unit potentials after proximal and distal electrical nerve stimulation and during maximum voluntary effort. 3. The necessary selectivity of the e.m.g. recordings was achieved in two circumstances. In some subjects, previous motor nerve lesions distal to the point of stimulation had led to collateral sprouting with larger motor unit potentials. In other subjects an accessory deep peroneal nerve was present, so that lidocaine block of the main motor nerve left a small number of innervated motor units. 4. The axonal conduction velocities of the individual motor units ranged from 30 to 54 m/sec with most motor units between 35 and 45 m/sec. 5. Motor units which voluntarily could be driven continuously at frequencies below 10/sec had axonal conduction velocities between 30 and 45 m/sec. 6. Motor units which on voluntary drive responded only in high frequency bursts had axonal conduction velocities between 40 and 54 m/sec. 7. Motor units with intermediate voluntary discharge properties had intermediate axonal conduction velocities. 8. Thus a relationship was established between voluntary discharge properties and axonal conduction velocity.

A case of parasellar meningioma mimicking cluster headache.

A medical history of a 46-year-old male is reported. At 23 years of age, he started having diffuse pain in the left side of his head for up to 30 min once or twice a month. At 28, the pain changed into left-sided cluster headache-like attacks with 2–3 h duration and with ipsilateral conjunctival injection, lacrimation, and rhinnorhea, but with short-lasting free intervals of about two to three weeks. At 36, the pattern of the attacks corresponded to chronic migrainous neuralgia. At 40, the symptoms changed to painful ophthalmoplegia-picture. A left-sided parasellar meningioma was then diagnosed. Removal of the tumor caused complete amelioration. The case history is suggested to support the hypothesis that the cavernous sinus region is involved in cluster headache.

MR imaging of cerebrospinal fluid dynamics in health and disease

The CSF flows in the aqueduct and at the foramen magnum were examined in 5 patients with communicating hydrocephalus (HC) and in 10 with benign intracranial hypertension (BIH) as well as in 5 healt...

The Relationship Between Idiopathic Intracranial Hypertension and Obesity

Objective.— Idiopathic intracranial hypertension (IIH) is usually considered to result from deficient intracranial absorption of cerebrospinal fluid, but has also been suggested to be caused by decreased cranial venous flow because of increased intrathoracic pressure resulting from intra‐abdominal obesity. To test this hypothesis, cerebrospinal fluid pressure (Pcsf), extracranial venous pressure (Pvf), intracranial venous pressure, and body mass index (BMI) were studied in patients with IIH with papilledema compared with patients with chronic tension‐type headache (CTTH).

Trigeminal Neuralgia with Chronic Paroxysmal Hemicrania: The CPH-Tic Syndrome

A case of chronic paroxysmal hemicrania-tic syndrome is described. The chronic paroxysmal hemicrania (CPH) was controlled with indomethacin and the trigeminal neuralgia with a glycerol blockade. The trigeminal neuralgia reappeared four years after the blockade and was then treated successfully with corticosteroids. Six months later, when indomethacin was stopped, the trigeminal neuralgia recurred and resolved again with corticosteroids. We suggest that the CPH-tic syndrome is due to periorbital venous vasculitis. To our knowledge this is the first reported case of this disorder.

Recurrent Tolosa-Hunt syndrome

Twenty consecutive patients with recurrent Tolosa-Hunt syndrome were studied. One had a parent who suffered from recurrent Tolosa-Hunt syndrome. Thirty-three percent of the patients had also recurrent periods of weeks to months of unilateral periorbital pain without ophthalmoplegia. One patient had cluster headache before the Tolosa-Hunt syndrome started. Some patients had involvement of cranial nerves outside the cavernous sinus region during Tolosa-Hunt syndrome and also between episodes. The same systemic symptoms, i.e. back pain, cold feet, arthralgia, gut problems, varices, vertigo, chronic fatigue, thrombophlebitis, memory deficiency and signs of inflammation in serum, occurred in Tolosa-Hunt syndrome as earlier found in patients with orbital venous vasculitis. Seventy-three percent of the patients had pathologic orbital phlebograms. All patients treated with steroids reacted promptly; four who developed chronic pain syndromes were treated satisfactorily with azathioprine.