Cerebellopontine epidermoid presenting with trigeminal neuralgia for 10 years: a case report

Trigeminal neuralgia, also called tic douloureux, is a common and potentially disabling pain syndrome, which affects the trigeminal or fifth cranial nerve. The precise pathophysiology of Trigeminal neuralgia remains obscure. The disorder causes extreme, sporadic, sudden burning or shock-like face pain that lasts from few seconds to minutes and can be physically and mentally incapacitating. More than one nerve branch can be affected by the disorder. A 55-year-old female presented with pain over the left side of face for 10 years uncontrolled with carbamazepine. On examination the positive findings were reduced sensation by 25% over the left side of face with House and Brackman grade II facial nerve palsy. The corneal reflex was absent on left side. Magnetic resonance imaging showed left cerebellopontine angle (CPA) mass suggestive of an epidermoid involving the Vth nerve and Gasserian ganglion and extending into the middle cranial fossa. She underwent left suboccipital craniectomy and near total excision of the tumor with decompression of the Vth nerve which was fully engulfed by the tumor. Postoperative the VII nerve palsy increased to grade III and she had 50% loss of sensation over left side. She had no further attacks of pain and hence tapered off the carbamazepine. TN caused by cerebellopontine angle epidermoids is uncommon and should be kept in view in all cases presenting with TN. The aim of surgery for epidermoids is to decompress the cranial nerves and brain stem and not total removal with its attendant morbidity and mortality

Induced pseudoscalar coupling of the proton weak interaction

The induced pseudoscalar coupling $g_p$ is the least well known of the weak coupling constants of the proton's charged--current interaction. Its size is dictated by chiral symmetry arguments, and its measurement represents an important test of quantum chromodynamics at low energies. During the past decade a large body of new data relevant to the coupling $g_p$ has been accumulated. This data includes measurements of radiative and non radiative muon capture on targets ranging from hydrogen and few--nucleon systems to complex nuclei. Herein the authors review the theoretical underpinnings of $g_p$, the experimental studies of $g_p$, and the procedures and uncertainties in extracting the coupling from data. Current puzzles are highlighted and future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic

On determinations of the pion3He3H coupling constant

Various determinations in the current literature of the π3He3H coupling constant are reexamined, and the ones leading to very low values are shown either to be erroneous or not decisive and implausible. A dispersion relation and the impulse approximation which use the same kind of approximations both lead to Gπ−3He−3H(−m2π) ≈ −1.7, in absolute value higher than the elementary nucleon value gπpn(−m2π)=1.41