Medial temporal lobe functional connectivity predicts stimulation-induced theta power.

Focal electrical stimulation of the brain incites a cascade of neural activity that propagates from the stimulated region to both nearby and remote areas, offering the potential to control the activity of brain networks. Understanding how exogenous electrical signals perturb such networks in humans is key to its clinical translation. To investigate this, we applied electrical stimulation to subregions of the medial temporal lobe in 26 neurosurgical patients fitted with indwelling electrodes. Networks of low-frequency (5-13 Hz) spectral coherence predicted stimulation-evoked increases in theta (5-8 Hz) power, particularly when stimulation was applied in or adjacent to white matter. Stimulation tended to decrease power in the high-frequency broadband (HFB; 50-200 Hz) range, and these modulations were correlated with HFB-based networks in a subset of subjects. Our results demonstrate that functional connectivity is predictive of causal changes in the brain, capturing evoked activity across brain regions and frequency bands.

Widespread theta synchrony and high-frequency desynchronization underlies enhanced cognition.

The idea that synchronous neural activity underlies cognition has driven an extensive body of research in human and animal neuroscience. Yet, insufficient data on intracranial electrical connectivity has precluded a direct test of this hypothesis in a whole-brain setting. Through the lens of memory encoding and retrieval processes, we construct whole-brain connectivity maps of fast gamma (30-100 Hz) and slow theta (3-8 Hz) spectral neural activity, based on data from 294 neurosurgical patients fitted with indwelling electrodes. Here we report that gamma networks desynchronize and theta networks synchronize during encoding and retrieval. Furthermore, for nearly all brain regions we studied, gamma power rises as that region desynchronizes with gamma activity elsewhere in the brain, establishing gamma as a largely asynchronous phenomenon. The abundant phenomenon of theta synchrony is positively correlated with a brain region's gamma power, suggesting a predominant low-frequency mechanism for inter-regional communication.

[Non-traumatic corneal perforations: Therapeutic modalities]. / Perforations cornéennes non traumatiques : modalités thérapeutiques.

INTRODUCTION: The treatment of non-traumatic perforations of the cornea is a real challenge for the choice of surgical technique as well as for management of the causal pathology. The goal of our study is to determine the anatomical and functional results of the management of non-traumatic perforation of the cornea in the absence of ready access to a corneal graft. MATERIALS AND METHODS: This is a retrospective, non-comparative monocentric study of 23 consecutive cases diagnosed and treated between January 2011 and January 2013. We included 23 eyes with non-traumatic corneal perforation. Various surgical techniques were used depending on the size and location of the corneal perforation. RESULTS: The predominant etiology of the corneal perforations in our series was corneal abscess, found in 30.4% of cases (7 eyes). A conjunctival flap was performed in 43.5% of cases (10 eyes) followed by tarsorrhaphy in 21.7% of cases (5 eyes), autologous corneal patch in 17.4% of cases (4 eyes), amniotic membrane in 13% of cases (3 eyes) and finally cyanoacrylate glue in one case. Mean follow-up was 12.4 ± 2.1 months. Anatomical closure of the corneal perforation was achieved in 91.3% of cases (21 eyes), while the final visual acuity was not improved due to secondary opacities. DISCUSSION: The choice of surgical technique depends on the size of the corneal perforation, its location, its etiology and the resources available for emergencies. When amniotic membrane and corneal donor tissue are unavailable, conjunctival flap is an easy and effective technique, which is a good alternative to close corneal perforations less than 3mm. It improves ocular surface quality and prepares the eye for later penetrating keratoplasty. CONCLUSION: Conjunctival flap is a good technique that is still relevant today, especially in the absence of corneal donor tissue or amniotic membrane. The anatomical success rate is very satisfactory, but sometimes several interventions are needed to improve the visual prognosis.

[Retinoblastoma: preliminary results of national treatment protocol at Casablanca university medical center]. / Rétinoblastome : résultats préliminaires du protocole national de prise en charge au CHU de Casablanca.

Retinoblastoma is the most frequent intraocular cancer, affecting almost exclusively children. We report prospective study results assessing the national protocol for retinoblastoma treatment in Morocco. Treatment included, depending on stage and laterality, primary chemotherapy either to facilitate enucleation or to make conservative treatment possible, postoperative chemotherapy, enucleation and conservative treatments such as transpupillary thermotherapy, thermochemotherapy and cryotherapy. Radiation was used in a few cases. Close supervision was performed until the age of 5. The incidence of retinoblastoma within the study period was 18 new cases per year in our department. Observations of 32 children were included in the study: 18 unilateral retinoblastomas (56%) and 14 bilateral retinoblastomas (44%), for a total of 46 eyes. Leucocoria was the most frequent presenting symptom (69%). Buphthalmia or proptosis were present in 47% of cases. The stage of retinoblastoma was V/D or E (Reese-Elsworth/ABC) in 69.5% of cases. Enucleation was necessary for 28 eyes. Transpupillary thermotherapy or thermochemotherapy were used for 13 eyes (11 children) and cryotherapy for 13 eyes (10 children). After an average follow-up period of 52 months, among 32 children, 4 died and 2 abandoned treatment. Ocular salvage rate was 85.7% (12 eyes out of 14, among which 11 without radiation). Retinoblastoma is a genetic tumor, which occurs in two forms: sporadic, always unilateral, and hereditary, often bilateral. The latter is the most challenging case. Current treatment protocols rely primarily on chemotherapy and local treatments. The future is oriented toward purely local treatments such as intra-arterial chemotherapy and intraocular chemotherapy.

[Pseudophakic retinal detachment: how to manage?]. / Décollement de rétine du pseudophaque : quelle prise en charge ?

INTRODUCTION: Retinal detachment, a common complication of cataract surgery, requires urgent surgical treatment. The external approach combining retinopexy with scleral buckling remains the gold standard in the surgical management of pseudophakic retinal detachment (RD) without marked proliferative vitreoretinopathy (PVR), although intraocular surgery is currently preferred by most of the authors. The purpose of this study is to compare the anatomical and functional results obtained with both techniques. PATIENTS AND METHODS: This study compares the results of two techniques for treating pseudophakic retinal detachment: external surgery (group I), and vitrectomy with internal tamponade (group II). Ab-externo surgery was performed in 24 patients (24 eyes), while 22 patients (22 eyes) underwent primary vitrectomy. In order to make both groups comparable, we excluded recurrences of RD, vitreous hemorrhage and other media opacities, giant tears and initial grade C PVR. Minimum follow-up was 12 months. Postoperative variables analyzed and compared were the rate of initial and final anatomical success, final visual acuity, and causes of failure of the initial surgery. RESULTS: The retina was reattached with a single operation in 21 eyes in group I (87.5%) and 19 eyes in group II (86.4%) (P=0.91). The causes of anatomical failure in both groups were proliferative vitreoretinopathy (4 cases) and secondary tears or tears not seen on initial examination (2 cases). For patients in group I, secondary surgery consisted of total vitrectomy with encircling buckle. Patients in group II underwent an additional vitrectomy (peeling of vitreoretinal proliferation, and silicone oil tamponade as necessary). After a mean follow-up of 12 months, the final examination noted a reattached retina in 23 eyes in group I (95.84%) and 21 eyes in group II (95.45%) (P=0.95). The final visual results were identical at comparable follow-up periods. Indeed, the final visual acuity was similar in the two groups with nearly 40% of patients having recovered visual acuity between 1/10 and 5/10 (P=0.98). CONCLUSION: With regard to surgical treatment of pseudophakic retinal detachment, vitrectomy with internal tamponade provides anatomical and functional results comparable to those obtained with external surgery.

Temporal macrodynamics and microdynamics of the postoperative impedance at the tissue-electrode interface in deep brain stimulation patients.

OBJECTIVE: To study the temporal dynamics of tissue impedance after deep brain stimulation (DBS). BACKGROUND: DBS therapy commonly employs a constant voltage approach, and current delivery to the tissue is a function of electrode-tissue impedance. It is presumed that impedance fluctuates early postimplantation, with implications for variations in current delivery and therapeutic efficacy. We hypothesised that the largest variation will be recorded early after surgery, followed by stabilisation. METHODS: Review of impedance checks of implanted DBS systems at standard parameters during the first five months postimplantation. All measurement time points were binned into 1-week periods, and we used repeated measures analysis of variance with Tukey pairwise multiple comparisons correction. The analysis was repeated after normalising impedance values for each subject to that patient's baseline value. RESULTS: There was an initial (non-significant) drop in impedance at week 1, followed by significant increase at week 3 (p=0.0002). There were no further significant differences in impedance values at subsequent time points. Analysis of normalised data showed a significant difference between the initial measurement in postoperative week 1 (normalised value 1) and week 3 (normalised value 1.73, p<0.0001), with no further difference among the subsequent weekly points during the 5-month follow-up. No significant hourly variations were found at any time points. CONCLUSIONS: We found major changes in impedance within the first month postimplantation, with no further variation. This is an important confirmation in patients of this temporal dynamics of the impedance of implanted DBS hardware, with potential therapeutic implications.

[Möbius syndrome]. / Le syndrome de Möbius.

Möbius syndrome is a rare congenital disease characterized by facial and abducens nerve palsy. Children are unable to smile, frown, suck, grimace, blink their eyes, and to move their eyes laterally. The aim of this study was to analyze the diagnosis and treatment of this disease. Maxillofacial examination reveals: facial diplegia, retrognathism, palatine and dental malformations. Möbius syndrome is usually associated with multiple cranial nerve involvement, limb or orofacial malformation, and Poland syndrome. Although the pathogenesis of the syndrome is unclear, a number of mechanisms have been suggested including vascular and genetic hypotheses. Symptomatic treatment is used to manage this syndrome. The diagnosis of Möbius syndrome may be difficult in some patients with atypical signs of facial diplegia and other cranial nerve palsies, it requires a multidisciplinary approach.

[Efficacy assessment of azithromycin 1.5% eye drops versus tobramycin 0.3% on clinical signs of purulent bacterial conjunctivitis]. / Evaluation de l'efficacité d'un collyre azithromycine 1,5% versus tobramycine 0,3% sur les signes cliniques de la conjonctivite bactérienne purulente.

INTRODUCTION: Bacterial conjunctivitis is characterized by hyperemia and discharge of one or both eyes. These clinical signs appear quickly and are contagious. This study compares the clinical efficacy (signs and symptoms) and safety of azithromycin 1.5% eye drops with tobramycin 0.3%. PATIENTS AND METHODS: This was a multicenter, randomized, investigator-masked study including 1,043 patients with purulent bacterial conjunctivitis. Patients received either azithromycin twice daily for 3 days or tobramycin, 1 drop every 2 hours for 2 days, then four times daily for 5 days. The primary variable was clinical cure at the test-of-cure (TOC) visit (D9) on the worst eye. The cure was defined as bulbar conjunctival injection and discharge scores of 0. Clinical signs were evaluated at D0, D3, and D9. RESULTS: In the azithromycin group 87.8% of patients and in the tobramycin group 89.4% were clinically cured at D9. Clinical cure with azithromycin was not inferior to tobramycin at D9: discharge was absent in 96.3% of patients treated with azithromycin and 95.1% with tobramycin. Azithromycin was well tolerated. CONCLUSIONS: Azithromycin 1.5% for 3 days (six drops) was as effective as tobramycin for 7 days (36 drops). Furthermore, patients on azithromycin presented earlier clinical cure on Day 3 than patients on tobramycin. Azyter, with its convenient dosing (bid for 3 days), is a step forward in the management of purulent bacterial conjunctivitis.

[Manifestation of congenital rubella syndrome: clinical and epidemiologic aspects]. / Les manifestations ophtalmologiques de la rubéole congénitale: aspects cliniques et épidémiologiques.

INTRODUCTION: Congenital rubella syndrome is an ensemble of congenital malformations which results from a primary viral infection in non-immunised pregnant women. The main ophthalmologic manifestation is cataract. It involves at the same time visual and vital prognosis and can be responsible for multiple handicaps. METHODS: We did a retrospective study of 16 infants (32 eyes) having undergone congenital cataract surgery compatible with congenital rubella syndrome in the Casablanca paediatric ophthalmology department between January 2001 and December 2005. All the patients underwent a complete ophthalmologic examination, otorhinolaryngologic, cardiovascular and neurological examinations, and paraclinic explorations. RESULTS: The results were compared with those reported in the literature. In our series, 25 eyes (78.12%) had a cataract of which 56% were nuclear, 13 eyes (40.62%) had microphthalmia. One case each of corneal dystrophy and iris coloboma were described. Congenital glaucoma was found in only one case. Pigmentary retinopathy was found in 12 eyes (37.5%). Seven patients (43.75%) had associated cardiac anomalies, 6 (37.5%) deafness, 5 (31.25%) psychomotor delay and 2 (12.5%) facial dysmorphy. CONCLUSION: Considering the permanent disabilities caused by congenital rubella syndrome, care should be taken with the follow-up of the pregnancies and an immunization program should be implemented for good control of the circulation of the virus.

[Necrotizing fasciitis caused by pseudomonas aeruginosa (an obervation)]. / Fasciite nécrosante à pseudomonas aeruginosa (à propos d' une observation).

Necrotizing fasciitis is an exceptional and severe form of subcutaneous gangrene which requires early diagnosis and emergency treatment. We report the case of a 24 year old woman presenting with necrotizing fasciitis after pansinusitis resistant to treatment. The germ detected was pseudomonas aeruginosa. The infection was controled with intensive care, antibiotics and surgical resection of necrotic tissues. The aim of this observation is to highlight the clinical characteristics of this disease, and to insist on the necessity to recognize the early symptoms and to start treatment as soon as possible.

[Postoperative pain in retinal detachment surgery]. / Douleur postopératoire dans la chirurgie de décollement de rétine.

Postoperative pain in retinal detachment surgery is frequent but it is often underestimated. The aim of this study was to determine the incidence of postoperative pain after retinal detachment surgery and to identify its predictive factors in a longitudinal study. We included 106 patients operated for retinal detachment surgery using an endo-ocular or exo-ocular approach with general anesthesia. Postoperative monitoring for 24 h evaluated the intensity of pain using a numerical scale. The possible predictive factors of this pain were studied: ocular antecedents, premedication, total amount of morphine used, type of surgery, duration of surgery, and vomiting. The incidence of postoperative pain was 57.5%, 56% of which was intense pain. Postoperative pain was greatest during the first 4 h. The predictive factors of this pain revealed by bivariate analysis of the data were the type of surgery and vomiting. The incidence and intensity of postoperative pain after retinal detachment surgery remain high. Pain management requires postoperative treatment of vomiting as well as the development of the endo-ocular surgery and locoregional anesthesia techniques.

[Bilateral optic neuropathy and non-Hodkin's lymphoma]. / Neuropathie optique bilatérale et lymphome non Hodgkinien.

UNLABELLED: While ocular lesion is commonly known in lymphoma, optic neuropathy is very rare : 1,3% of lymphomas affecting the central nervous systems. OBSERVATION: Authors report the case of a 75 year old patient treated in the haematology department for 8 years, for a large cell B phenotype stage IV lymphoma for which he received 7 chemotherapy courses (CHOP protocol). After a 4 year remission period, he presented a relapse with a rapid progressive bilateral impairment of visual acuity observed for a week before his admission. The ophthalmologic exam revealed no light perception and no afferent reflex on the right eye. There was light perception and weak afferent reflex on the left eye. The anterior segment was normal on both eyes and fundus examination revealed a bilateral stage I papillar oedema. The general exam showed a right facial palsy and an impairment of general condition. The orbital CT scan revealed a significant thickening of both optic nerves caused by lymphomatous infiltration. A chemotherapy with highly dosed IV and intrathecal methotrexate was performed. DISCUSSION: the optic neuropathy is usually associated with a generalized lymphoma with central nervous system involvement, but sometimes can precede the systemic spread of the disease. Apart from infiltration, the optic nerve can be compressed by an intracranial or orbital tumor. The optic neuropathy can also be caused by lymphomatous leptomeningitis.

[Primary palpebral tuberculosis (case report)]. / La tuberculose palpebrale primaire (a propos d'un cas).

Cutaneous tuberculosis is an uncommon disease and tuberculosis affecting the eyelid alone is even more rare. The clinical presentation is polymorphous which explains a diagnosis delay. Its treatment is based on antitubercular drugs chemotherapy. Authors report through an observation the case of a child with eyelid tuberculosis and discuss a difficult diagnosis, a physiopathogeny of eyelid tuberculosis, its diagnosis and treatment.

[Fraser syndrome. A case report]. / Syndrome de Fraser.

Fraser syndrome is a rare autosomal recessive disorder; the most consistent features are cryptophthalmos, syndactyly of fingers and toes, laryngeal stenosis, and urogenital abnormalities. We report a newborn case at day 1 of life who had multiple abnormalities, born from a consanguineous marriage. Clinically, the newborn had an ankyloblepharon on the left side, a cryptophthalmos on the right side, a syndactyly, anorectal abnormalities with ambiguous genitalia, laryngeal stenosis, and ear malformations. TDM of the cranium and orbits and the transfontanel ultrasound were normal. The abdominal ultrasound showed renal abnormalities. Right eye surgery showed a reduced cornea to an opaque thin plate clinging to the iris without an anterior chamber and a nonindividualized eyeball. The authors discuss the morphological abnormalities, the clinical and paraclinical aspects of this syndrome, its multispecialized clinical management, and the importance of prenatal diagnosis.

[Not Available]. / Les Lesions Oculaires Par Jeu de Feu au Cours de Achoura.

Les enfants célèbrent la fête de Achoura au Maroc par des jeux de feu, ce qui occasionne des blessures oculaires plus au moins graves. Nous rapportons 15 observations de malades traités au Service d'Ophtalmologie Pédiatrique de l'Hôpital 20 Août 1953 de Casablanca. L'âge moyen des patients était de 12 ans et demi, avec des extrêmes de 3 et 25 ans. Les pétards, la première cause des accidents (50%), ont occasionné des contusions oculaires avec parfois un oedème de Berlin (deux cas). L'atteinte oculaire par fusée a occasionné un éclatement de globe et une plaie de paupière. Les bombes de carbone ont été responsables de brûlures de deuxième degré palpébrales et conjonctivo-cornéennes avec de multiples corps étrangers cornéens profonds. Les «étoiles¼ et la limaille de fer ont provoqué des brûlures cornéennes moins graves avec des corps étrangers superficiels. Les pistolets à bille ont été responsables de contusions oculaires. La réglementation de vente des jeux de feu et la sensibilisation du grand public par les moyens audiovisuels permettraient de prévenir ces blessures oculaires.