Behavioral and neuroimaging evidence for impaired executive function in “cognitively normal” older HIV-infected adults

The increased prevalence of HIV among adults >50 years underscores the importance of improving our understanding of mechanisms causing HIV-associated neurocognitive disorders (HAND). Identifying novel and noninvasive diagnostic predictors of HAND prior to clinical manifestation is critical to ultimately identifying means of preventing progression to symptomatic HAND. Here, using a task-switching paradigm, in which subjects were cued (unpredictably) to perform a face-gender or a word-semantic task on superimposed face and word images, we examined the behavioral and neural profile of impaired cognitive control in older HIV?+?adults (N?=?14, 9 HIV+). Functional magnetic resonance imaging (fMRI) and behavioral data were acquired while subjects were performing the face-gender or word-semantic task. We found that, despite comparable performance in standard neuropsychology tests that are designed to probe executive deficits, HIV-infected participants were significantly slower than uninfected controls in adapting to change in task demand, and the behavioral impairments can be quantitatively related to difference in fMRI signal at the dorsal anterior cingulate cortex (ACC). Due to the limited sample size of this hypothesis-generating study, we should take caution with these findings and future studies with a large and better matched sample size are needed. However, these rather novel findings in this study have a few important implications: first, the prevalence of cognitive impairments in HIV+ older adults might be even higher than previously proposed; second, ACC (in particularly its dorsal region) might be one of the key regions underlying cognitive impairments (in particularly executive functions) in HIV; and third, it might be beneficial to adopt paradigms developed and validated in cognitive neuroscience to study HAND, as these techniques might be more sensitive to some aspects of HIV-associated neurocognitive impairments than standard neuropsychology tests.     

Peripheral Neurectomy: Minimally Invasive Surgical Modality for Trigeminal Neuralgia in Indian Population: A Retrospective Analysis of 20 Cases

Objective

To evaluate the efficacy of peripheral neurectomy in 20 cases of trigeminal neuralgia as minimally invasive surgical treatment modality.

Materials and methods

Twenty (12 males and 8 females) patients with trigeminal neuralgia aged between 35 and 68 years (mean 48 years), who had undergone peripheral neurectomy, were retrospectively analyzed for relief of pain, complications, recurrence of pain, and any additional procedure required to treat recurrence, in a follow-up period of 36 months postoperatively.

Results

There was no significant intra-operative and post-operative complications. There was recurrence of pain in two patients (10 %) in 24 and 28 months post-operative follow-up respectively, whereas, rest of the 18 patients were symptom free during 36 months follow-up.

Conclusion

Peripheral neurectomy is one of the minimally invasive and expeditious forms of surgical modality for the treatment of trigeminal neuralgia. This treatment option is cost effective and provides long term relief from neuralgic pain.     

Indicators of Mobility,Socio-Economic Vulnerabilities and HIV Risk Behaviours Among Mobile Female Sex Workers in India

This paper examines the relationship between indicators of mobility, socio-economic vulnerabilities, and HIV risk behaviours among 5,498 mobile female sex workers (FSWs) living in the four high HIV prevalence states in India. Female sex workers with greater degree of mobility reported significantly more often than the FSWs with lesser degree of mobility that they experienced physical violence, and consumed alcohol prior to sex. Further, FSWs with greater degree of mobility reported significantly more often than the FSWs with lesser degree of mobility that they had inconsistent condom use in sex with clients, even after controlling for several demographic characteristics and socio-economic vulnerabilities including experiences of violence. Additionally, short duration visits and visit to the Jatra (religious fairs) places found to have significant association with their inconsistent condom use in sex with clients as well as continuation of sex despite having STI symptoms. These findings suggest the need for screening FSWs for higher degree of mobility and to mobilize them to form community networks so as to deal with violence, reduce alcohol use and promote consistent condom use along the routes of mobility. HIV prevention interventions aimed at FSWs require an increased attention to address the socio-economic vulnerabilities including alcohol use, with particular emphasis on those FSWs who are on the move in India and elsewhere.     

Cystic cerebellar schwannoma.

Cystic cerebellar schwannoma is a rare tumour which may not be considered when a low attenuation computed tomographic (CT) lesion is seen in the cerebellar parenchyma. Since the origin of the Schwann cell in the cerebellar parenchyma is conjectural, immunohistochemical techniques are necessary for a diagnosis.     

Validation of diagnostic criteria for solitary cerebral cysticercus granuloma in patients presenting with seizures

Objective - To evaluate a set of clinical and computed tomographic (CT) criteria (previously described by us) to predict the diagnosis of a solitary cerebral cysticercus granuloma (SCCG) at initial presentation, in patients presenting with seizures. Material and methods - The diagnostic criteria were applied prospectively to patients presenting with seizures and solitary lesion on the CT scan. The clinical diagnostic criteria were as follows: seizures should be the presenting complaint; there should be no evidence of persistent raised intracranial pressure, progressive neurological deficit or an active systemic disease. The CT diagnostic criteria were: evidence of a solitary contrast enhancing lesion measuring 20 mm or less in its maximal dimension without a shift of the midline structures due to the surrounding oedema. A diagnosis of SCCG was made only when all the clinical and CT criteria were fulfilled. Over a period of 36 months, we managed 401 patients presenting with seizures and a solitary mass on the CT scan; 215 met the criteria for the diagnosis of an SCCG. Results - Of the 215 patients initially diagnosed to have an SCCG, 197 were ultimately determined to have that diagnosis (true positive diagnosis) while 16 were excluded because of lack of follow-up CT assessment. Two of the 215 patients with the initial diagnosis of an SCCG subsequently had histological diagnosis of a secondary metastasis and a pyogenic abscess (false positive diagnosis). Our set of diagnostic criteria for SCCG had a sensitivity of 99.5%; specificity of 98.9%; a positive predictive value of 99%; and a negative predictive value of 99.5%. The likelihood ratios for the positive and negative tests were 92.99 and 0.005 respectively. Conclusions - Our diagnostic criteria help in not only accurately identifying an SCCG but also in differentiating it from a solitary tuberculoma and other brain masses. However, confirmation of the diagnosis of an SCCG is only obtained at follow-up evaluation and therefore careful clinical and CT re-evaluation is essential in all patients initially diagnosed to have an SCCG.     

Intraoperative ultrasound in determining the extent of resection of parenchymal brain tumours – a comparative study with computed tomography and histopathology

Summary ¶Background. Radical excision of parenchymal brain tumours is generally associated with a better long-term outcome; however, it is difficult to ascertain the extent of resection at surgery. We used intra-operative ultrasound [IOUS] to help detect residual tumour and define the tumour-brain interface. Methods. Thirty-five patients with parenchymal brain lesions including 11 low-grade and 22 high-grade tumours and 2 inflammatory granulomata were included in the study. The IOUS was used to localize tumours not seen on the surface, define their margins and assess the extent of resection at the end of surgery. Multiple samples from the tumour-brain interface which were reported as tumour or normal tissue on IOUS were submitted to histopathology. The IOUS findings were compared with a postoperative contrast enhanced computed tomogram [CT] and with histopathology. Results. All tumours irrespective of histology were hyperechoic on IOUS. IOUS was useful in localizing those tumours not seen on the surface of the brain. In 71.4% of cases IOUS was useful in defining their margins, however in the remaining cases the margins were ill-defined. The tumour margins were ill-defined in those treated previously by radiation. With regard to the extent of excision, after excluding the cases who were irradiated, it was found that in the 28 patients who had parenchymal neoplasms, there was concordance between the ultrasound findings and the postoperative CT scan in 23 cases. Of the 79 samples taken from the tumor-brain interface which were reported as tumour on ultrasound, 66 had histopathological evidence of tumour while 13 samples were negative for tumour. On the other hand, in the tissue sent from 17 sites where the IOUS showed no residual tumour, 2 were positive for tumour on histopathology while 15 were negative. Interpretation. In conclusion, IOUS is a cheap and useful real-time tool for localizing tumours not seen on the brain surface, for defining their margins and for determining the extent of resection.Published online May 19, 2003     

Clinicoradiological and pathological correlations in patients with solitary cysticercus granuloma and epilepsy: focus on presence of the parasite and oedema formation.

A study of the clinical, radiological, and pathological correlations in 43 patients with solitary cysticercus granuloma and epilepsy focused on factors that might help in predicting the presence of the parasite in the granuloma and those that might influence the formation of oedema around the granuloma. The duration of symptoms (< six months and > or = six months) and CT morphology of the granuloma (ring and disc, type A; nodular lesion, type B) were studied as factors that could possibly predict the presence of the parasite in the granuloma. The influence of sex of the patient and the presence of a neutrophilic response in the granuloma on the intensity of oedema around the lesion as seen on CT was also studied. The pathological features were studied in the excised granulomas. The intact or degenerated form of the cysticercus was evident in 22 of 43 specimens. Neither the duration of seizures (P = 0.17) nor the type of lesion on CT (P = 0.16) was predictive of the presence of the parasite in the granuloma. The sex of the patient (P = 0.51) and the neutrophilic response in the specimen (P = 0.73) did not correlate with the degree of oedema on CT indicating that neither of these host factors was a major determinant of oedema production. The findings point to the varied and unpredictable natural history of solitary cysticercus granulomas and the complex nature of host-parasite interactions in individual patients. The inability to predict the presence of the parasite in the granuloma on the basis of the clinical or radiological features precludes a selection of patients with such lesions for cysticidal drug treatment.