Neurocognitive impairment associated with predominantly early stage HIV infection in Abuja,Nigeria

Detailed neuropsychological testing was performed on 133 human immunodeficiency virus (HIV) seropositive (SP) and 77 HIV seronegative (SN) individuals, 86 % with early stage HIV infection in Nigeria, to determine the frequency of HIV-related neurocognitive impairment among the HIV-infected group. The tests were administered to assess the following seven ability domains: speed of information processing, attention/working memory, executive functioning, learning, memory, verbal fluency, and motor function motor. Demographically corrected individual test scores and scores for each domain or reflecting a global deficit (a global deficit score, or GDS) were compared for the SP and SN groups. SP participants were older, had fewer years of education, were more likely to be married, differed in ethnicity, and had higher depression scores than SN individuals. Within the seven ability domains, SP performed worse than SN with respect to speed of information processing, executive function, learning, memory, and verbal fluency and also on the global measure. SP were also more frequently impaired on tests of SIP, and there was a borderline increase in the frequency of global impairment. On the individual tests, SP performed worse than SN on four tests that assessed learning, verbal fluency, memory, and motor function (the Timed Gait). SP subjects, however, performed better than SN on the Finger-tapping test, also a motor task. Performance by SP subjects was not associated on the timed gait which showed a borderline statistically significant correlation with CD4 counts. However, there were significant correlations between viral load measurements and individual tests of speed of information processing, executive function, learning, and verbal fluency and with overall executive function and a borderline correlation with the GDS. Depression scores for SP were associated with impairment on only a single test of executive function. These results demonstrate the ability of these assessments to identify areas of impairment that may be specifically linked to a history of HIV infection among individuals in Nigeria. Confirmation of these findings awaits analyses using data from a larger number of control subjects.     

Assessment of rat sciatic nerve function following acute implantation of high density utah slanted electrode array (25 electrodes/mm2) based on neural recordings and evoked muscle activity

Introduction: High density Utah slanted electrode arrays (HD‐USEAs) have been developed recently for intrafascicular access to submillimeter neural structures. Insertion of such high electrode density devices may cause nerve crush injury, counteracting the intended improved selective nerve fiber access. Methods: HD‐USEAs were implanted into sciatic nerves of anesthetized rats. Nerve function was assessed before and after HD‐USEA implantation by measuring changes in evoked muscle and nerve compound action potentials and single unit neuronal recordings. Results: Neural activity was recorded with over half of all implanted electrodes. Average decreases of 38%, 36%, and 13% in nerve, medial gastrocnemius, and tibialis anterior compound action potential amplitudes, respectively, were observed following array implantation. Only 1 of 8 implantations resulted in loss of all signals. Conclusions: These studies demonstrate that HD‐USEAs provide a useful neural interface without causing a nerve crush injury that would otherwise negate their use in acute preparations (<12 h). Muscle Nerve 50 : 417–424, 2014     

Disease spread through contiguity and axonal tracts in primary lateral sclerosis

Our goal in this report was to determine whether symptom progression in primary lateral sclerosis (PLS) was consistent with disease spread through axonal pathways or contiguous cortical regions. The date of symptom onset in each limb and cranial region was obtained from 45 PLS patient charts. Each appearance of symptoms in a new body region was classified as axonal, contiguous, possibly contiguous, or unrelated, according to whether the somatotopic representations were adjacent in the cortex. Of 152 spread events, the first spread event was equally divided between axonal (22) and contiguous (23), but the majority of subsequent spread events were classified as contiguous. Symptom progression in PLS patients is consistent with disease spread along axonal tracts and by local cortical spread. Both were equally likely for the first spread event, but local cortical spread was predominant thereafter, suggesting that late degeneration does not advance through long axonal tracts. Muscle Nerve 49 :439–441, 2014     

Blood‐based diagnostic testing for Pompe disease: Consistency between GAA enzyme activity in dried blood spots and GAA gene sequencing results

Introduction: We have identified a large consanguineous Lebanese family with 5 individuals with severe childhood‐onset recessive sensory loss associated with deafness and variable optic atrophy. Methods: Autozygosity mapping was performed in all affected individuals, followed by whole‐exome sequencing (WES) in 2 individuals. Results: WES identified a homozygous missense mutation (c.916G>A, p.G306R) in the cerebral riboflavin transporter SLC52A2, recently shown to cause Brown‐Vialetto‐Van‐Laere syndrome (BVVLS), which is considered primarily a motor neuronopathy. Our patients have a phenotype distinct from BVVLS, characterized by severe progressive sensory loss mainly affecting vibration and proprioception that evolves to include sensorineural hearing loss in childhood, variable degrees of optic atrophy, and marked upper extremity weakness and atrophy. Treatment of 3 patients with 400 mg/day riboflavin over 3 months produced definite clinical improvement. Conclusions: Mutations in SLC52A2 result in a recognizable phenotype distinct from BVVLS. Early recognition of this disorder is critical, given its potential treatability. Muscle Nerve 50 : 775–779, 2014     

Interleukin‐10 producing‐B cells and their association with responsiveness to rituximab in myasthenia gravis

Introduction: A subset of regulatory B cells in humans and mice has been defined functionally by their ability to produce interleukin (IL)‐10. We characterized IL‐10‐producing B (B10) cells in myasthenia gravis (MG) patients and correlated them with disease activity and responsiveness to rituximab therapy. Methods: Frequencies of B10 cells from MG patients and healthy controls were monitored by fluorescence‐activated cell sorting (FACS). Results: MG patients had fewer B10 cells than controls, which was associated with more severe disease status. Moreover, patients who responded well to rituximab therapy exhibited rapid repopulation of B10 cells, whereas in patients who did not respond well to rituximab, B10 cell repopulation was delayed. The kinetics of B10 cells were related to the responsiveness to rituximab in MG. Conclusions: We have characterized a specific subset of B10 cells in MG patients which may serve as a marker for disease activity and responsiveness to immune therapy. Muscle Nerve 49:487–494, 2014     

F‐wave latencies in patients with diabetes mellitus

Introduction: To evaluate the sensitivity of electrophysiologic assessments, we compared F‐waves and motor and sensory nerve conduction studies (MNCS and SNCS) in patients with diabetes mellitus (DM). Methods: We tested median, ulnar, tibial, and fibular nerves in 132 DM patients divided into those with and without clinical evidence of polyneuropathy. Results: Of 64 asymptomatic patients, 2 (3%) had MNCS or SNCS abnormalities, both of whom had F‐wave changes, whereas 21 (33%) had only delayed F‐waves, for a combined yield of 23 (36%). The corresponding values for 68 symptomatic patients consisted of 43 (63%), 14 (21%), and 57 (84%). In both groups, F‐wave latency had a higher (P < 0.05) frequency of abnormality than MNCS in all nerves. F‐wave study also surpassed SNCS in lower limb nerves. Conclusions: F‐waves of the tibial and fibular nerves are the most sensitive measure to detect subclinical or overt diabetic polyneuropathy. Muscle Nerve 49 : 804–808, 2014     

Changes in sensory function and force production in adults with type II diabetes

Introduction: The purpose of this study was to evaluate the relationship among sensory function, disease severity, and upper extremity force production in adults with type II diabetes (T2D) as compared with healthy age‐ and gender‐matched controls. Methods: Ten adults with T2D and 10 healthy age‐ and gender‐matched control subjects underwent a battery of sensory and motor function evaluations. Data on disease severity and duration were also collected. Results: The T2D group exhibited sensory deficits and altered force production as compared with healthy controls. Sensory function correlated with disease severity, as did signal predictability of kinetic output during submaximal force production tasks. Maximal force production tasks were associated with altered output in T2D, but these data did not correlate with disease severity or sensory dysfunction. Conclusions: Some, not all, motor performance deficits in T2D are associated with sensory dysfunction. Mechanisms responsible for these changes in adult‐onset T2D are described. Muscle Nerve 50: 984–990, 2014