Aberrant occipital dynamics differentiate HIV-infected patients with and without cognitive impairment. Wiesman, A. I., O'Neill, J., Mills, M. S., Robertson, K. R., Fox, H. S., Swindells, S., & Wilson, T. W. Brain : a journal of neurology, 141(6):1678–1690, June, 2018. Place: England
doi  abstract   bibtex   
Combination antiretroviral therapies have revolutionized the treatment of HIV infection, and many patients now enjoy a lifespan equal to that of the general population. However, HIV-associated neurocognitive disorders (HAND) remain a major health concern, with between 30% and 70% of all HIV-infected patients developing cognitive impairments during their life time. One important feature of HAND is visuo-perceptual deficits, but the systems-level neural dynamics underlying these impairments are poorly understood. In the current study, we use magnetoencephalography and advanced time series analyses to examine these neural dynamics during a visuospatial processing task in a group of HIV-infected patients without HAND (n = 25), patients with HAND (n = 18), and a group of demographically-matched uninfected controls (n = 24). All participants completed a thorough neuropsychological assessment, and underwent magnetoencephalography and structural MRI protocols. In agreement with previous studies, patients with HAND performed significantly worse than HIV-infected patients without HAND and controls on the cognitive task, in terms of increased reaction time and decreased accuracy. Our magnetoencephalography results demonstrated that both spontaneous and neural oscillatory activity within the occipital cortices were affected by HIV infection, and that these patterns predicted behavioural performance (i.e. accuracy) on the task. Specifically, spontaneous neural activity in the alpha (8-16 Hz) and gamma (52-70 Hz) bands during the prestimulus baseline period, as well as oscillatory theta responses (4-8 Hz) during task performance were aberrant in HIV-infected patients, with both spontaneous alpha and oscillatory theta activity significantly predicting accuracy on the task and neuropsychological performance outside of the magnetoencephalography scanner. Importantly, these rhythmic patterns of population-level neural activity also distinguished patients by HAND status, such that spontaneous alpha activity in patients with HAND was elevated relative to HIV-infected patients without HAND and controls. In contrast, HIV-infected patients with and without HAND had increased spontaneous gamma compared to controls. Finally, there was a stepwise decrease in oscillatory theta activity as a function of disease severity, such that the response diminished from controls to patients without HAND to patients with HAND. Interestingly, the strength of the relationship between this theta response and accuracy also dissociated patient groups in a similar manner (controls \textgreater HIV with no HAND \textgreater HIV with HAND), indicating a reduced coupling between neurophysiology and behaviour in HIV-infected patients. This study provides the first neuroimaging evidence of a dissociation between HIV-infected patients with and without HAND, and these findings shed new light on the neural bases of cognitive impairment in HIV infection.
@article{wiesman_aberrant_2018,
	title = {Aberrant occipital dynamics differentiate {HIV}-infected patients with and without cognitive impairment.},
	volume = {141},
	issn = {1460-2156 0006-8950},
	doi = {10.1093/brain/awy097},
	abstract = {Combination antiretroviral therapies have revolutionized the treatment of HIV infection, and many patients now enjoy a lifespan equal to that of the general  population. However, HIV-associated neurocognitive disorders (HAND) remain a  major health concern, with between 30\% and 70\% of all HIV-infected patients  developing cognitive impairments during their life time. One important feature of  HAND is visuo-perceptual deficits, but the systems-level neural dynamics  underlying these impairments are poorly understood. In the current study, we use  magnetoencephalography and advanced time series analyses to examine these neural  dynamics during a visuospatial processing task in a group of HIV-infected  patients without HAND (n = 25), patients with HAND (n = 18), and a group of  demographically-matched uninfected controls (n = 24). All participants completed  a thorough neuropsychological assessment, and underwent magnetoencephalography  and structural MRI protocols. In agreement with previous studies, patients with  HAND performed significantly worse than HIV-infected patients without HAND and  controls on the cognitive task, in terms of increased reaction time and decreased  accuracy. Our magnetoencephalography results demonstrated that both spontaneous  and neural oscillatory activity within the occipital cortices were affected by  HIV infection, and that these patterns predicted behavioural performance (i.e.  accuracy) on the task. Specifically, spontaneous neural activity in the alpha  (8-16 Hz) and gamma (52-70 Hz) bands during the prestimulus baseline period, as  well as oscillatory theta responses (4-8 Hz) during task performance were  aberrant in HIV-infected patients, with both spontaneous alpha and oscillatory  theta activity significantly predicting accuracy on the task and  neuropsychological performance outside of the magnetoencephalography scanner.  Importantly, these rhythmic patterns of population-level neural activity also  distinguished patients by HAND status, such that spontaneous alpha activity in  patients with HAND was elevated relative to HIV-infected patients without HAND  and controls. In contrast, HIV-infected patients with and without HAND had  increased spontaneous gamma compared to controls. Finally, there was a stepwise  decrease in oscillatory theta activity as a function of disease severity, such  that the response diminished from controls to patients without HAND to patients  with HAND. Interestingly, the strength of the relationship between this theta  response and accuracy also dissociated patient groups in a similar manner  (controls {\textgreater} HIV with no HAND {\textgreater} HIV with HAND), indicating a reduced coupling  between neurophysiology and behaviour in HIV-infected patients. This study  provides the first neuroimaging evidence of a dissociation between HIV-infected  patients with and without HAND, and these findings shed new light on the neural  bases of cognitive impairment in HIV infection.},
	language = {eng},
	number = {6},
	journal = {Brain : a journal of neurology},
	author = {Wiesman, Alex I. and O'Neill, Jennifer and Mills, Mackenzie S. and Robertson, Kevin R. and Fox, Howard S. and Swindells, Susan and Wilson, Tony W.},
	month = jun,
	year = {2018},
	pmid = {29672678},
	pmcid = {PMC5972635},
	note = {Place: England},
	keywords = {*Brain Mapping, Adult, Cognition Disorders/*etiology/*virology, Female, Functional Laterality, HIV Infections/*complications, Humans, Magnetic Resonance Imaging, Magnetoencephalography, Male, Middle Aged, Multivariate Analysis, Neuropsychological Tests, Occipital Lobe/*physiopathology, Perceptual Disorders/*etiology, Photic Stimulation, Time Factors, Visual Perception/physiology},
	pages = {1678--1690},
}

Downloads: 0