New and Noteworthy Information—January 2017

Students who played varsity high school football between 1956 and 1970 do not have an increased risk of neurodegenerative diseases, compared with athletes engaged in other varsity sports, according to a study published online ahead of print December 12, 2016, in Mayo Clinic Proceedings. Researchers identified 296 male varsity football players in public high schools in Rochester, Minnesota, and 190 male varsity swimmers, wrestlers, and basketball players. Using records from the Rochester Epidemiology Project, investigators ascertained the incidence of late-life neurodegenerative diseases. Football players had an increased risk of medically documented head trauma, especially if they played football for more than one year. Compared with other athletes, football players did not have an increased risk of neurodegenerative disease overall, nor an increased risk of dementia, parkinsonism, or amyotrophic lateral sclerosis.
 
Antipsychotic drug use is associated with a 60% increased risk of mortality among persons with Alzheimer's disease, according to a study published online ahead of print December 5, 2016, in the Journal of Alzheimer's Disease. Researchers examined data from the MEDALZ study for 70,718 people who were newly diagnosed with Alzheimer's disease in Finland from 2005 to 2011. Death, excluding death from cancer, was extracted from the Causes of Death Register. Incident antipsychotic use was compared with time without antipsychotics using Cox proportional hazard models. The absolute difference in mortality rate was 4.58 deaths per 100 person-years. The risk of mortality was increased from the first days of antipsychotic use and attenuated gradually. Antipsychotic polypharmacy was associated with an almost doubled risk of mortality, compared with monotherapy.  

A disruption of structural connections in a brain network contributes to cognitive deficits in patients with Parkinson's disease, according to a study published online ahead of print December 7, 2016, in Radiology. The structural brain connectomes of 170 patients with Parkinson's disease and 41 healthy controls were obtained with deterministic diffusion-tensor tractography. Patients with Parkinson's disease and mild cognitive impairment (MCI) had global network alterations, compared with controls and patients with Parkinson's disease without MCI. Relative to controls, patients with Parkinson's disease and MCI had a large basal ganglia and frontoparietal network with decreased fractional anisotropy in the right hemisphere and a subnetwork with increased mean diffusivity involving similar regions bilaterally. Compared with patients with Parkinson's disease without MCI, people with Parkinson's disease and MCI had networks with decreased fractional anisotropy.

 
A proposed diagnostic algorithm for sporadic Creutzfeldt-Jakob disease combines CSF and olfactory mucosa real-time quaking-induced conversion testing to provide approximately 100% sensitivity and specificity in the clinical phase of the disease, according to a study published online ahead of print December 12, 2016, in JAMA Neurology. Among the 86 patients included in this analysis, 61 patients with sporadic Creutzfeldt-Jakob disease had positive real-time quaking-induced conversion findings using olfactory mucosa, CSF samples, or both, for an overall real-time quaking-induced conversion sensitivity of 100%. All patients with a final diagnosis of nonprion disease had negative real-time quaking-induced conversion findings, for 100% specificity. Of eight symptomatic patients with various mutations causing Creutzfeldt-Jakob disease or Gerstmann-Sträussler-Scheinker syndrome, six had positive and two had negative real-time quaking-induced conversion findings, for a sensitivity of 75%.

 
CSF autotaxin may be a useful biomarker of dysmetabolism for examining risk for and outcomes of Alzheimer's disease, according to research published December 1, 2016, in the Journal of Alzheimer's Disease. Investigators studied 287 participants in the Alzheimer's Disease Neuroimaging Initiative, including 86 cognitively normal participants, 135 participants with mild cognitive impairment (MCI), and 66 participants with Alzheimer's disease. Autotaxin levels were significantly higher in patients with MCI and those with Alzheimer's disease. Each point increase in log-based autotaxin corresponded to a 3.5- to 5-times higher likelihood of having MCI and Alzheimer's disease, respectively. Higher autotaxin in Alzheimer's disease predicted hypometabolism in the medial temporal lobe and prefrontal cortex, and worse performance on executive function and memory factors. Autotaxin was associated with decreased cortical thickness in prefrontal cortex areas.

 
Marital history is significantly associated with survival after stroke, according to a study published December 14, 2016, in the Journal of the American Heart Association. Data from a nationally representative sample of 2,351 older adults who experienced a stroke were used to examine whether and to what extent current marital status and past marital losses were associated with risks of dying after the onset of disease. Results showed that the risks of dying following a stroke were significantly higher among people who were never married, remarried, divorced, and widowed, relative to those who remained continuously married. Researchers also found that having multiple marital losses was especially detrimental to survival, regardless of current marital status and accounting for multiple socioeconomic, psychosocial, behavioral, and physiologic risk factors.

 
Prefrontal brain activity levels during a cognitively demanding walking condition predict falls in high-functioning senior citizens, according to a study published online ahead of print December 7, 2016, in Neurology. Researchers examined 166 people with a mean age of 75 with functional near-infrared spectroscopy during motor, cognitive, and combined motor and cognitive tasks. Incident falls were prospectively assessed during a 50-month study period. During a mean follow-up of 33.9 months, 116 falls occurred. Higher levels of prefrontal cortical activation during the dual-task walking condition predicted falls. Neither behavioral outcomes on the dual task nor brain activation patterns on the single tasks predicted falls in this high-functioning sample. The results remained robust after accounting for multiple confounders, cognitive status, slow gait, previous falls, and frailty.

 
Localized brain injury and repair, indicated by higher translocator protein 18 kDa signal and white matter changes, may be associated with National Football League (NFL) play, according to a study published online ahead of print November 28, 2016, in JAMA Neurology. This cross-sectional, case-control study included young active or former NFL players recruited from across the United States and 16 age-, sex-, highest educational level-, and BMI-matched control participants. Researchers used [¹¹C]DPA-713 PET data and other imaging data from 12 active or former NFL players and 11 matched control participants. The NFL players showed higher total distribution volume in eight of 12 brain regions examined. Investigators also observed limited change in white matter fractional anisotropy and mean diffusivity in 13 players, compared with 15 control participants.  

 
Exposure to maternal rheumatoid arthritis is associated with an increased risk of childhood epilepsy, while exposure to paternal rheumatoid arthritis is not, according to a study published December 13, 2016, in Neurology. Researchers performed a nationwide cohort study of 1,917,723 people that were born between 1977 and 2008. Compared with unexposed children, children exposed to maternal rheumatoid arthritis had an increased risk of early and late childhood epilepsy, while children exposed to maternal rheumatoid arthritis had no increased risk of epilepsy in adolescence and adulthood. Paternal rheumatoid arthritis was not associated with an overall risk of epilepsy in the offspring or at any age. Children exposed to maternal rheumatoid arthritis in utero had a more pronounced increased risk of early childhood epilepsy than children of mothers who were diagnosed with rheumatoid arthritis after childbirth.

 
Having surgery may be linked to developing Guillain-Barré syndrome for people with cancer or autoimmune disorders, according to a study published online ahead of print November 23, 2016, in Neurology Clinical Practice. Researchers retrospectively reviewed consecutive patients diagnosed with Guillain-Barré syndrome within eight weeks of a surgical procedure between January 1995 and June 2014. Of the 208 people treated for Guillain-Barré syndrome, 31 people developed the syndrome within eight weeks of having a surgical procedure. People who had had cancer within the previous six months were seven times more likely to develop Guillain-Barré syndrome after surgery than people who had not had cancer. People who had pre-existing autoimmune disorders were five times more likely to develop Guillain-Barré syndrome after surgery than those without autoimmune disorders.

 
Patients with Parkinson's disease and orthostatic hypotension have transient, posture-mediated changes in cognition, according to a study published online ahead of print November 30, 2016, in Neurology. To investigate the relation between orthostatic hypotension and posture-mediated cognitive impairment in Parkinson disease, researchers used a cross-sectional and within-group design. Participants included 18 patients with Parkinson's disease and orthostatic hypotension, 19 patients with Parkinson's disease but without orthostatic hypotension, and 18 healthy controls. Participants underwent neuropsychologic tests in the supine and upright-tilted positions. When relative performances were compared with each other, postural changes had no significant impact on participants with Parkinson's disease but without orthostatic hypotension, compared with the control group. Participants with Parkinson's disease and orthostatic hypotension, however, were more susceptible to posture-related impairment on several tests.  

Low concentrations of neonatal vitamin D are associated with an increased risk of multiple sclerosis (MS), according to a study published online ahead of print November 30, 2016, in Neurology. Researchers conducted a matched case-control study. Dried blood spots samples from 521 patients with MS were identified in the Danish Newborn Screening Biobank. For every patient with MS, one to two controls with the same sex and birth date were retrieved from the Biobank. Lower levels of 25-hydroxyvitamin D in neonates were associated with an increased risk of MS. In the analysis by quintiles, MS risk was highest among individuals in the bottom quintile and lowest among those in the top quintile of 25-hydroxyvitamin D, with an odds ratio for top versus bottom of 0.53. 

 
Children exposed to valproate in the womb are at an increased risk of having a malformation at birth, and the dose of valproate that the child is exposed to determines the level of risk, according to a study published November 7, 2016, in the Cochrane Database of Systematic Reviews. Researchers analyzed 50 studies, with 31 contributing to a meta-analysis. Children exposed to valproate were at a higher risk of malformation, compared with children born to women without epilepsy and to women with untreated epilepsy. Investigators found significantly higher rates of specific malformations associating phenobarbital exposure with cardiac malformations and valproate exposure with neural tube, cardiac, orofacial, craniofacial, skeletal, and limb malformations, compared with other antiepileptic drugs. Dose of exposure mediated the risk of malformation following valproate exposure.

—Kimberly Williams

Students who played varsity high school football between 1956 and 1970 do not have an increased risk of neurodegenerative diseases, compared with athletes engaged in other varsity sports, according to a study published online ahead of print December 12, 2016, in Mayo Clinic Proceedings. Researchers identified 296 male varsity football players in public high schools in Rochester, Minnesota, and 190 male varsity swimmers, wrestlers, and basketball players. Using records from the Rochester Epidemiology Project, investigators ascertained the incidence of late-life neurodegenerative diseases. Football players had an increased risk of medically documented head trauma, especially if they played football for more than one year. Compared with other athletes, football players did not have an increased risk of neurodegenerative disease overall, nor an increased risk of dementia, parkinsonism, or amyotrophic lateral sclerosis.
 
Antipsychotic drug use is associated with a 60% increased risk of mortality among persons with Alzheimer's disease, according to a study published online ahead of print December 5, 2016, in the Journal of Alzheimer's Disease. Researchers examined data from the MEDALZ study for 70,718 people who were newly diagnosed with Alzheimer's disease in Finland from 2005 to 2011. Death, excluding death from cancer, was extracted from the Causes of Death Register. Incident antipsychotic use was compared with time without antipsychotics using Cox proportional hazard models. The absolute difference in mortality rate was 4.58 deaths per 100 person-years. The risk of mortality was increased from the first days of antipsychotic use and attenuated gradually. Antipsychotic polypharmacy was associated with an almost doubled risk of mortality, compared with monotherapy.  

A disruption of structural connections in a brain network contributes to cognitive deficits in patients with Parkinson's disease, according to a study published online ahead of print December 7, 2016, in Radiology. The structural brain connectomes of 170 patients with Parkinson's disease and 41 healthy controls were obtained with deterministic diffusion-tensor tractography. Patients with Parkinson's disease and mild cognitive impairment (MCI) had global network alterations, compared with controls and patients with Parkinson's disease without MCI. Relative to controls, patients with Parkinson's disease and MCI had a large basal ganglia and frontoparietal network with decreased fractional anisotropy in the right hemisphere and a subnetwork with increased mean diffusivity involving similar regions bilaterally. Compared with patients with Parkinson's disease without MCI, people with Parkinson's disease and MCI had networks with decreased fractional anisotropy.

 
A proposed diagnostic algorithm for sporadic Creutzfeldt-Jakob disease combines CSF and olfactory mucosa real-time quaking-induced conversion testing to provide approximately 100% sensitivity and specificity in the clinical phase of the disease, according to a study published online ahead of print December 12, 2016, in JAMA Neurology. Among the 86 patients included in this analysis, 61 patients with sporadic Creutzfeldt-Jakob disease had positive real-time quaking-induced conversion findings using olfactory mucosa, CSF samples, or both, for an overall real-time quaking-induced conversion sensitivity of 100%. All patients with a final diagnosis of nonprion disease had negative real-time quaking-induced conversion findings, for 100% specificity. Of eight symptomatic patients with various mutations causing Creutzfeldt-Jakob disease or Gerstmann-Sträussler-Scheinker syndrome, six had positive and two had negative real-time quaking-induced conversion findings, for a sensitivity of 75%.

 
CSF autotaxin may be a useful biomarker of dysmetabolism for examining risk for and outcomes of Alzheimer's disease, according to research published December 1, 2016, in the Journal of Alzheimer's Disease. Investigators studied 287 participants in the Alzheimer's Disease Neuroimaging Initiative, including 86 cognitively normal participants, 135 participants with mild cognitive impairment (MCI), and 66 participants with Alzheimer's disease. Autotaxin levels were significantly higher in patients with MCI and those with Alzheimer's disease. Each point increase in log-based autotaxin corresponded to a 3.5- to 5-times higher likelihood of having MCI and Alzheimer's disease, respectively. Higher autotaxin in Alzheimer's disease predicted hypometabolism in the medial temporal lobe and prefrontal cortex, and worse performance on executive function and memory factors. Autotaxin was associated with decreased cortical thickness in prefrontal cortex areas.

 
Marital history is significantly associated with survival after stroke, according to a study published December 14, 2016, in the Journal of the American Heart Association. Data from a nationally representative sample of 2,351 older adults who experienced a stroke were used to examine whether and to what extent current marital status and past marital losses were associated with risks of dying after the onset of disease. Results showed that the risks of dying following a stroke were significantly higher among people who were never married, remarried, divorced, and widowed, relative to those who remained continuously married. Researchers also found that having multiple marital losses was especially detrimental to survival, regardless of current marital status and accounting for multiple socioeconomic, psychosocial, behavioral, and physiologic risk factors.

 
Prefrontal brain activity levels during a cognitively demanding walking condition predict falls in high-functioning senior citizens, according to a study published online ahead of print December 7, 2016, in Neurology. Researchers examined 166 people with a mean age of 75 with functional near-infrared spectroscopy during motor, cognitive, and combined motor and cognitive tasks. Incident falls were prospectively assessed during a 50-month study period. During a mean follow-up of 33.9 months, 116 falls occurred. Higher levels of prefrontal cortical activation during the dual-task walking condition predicted falls. Neither behavioral outcomes on the dual task nor brain activation patterns on the single tasks predicted falls in this high-functioning sample. The results remained robust after accounting for multiple confounders, cognitive status, slow gait, previous falls, and frailty.

 
Localized brain injury and repair, indicated by higher translocator protein 18 kDa signal and white matter changes, may be associated with National Football League (NFL) play, according to a study published online ahead of print November 28, 2016, in JAMA Neurology. This cross-sectional, case-control study included young active or former NFL players recruited from across the United States and 16 age-, sex-, highest educational level-, and BMI-matched control participants. Researchers used [¹¹C]DPA-713 PET data and other imaging data from 12 active or former NFL players and 11 matched control participants. The NFL players showed higher total distribution volume in eight of 12 brain regions examined. Investigators also observed limited change in white matter fractional anisotropy and mean diffusivity in 13 players, compared with 15 control participants.  

 
Exposure to maternal rheumatoid arthritis is associated with an increased risk of childhood epilepsy, while exposure to paternal rheumatoid arthritis is not, according to a study published December 13, 2016, in Neurology. Researchers performed a nationwide cohort study of 1,917,723 people that were born between 1977 and 2008. Compared with unexposed children, children exposed to maternal rheumatoid arthritis had an increased risk of early and late childhood epilepsy, while children exposed to maternal rheumatoid arthritis had no increased risk of epilepsy in adolescence and adulthood. Paternal rheumatoid arthritis was not associated with an overall risk of epilepsy in the offspring or at any age. Children exposed to maternal rheumatoid arthritis in utero had a more pronounced increased risk of early childhood epilepsy than children of mothers who were diagnosed with rheumatoid arthritis after childbirth.

 
Having surgery may be linked to developing Guillain-Barré syndrome for people with cancer or autoimmune disorders, according to a study published online ahead of print November 23, 2016, in Neurology Clinical Practice. Researchers retrospectively reviewed consecutive patients diagnosed with Guillain-Barré syndrome within eight weeks of a surgical procedure between January 1995 and June 2014. Of the 208 people treated for Guillain-Barré syndrome, 31 people developed the syndrome within eight weeks of having a surgical procedure. People who had had cancer within the previous six months were seven times more likely to develop Guillain-Barré syndrome after surgery than people who had not had cancer. People who had pre-existing autoimmune disorders were five times more likely to develop Guillain-Barré syndrome after surgery than those without autoimmune disorders.

 
Patients with Parkinson's disease and orthostatic hypotension have transient, posture-mediated changes in cognition, according to a study published online ahead of print November 30, 2016, in Neurology. To investigate the relation between orthostatic hypotension and posture-mediated cognitive impairment in Parkinson disease, researchers used a cross-sectional and within-group design. Participants included 18 patients with Parkinson's disease and orthostatic hypotension, 19 patients with Parkinson's disease but without orthostatic hypotension, and 18 healthy controls. Participants underwent neuropsychologic tests in the supine and upright-tilted positions. When relative performances were compared with each other, postural changes had no significant impact on participants with Parkinson's disease but without orthostatic hypotension, compared with the control group. Participants with Parkinson's disease and orthostatic hypotension, however, were more susceptible to posture-related impairment on several tests.  

Low concentrations of neonatal vitamin D are associated with an increased risk of multiple sclerosis (MS), according to a study published online ahead of print November 30, 2016, in Neurology. Researchers conducted a matched case-control study. Dried blood spots samples from 521 patients with MS were identified in the Danish Newborn Screening Biobank. For every patient with MS, one to two controls with the same sex and birth date were retrieved from the Biobank. Lower levels of 25-hydroxyvitamin D in neonates were associated with an increased risk of MS. In the analysis by quintiles, MS risk was highest among individuals in the bottom quintile and lowest among those in the top quintile of 25-hydroxyvitamin D, with an odds ratio for top versus bottom of 0.53. 

 
Children exposed to valproate in the womb are at an increased risk of having a malformation at birth, and the dose of valproate that the child is exposed to determines the level of risk, according to a study published November 7, 2016, in the Cochrane Database of Systematic Reviews. Researchers analyzed 50 studies, with 31 contributing to a meta-analysis. Children exposed to valproate were at a higher risk of malformation, compared with children born to women without epilepsy and to women with untreated epilepsy. Investigators found significantly higher rates of specific malformations associating phenobarbital exposure with cardiac malformations and valproate exposure with neural tube, cardiac, orofacial, craniofacial, skeletal, and limb malformations, compared with other antiepileptic drugs. Dose of exposure mediated the risk of malformation following valproate exposure.

—Kimberly Williams

Students who played varsity high school football between 1956 and 1970 do not have an increased risk of neurodegenerative diseases, compared with athletes engaged in other varsity sports, according to a study published online ahead of print December 12, 2016, in Mayo Clinic Proceedings. Researchers identified 296 male varsity football players in public high schools in Rochester, Minnesota, and 190 male varsity swimmers, wrestlers, and basketball players. Using records from the Rochester Epidemiology Project, investigators ascertained the incidence of late-life neurodegenerative diseases. Football players had an increased risk of medically documented head trauma, especially if they played football for more than one year. Compared with other athletes, football players did not have an increased risk of neurodegenerative disease overall, nor an increased risk of dementia, parkinsonism, or amyotrophic lateral sclerosis.
 
Antipsychotic drug use is associated with a 60% increased risk of mortality among persons with Alzheimer's disease, according to a study published online ahead of print December 5, 2016, in the Journal of Alzheimer's Disease. Researchers examined data from the MEDALZ study for 70,718 people who were newly diagnosed with Alzheimer's disease in Finland from 2005 to 2011. Death, excluding death from cancer, was extracted from the Causes of Death Register. Incident antipsychotic use was compared with time without antipsychotics using Cox proportional hazard models. The absolute difference in mortality rate was 4.58 deaths per 100 person-years. The risk of mortality was increased from the first days of antipsychotic use and attenuated gradually. Antipsychotic polypharmacy was associated with an almost doubled risk of mortality, compared with monotherapy.  

A disruption of structural connections in a brain network contributes to cognitive deficits in patients with Parkinson's disease, according to a study published online ahead of print December 7, 2016, in Radiology. The structural brain connectomes of 170 patients with Parkinson's disease and 41 healthy controls were obtained with deterministic diffusion-tensor tractography. Patients with Parkinson's disease and mild cognitive impairment (MCI) had global network alterations, compared with controls and patients with Parkinson's disease without MCI. Relative to controls, patients with Parkinson's disease and MCI had a large basal ganglia and frontoparietal network with decreased fractional anisotropy in the right hemisphere and a subnetwork with increased mean diffusivity involving similar regions bilaterally. Compared with patients with Parkinson's disease without MCI, people with Parkinson's disease and MCI had networks with decreased fractional anisotropy.

 
A proposed diagnostic algorithm for sporadic Creutzfeldt-Jakob disease combines CSF and olfactory mucosa real-time quaking-induced conversion testing to provide approximately 100% sensitivity and specificity in the clinical phase of the disease, according to a study published online ahead of print December 12, 2016, in JAMA Neurology. Among the 86 patients included in this analysis, 61 patients with sporadic Creutzfeldt-Jakob disease had positive real-time quaking-induced conversion findings using olfactory mucosa, CSF samples, or both, for an overall real-time quaking-induced conversion sensitivity of 100%. All patients with a final diagnosis of nonprion disease had negative real-time quaking-induced conversion findings, for 100% specificity. Of eight symptomatic patients with various mutations causing Creutzfeldt-Jakob disease or Gerstmann-Sträussler-Scheinker syndrome, six had positive and two had negative real-time quaking-induced conversion findings, for a sensitivity of 75%.

 
CSF autotaxin may be a useful biomarker of dysmetabolism for examining risk for and outcomes of Alzheimer's disease, according to research published December 1, 2016, in the Journal of Alzheimer's Disease. Investigators studied 287 participants in the Alzheimer's Disease Neuroimaging Initiative, including 86 cognitively normal participants, 135 participants with mild cognitive impairment (MCI), and 66 participants with Alzheimer's disease. Autotaxin levels were significantly higher in patients with MCI and those with Alzheimer's disease. Each point increase in log-based autotaxin corresponded to a 3.5- to 5-times higher likelihood of having MCI and Alzheimer's disease, respectively. Higher autotaxin in Alzheimer's disease predicted hypometabolism in the medial temporal lobe and prefrontal cortex, and worse performance on executive function and memory factors. Autotaxin was associated with decreased cortical thickness in prefrontal cortex areas.

 
Marital history is significantly associated with survival after stroke, according to a study published December 14, 2016, in the Journal of the American Heart Association. Data from a nationally representative sample of 2,351 older adults who experienced a stroke were used to examine whether and to what extent current marital status and past marital losses were associated with risks of dying after the onset of disease. Results showed that the risks of dying following a stroke were significantly higher among people who were never married, remarried, divorced, and widowed, relative to those who remained continuously married. Researchers also found that having multiple marital losses was especially detrimental to survival, regardless of current marital status and accounting for multiple socioeconomic, psychosocial, behavioral, and physiologic risk factors.

 
Prefrontal brain activity levels during a cognitively demanding walking condition predict falls in high-functioning senior citizens, according to a study published online ahead of print December 7, 2016, in Neurology. Researchers examined 166 people with a mean age of 75 with functional near-infrared spectroscopy during motor, cognitive, and combined motor and cognitive tasks. Incident falls were prospectively assessed during a 50-month study period. During a mean follow-up of 33.9 months, 116 falls occurred. Higher levels of prefrontal cortical activation during the dual-task walking condition predicted falls. Neither behavioral outcomes on the dual task nor brain activation patterns on the single tasks predicted falls in this high-functioning sample. The results remained robust after accounting for multiple confounders, cognitive status, slow gait, previous falls, and frailty.

 
Localized brain injury and repair, indicated by higher translocator protein 18 kDa signal and white matter changes, may be associated with National Football League (NFL) play, according to a study published online ahead of print November 28, 2016, in JAMA Neurology. This cross-sectional, case-control study included young active or former NFL players recruited from across the United States and 16 age-, sex-, highest educational level-, and BMI-matched control participants. Researchers used [¹¹C]DPA-713 PET data and other imaging data from 12 active or former NFL players and 11 matched control participants. The NFL players showed higher total distribution volume in eight of 12 brain regions examined. Investigators also observed limited change in white matter fractional anisotropy and mean diffusivity in 13 players, compared with 15 control participants.  

 
Exposure to maternal rheumatoid arthritis is associated with an increased risk of childhood epilepsy, while exposure to paternal rheumatoid arthritis is not, according to a study published December 13, 2016, in Neurology. Researchers performed a nationwide cohort study of 1,917,723 people that were born between 1977 and 2008. Compared with unexposed children, children exposed to maternal rheumatoid arthritis had an increased risk of early and late childhood epilepsy, while children exposed to maternal rheumatoid arthritis had no increased risk of epilepsy in adolescence and adulthood. Paternal rheumatoid arthritis was not associated with an overall risk of epilepsy in the offspring or at any age. Children exposed to maternal rheumatoid arthritis in utero had a more pronounced increased risk of early childhood epilepsy than children of mothers who were diagnosed with rheumatoid arthritis after childbirth.

 
Having surgery may be linked to developing Guillain-Barré syndrome for people with cancer or autoimmune disorders, according to a study published online ahead of print November 23, 2016, in Neurology Clinical Practice. Researchers retrospectively reviewed consecutive patients diagnosed with Guillain-Barré syndrome within eight weeks of a surgical procedure between January 1995 and June 2014. Of the 208 people treated for Guillain-Barré syndrome, 31 people developed the syndrome within eight weeks of having a surgical procedure. People who had had cancer within the previous six months were seven times more likely to develop Guillain-Barré syndrome after surgery than people who had not had cancer. People who had pre-existing autoimmune disorders were five times more likely to develop Guillain-Barré syndrome after surgery than those without autoimmune disorders.

 
Patients with Parkinson's disease and orthostatic hypotension have transient, posture-mediated changes in cognition, according to a study published online ahead of print November 30, 2016, in Neurology. To investigate the relation between orthostatic hypotension and posture-mediated cognitive impairment in Parkinson disease, researchers used a cross-sectional and within-group design. Participants included 18 patients with Parkinson's disease and orthostatic hypotension, 19 patients with Parkinson's disease but without orthostatic hypotension, and 18 healthy controls. Participants underwent neuropsychologic tests in the supine and upright-tilted positions. When relative performances were compared with each other, postural changes had no significant impact on participants with Parkinson's disease but without orthostatic hypotension, compared with the control group. Participants with Parkinson's disease and orthostatic hypotension, however, were more susceptible to posture-related impairment on several tests.  

Low concentrations of neonatal vitamin D are associated with an increased risk of multiple sclerosis (MS), according to a study published online ahead of print November 30, 2016, in Neurology. Researchers conducted a matched case-control study. Dried blood spots samples from 521 patients with MS were identified in the Danish Newborn Screening Biobank. For every patient with MS, one to two controls with the same sex and birth date were retrieved from the Biobank. Lower levels of 25-hydroxyvitamin D in neonates were associated with an increased risk of MS. In the analysis by quintiles, MS risk was highest among individuals in the bottom quintile and lowest among those in the top quintile of 25-hydroxyvitamin D, with an odds ratio for top versus bottom of 0.53. 

 
Children exposed to valproate in the womb are at an increased risk of having a malformation at birth, and the dose of valproate that the child is exposed to determines the level of risk, according to a study published November 7, 2016, in the Cochrane Database of Systematic Reviews. Researchers analyzed 50 studies, with 31 contributing to a meta-analysis. Children exposed to valproate were at a higher risk of malformation, compared with children born to women without epilepsy and to women with untreated epilepsy. Investigators found significantly higher rates of specific malformations associating phenobarbital exposure with cardiac malformations and valproate exposure with neural tube, cardiac, orofacial, craniofacial, skeletal, and limb malformations, compared with other antiepileptic drugs. Dose of exposure mediated the risk of malformation following valproate exposure.

—Kimberly Williams