The poor often behave in less capable ways, which can further perpetuate poverty. We hypothesize that poverty directly impedes cognitive function and present two studies that test this hypothesis. First, we experimentally induced thoughts about finances and found that this reduces cognitive performance among poor but not in well-off participants. Second, we examined the cognitive function of farmers over the planting cycle. We found that the same farmer shows diminished cognitive performance before harvest, when poor, as compared with after harvest, when rich. This cannot be explained by differences in time available, nutrition, or work effort. Nor can it be explained with stress: Although farmers do show more stress before harvest, that does not account for diminished cognitive performance. Instead, it appears that poverty itself reduces cognitive capacity. We suggest that this is because poverty-related concerns consume mental resources, leaving less for other tasks. These data provide a previously unexamined perspective and help explain a spectrum of behaviors among the poor. We discuss some implications for poverty policy.

http://science.sciencemag.org/content/sci/341/6149/976.full.pdf

Poverty impedes cognitive function

Evoked potentials in clinical medicine , Evoked potentials in clinical medicine , کتابخانه مرکزی دانشگاه علوم پزشکی ایران

Evoked Potentials in Clinical Medicine

Computer techniques readily extract from the brainwaves an orderly sequence of brain potentials locked in time to sound stimuli. The potentials that appear 8 to 80 msec after the stimulus resemble 3 or 4 cycles of a 40-Hz sine wave; we show here that these waves combined to form a single, stable, composite wave when the sounds are repeated at rates around 40 per sec. This phenomenon, the 40-Hz event-related potential (ERP), displays several properties of theoretical and practical interest. First, it reportedly disappears with surgical anesthesia, and it resembles similar phenomena in the visual and olfactory system, facts which suggest that adequate processing of sensory information may require cyclical brain events in the 30- to 50-Hz range. Second, latency and amplitude measurements on the 40-Hz ERP indicate it may contain useful information on the number and basilar membrane location of the auditory nerve fibers a given tone excites. Third, the response is present at sound intensities very close to normal adult thresholds for the audiometric frequencies, a fact that could have application in clinical hearing testing.

https://www.pnas.org/content/pnas/78/4/2643.full.pdf

A 40-Hz auditory potential recorded from the human scalp

Background and Methods. The use of corticosteroids to treat optic neuritis is controversial. At 15 clinical centers, we randomly assigned 457 patients with acute optic neuritis to receive oral prednisone (1 mg per kilogram of body weight per day) for 14 days; intravenous methylprednisolone (1 g per day) for 3 days, followed by oral prednisone (1 mg per kilogram per day) for 11 days; or oral placebo for 14 days. Visual function was assessed over a six-month follow-up period. Results. Visual function recovered faster in the group receiving intravenous methylprednisolone than in the placebo group; this was particularly true for the reversal of visual-field defects (P = 0.0001). Although the differences between the groups decreased with time, at six months the group that received intravenous methylprednisolone still had slightly better visual fields (P = 0.054), contrast sensitivity (P = 0.026), and color vision (P = 0.033) but not better visual acuity (P = 0.66). The outcome in the oral-prednisone group did ...

https://www.nejm.org/doi/pdf/10.1056/NEJM199202273260901

A Randomized, Controlled Trial of Corticosteroids in the Treatment of Acute Optic Neuritis

Computer techniques readily extract from the brainwaves an orderly sequence of brain potentials locked in time to sound stimuli. The potentials that appear 8 to 80 msec after the stimulus resemble 3 or 4 cycles of a 40-Hz sine wave; we show here that these waves combine to form a single, stable, composite wave when the sounds are repeated at rates around 40 per sec. This phenomenon, the 40-Hz event-related potential (ERP), displays several properties of theoretical and practical interest. First, it reportedly disappears with surgical anesthesia, and it resembles similar phenomena in the visual and olfactory system, facts which suggest that adequate processing of sensory information may re- quire cyclical brain events in the 30- to 50-Hz range. Second, la- tency and amplitude measurements on the 40-Hz ERP indicate it may contain useful information on the number and basilar mem- brane location of the auditory nerve fibers a given tone excites. Third, the response is present at sound intensities very close to normal adult thresholds for the audiometric frequencies, a fact that could have application in clinical hearing testing. When a person cannot, or will not, tell the interested observer what he hears, it has in the past been difficult to obtain trust- worthy measurements of hearing. The recent advent of elec- trophysiological tests of hearing and comprehension has radi- cally changed this situation (1, 2). In these tests one records the listener's brainwaves while sounds are presented via loud- speaker or earphones; the sounds generate electric responses within the brain that are readily extracted by a computer (Fig. lA). The resulting sequence of brain potentials, known as event- related potentials (ERPs), begins within a millisecond or two of stimulus delivery and continues thereafter for a half second or more. We deal here with the series ofwaves that appears 8-80 msec after stimulus delivery, the so-called middle-latency re- sponse (MLR). We report a way to extract it from the brain- waves, describe several properties of the response so obtained, and, among other things, show it to predict adult auditory thresholds in a highly reliable manner.

A 40-Hz auditory potential recorded from the human scalp (hearing tests/auditory evoked potentials/40-Hz brain waves/sensory processing)

The incidence of HL—A3 among 94 patients with a diagnosis of multiple sclerosis (MS) was significantly higher than for 871 normal persons. In addition, some increase in Te58 and decrease in HL—A2 and Te60 frequencies was noted. The well-known higher incidence of MS among Caucasians than among Orientals is paralleled by the higher incidence of HL—A3 and Te58 among Caucasians and a lower incidence of Te60.

Multiple Sclerosis: Association with HL—A3

Cooperative study in the evaluation of therapy in multiple sclerosis. ACTH vs. placebo--final report.

Neuropsychological assessment of monolingual Spanish-speaking people in the United States is both a common practice and an ethical dilemma Lack of appropriate tests, the absence of norms, use of interpreters, and the multiplicity of in-house translations of commonly used measures add to the problem of accurate assessment This paper helps address the lack of appropriate measures for the neuropsychological assessment of Latinos in the United States by providing a standardization of the Neuropsychological Screening Battery for Hispanics (NeSBHIS) Normative data on a sample of 300 Hispanic subjects stratified by gender, age, and education are provided Current results reveal that not one measure of cognitive functioning is free from education effects Both nonverbal measures and psychomotor speed measures were highly related to education Age effects were noted on measures of psychomotor speed, visuospatial reasoning, and visuoconstructive skills Gender effects were found on measures of psychomotor speed and language, with males achieving higher scores than females The limitations of the current findings are considered Further research for the validation of the NeSBHIS with clinical populations, as well as further normative data collection at the national and international levels, is needed

Normative data stratified by age and education for the Neuropsychological Screening Battery for Hispanics (NeSBHIS): Initial report.

IT IS GENERALLY ACCEPTED that symptoms in multiple sclerosis are produced by blocked or impaired nerve conduction across areas of demyelination. Charcot' was the first to suggest such impaired or slowed conduction as the basic pathophysiology of this disease, yet few investigators have attempted to demonstrate this mechanism in man or in lower animals. McDonald,2 Meyer? and Hall,4 each using different methods to produce experimental demyelination of central and peripheral axons, have only recently derived experimental evidence that supports Charcot's earlier speculations. Our own interests have been with the use of the somatosensory cortical evoked response in multiple sclerosis patients. I t has been previously shown and confirmed in our own laboratory that the somatosensory evoked response is abnormal in disease states in which there is impairment of position or vibration sense or both. Since these deficits are frequently present in multiple sclerosis, it was felt appropriate to use this type of evoked response as a means of assessing subcortical conduction phenomena in these patients.

Somatosensory evoked responses in multiple sclerosis patients with varying sensory loss

FOR SOME PERIOD OF TIME, our laboratory has been interested in neurophysiological correlates of multiple sclerosis (MS) Although early work centered about evoked cortical response studies, more recently we have become interested in simple, centrally mediated reflex arcs that do not require averaging methods for detection of the evoked response. One such easily assessed pathway is that for the orbicularis oculi reflex, as generated by stimulation of the supraorbital nerve and detected by reflex contraction of the orbicularis oculi muscle. While several previous studies have demonstrated changes in this reflex with various pontine lesions, only one has dealt specifically with multiple sclerosis.3-7 It was anticipated that continued study of such a relatively simple pathway would further our understanding of the nature of neuronal conduction in human demyelinating disease.

Norman S. Namerow

Papers

Multiple Sclerosis: Association with HL—A3

Cooperative study in the evaluation of therapy in multiple sclerosis. ACTH vs. placebo--final report.

Normative data stratified by age and education for the Neuropsychological Screening Battery for Hispanics (NeSBHIS): Initial report.

Somatosensory evoked responses in multiple sclerosis patients with varying sensory loss

The orbicularis oculi reflex in multiple sclerosis.