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Confirmation Of Correlation Between Brain Nerve Conduction Velocity And Intelligence Level In Normal Adults, T. Reed, Philip Vernon, Andrew Johnson Oct 2004

Confirmation Of Correlation Between Brain Nerve Conduction Velocity And Intelligence Level In Normal Adults, T. Reed, Philip Vernon, Andrew Johnson

Andrew M. Johnson

In 1992, Reed and Jensen [Intelligence 16 (1992) 259–272] reported a positive correlation (.26; p=.002; .37 after correcting for restricted intelligence range) between a brain nerve conduction velocity (NCV) and intelligence level in 147 normal male students. In the first follow-up of their study, we report on a study using similar NCV methodologies, but testing both male and female students and using more extensive measures of cognitive abilities. One-hundred eighty-six males and 201 females, aged 18–25 years, were tested in three different NCV conditions and with nine cognitive tests, including Raven Progressive Matrices as used by Reed and Jensen. None …


Screening For Parkinson's Disease With Response Time Batteries: A Pilot Study, Andrew Johnson, Philip Vernon, Quincy Almeida, Linda Grantier, Rene Singarayer, Mandar Jog Sep 2004

Screening For Parkinson's Disease With Response Time Batteries: A Pilot Study, Andrew Johnson, Philip Vernon, Quincy Almeida, Linda Grantier, Rene Singarayer, Mandar Jog

Andrew M. Johnson

Background: Although significant response time deficits (both reaction time and movement time) have been identified in numerous studies of patients with Parkinson's disease (PD), few attempts have been made to evaluate the use of these measures in screening for PD. Methods: Receiver operator characteristic curves were used to identify cutoff scores for a unit-weighted composite of two choice response tasks in a sample of 40 patients and 40 healthy participants. These scores were then cross-validated in an independent sample of 20 patients and 20 healthy participants. Results: The unit-weighted movement time composite demonstrated high sensitivity (90%) and specificity (90%) in …


A Behavior Genetic Investigation Of The Relationship Between Leadership And Personality, Andrew Johnson, Philip Vernon, Julie Harris, Kerry Jang Jan 2004

A Behavior Genetic Investigation Of The Relationship Between Leadership And Personality, Andrew Johnson, Philip Vernon, Julie Harris, Kerry Jang

Andrew M. Johnson

Phenotypic research on leadership style has long considered the importance of individual differences in personality when identifying the behaviors associated with good leaders. Although leadership and many personality traits have been separately shown to be heritable, these constructs have not been examined with genetically informative data to identify common sources of heritability in the two domains. A logical extension to current research, therefore, is to examine the extent to which factors of personality are predictive of leadership dimensions and the extent to which unique genetic contributions to the relationship between personality and leadership style may be identified. Adult twin pairs …


The Genetic Basis Of Substance Abuse: Mediating Effects Of Sensation Seeking, Andrew Johnson, Philip Vernon Dec 2003

The Genetic Basis Of Substance Abuse: Mediating Effects Of Sensation Seeking, Andrew Johnson, Philip Vernon

Andrew M. Johnson

Most modern theories of personality are structured hierarchically, with broad higher-order dimensions predicting narrower trait-level variables. This approach is necessarily reductionist, proposing to summarize the majority of trait-specific variability with a smaller number of larger dimensions. Not surprisingly, therefore, significant research has been directed to determining what might be considered to be the most basic dimensions of personality—both with regards to the identification of how many factors are needed to describe personality, and what these factors might be called (Costa & McCrae 1992a; [29] and [30]; Tupes & Christal 1992; Zuckerman 1992; [121] and [122]. While these omnibus factors of …


Sex Difference In Brain Nerve Conduction Velocity In Normal Humans, T. Reed, Philip Vernon, Andrew Johnson Dec 2003

Sex Difference In Brain Nerve Conduction Velocity In Normal Humans, T. Reed, Philip Vernon, Andrew Johnson

Andrew M. Johnson

Nerve conduction velocity (NCV), the speed at which impulses travel along nerves, has been extensively determined in human peripheral nerves because of its clinical utility. In contrast, almost no studies have been made of human brain NCV. We determined brain NCVs in the visual nerve pathway for 185 male and 200 female university students ages 18-25 years. In each of three independent test conditions, we found that the mean NCV of male students is about 4% faster than in females (P < or = 0.0001 for each condition). These male students also have a shorter reaction time in each of seven …


Visual Inspection Time In Parkinson's Disease: Deficits In Early Stages Of Cognitive Processing, Andrew Johnson, Quincy Almeida, Con Stough, James Thompson, Rene Singarayer, Mandar Jog Dec 2003

Visual Inspection Time In Parkinson's Disease: Deficits In Early Stages Of Cognitive Processing, Andrew Johnson, Quincy Almeida, Con Stough, James Thompson, Rene Singarayer, Mandar Jog

Andrew M. Johnson

Inspection time (IT) is a simple information processing paradigm dependent on a participant's ability to identify physical properties of a stimulus presented for a specified time interval. In contrast with reaction time (RT) studies, the dependent variable of interest in IT is not related to the motoric speed with which the individual is able to respond, but rather the minimum presentation time necessary for participants to reliably identify physical properties of the stimulus. It is well documented that individuals with Parkinson's disease (PD) experience significant impairment on tests of simple RT, but it is unclear whether such deficits can be …