Allan E. Edwards

Visual illusion, tactile sensibility and reaction time under LSD-25.

SummaryA series of standard tasks: reaction times; simple light, simple buzzer, disjunctive light, and discriminative light; warmth detection, two-point discrimination, size constancy, Mueller-Lyer illusion, and color detection, were administered to subjects under LSD-25 and control states. A general impairment of reaction time and skin sensitivity was obtained. Color detection was unaffected and the illusions were enhanced. The data were interpreted as representing the result of damping of somaesthetic sensations and a reduction in visual cues.

The Psychedelics: Love or Hostility Potion?

30 heavy psychedelic users were compared with 30 matched controls using the Rosenzweig and Comrey tests. The drug-dependent group demonstrated aberrant personality traits only with respect to increased Hostility. It appears that this propensity is unrelated to degree of drug dependency and may reflect a predisposing state. People who have difficulty handling their aggressive feelings may tend to become heavy drug users. How this hostility is expressed does appear to change with degree of dependence, becoming more extrapunitive and obstacle dominant as drug dependency increases.

Time perception and hemodialysis.

Subtle alterations in neurological function are often difficult to identify and even harder to quantitate. The identification of a neurotoxic state existing before overt behavioral changes occur has eluded quantification. It was hypothesized that a challenging signal-detection procedure would be used to assess neurological function of dialysis patients and other subjects, the degree of uremic toxicity occuring during an interdialytic interval, and the effects of neuroactive drugs. A vigilance task demanding the detection of an irregularly flashing light from a matrix of regularly flashing lights was administered to 3 groups of 15 men: patients undergoing maintenance hemodialysis, patients with chronic illness and no kidney disease, and healthy subjects. The procedure was found to yield a reliable measure; average test-retest correlation was 0.93, which differentiated not only within the hemodialysis cycle (p less than 0.001), between groups (p less than 0.001), but was also related to the recency of neuroactive drugs ingested (p less than 0.01).

An Automated Branching Device for the Assessment and Training of Visual Discrimination

An automated device for the assessment and training of visual discrimination is described. The device utilizes a juke-box upon which film apparatus is mounted, as a random access slide projector. Filmed stimulus material is placed around the circumference of plastic discs housed in the juke-box and is projected onto a screen in programmed sequences. The device is inexpensive, has a good memory, is electrically controllable, and has a maximum search time of 11 sec. for 2400 chips of film. It has been used successfully in the assessment and training of more than 200 brain-damaged patients.