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Chapter 4: Problem 57

Spinal fluid proteins and Alzheimer's \(\quad\) A research study published in 2010 in the Archives of Neurology investigated the relationship between the results of a spinal fluid test and the presence of Alzheimer's disease. The study included 114 patients with normal memories, 200 with memory problems, and 102 with Alzheimer's disease. Each individual's spinal fluid was analyzed to detect the presence of two types of proteins. Almost everyone with Alzheimer's had the proteins in their spinal fluid. Nearly three quarters of the group with memory problems had the proteins, and each such member developed Alzheimer's within five years. About one third of those with normal memories had the proteins, and the researchers suspect that those individuals will develop memory problems and eventually Alzheimer's. a. Identify the explanatory and response variable(s). b. Was this an experimental or nonexperimental study? Why? c. Would it be possible to design this study as an experiment? Explain why or why not.

Short Answer

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a) Explanatory: proteins in spinal fluid; Response: Alzheimer's disease. b) Nonexperimental study. c) Not possible to design as an experiment due to ethical concerns.

Step by step solution

01

Identify the Explanatory Variable

The explanatory variable is the presence of two types of proteins in the spinal fluid of individuals. This is the variable that is being used to explain changes or effects on another variable, which, in this case, is the development of Alzheimer's disease.
02

Identify the Response Variable

The response variable is the presence of Alzheimer's disease or the development of memory problems. This variable responds to changes in the explanatory variable, which is the presence of proteins in the spinal fluid.
03

Determine Study Type for Question (b)

To determine whether the study is experimental or nonexperimental, consider how the data were collected. This study is nonexperimental (observational) because it observes individuals with various memory conditions without manipulating any variables. Participants were not randomly assigned to groups, and no treatments were applied.
04

Evaluate the Possibility of Designing as an Experiment for Question (c)

An experiment would require manipulating the explanatory variable, which in this case would mean controlling or changing the presence of proteins in spinal fluid. This is not feasible or ethical, as you cannot introduce or remove proteins to study their effect without potential harm. Therefore, it is not possible to design this study as an experiment.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Explanatory Variable
In research studies, the explanatory variable is the factor that is hypothesized to influence the outcome or effect being studied. It's an independent variable that we think could cause changes in another variable. In the context of the Alzheimer's study, the explanatory variable is the presence of two specific types of proteins in the spinal fluid. Researchers are interested in understanding how these proteins might affect or be associated with the progression of memory problems or Alzheimer's disease. It's like being the detective piece in a puzzle; by understanding this variable, researchers can make sense of the broader picture in the study.
Response Variable
A response variable, also known as the dependent variable, is the outcome that researchers are interested in observing or predicting. It "responds" to the changes or conditions set by the explanatory variable. In the Alzheimer's study, the response variable is the development of Alzheimer's disease or memory issues in participants. This variable helps researchers assess whether there's a meaningful connection between the spinal fluid proteins and these neurological conditions. Think of it as the result of an equation that researchers are trying to solve using other known values, like the presence of proteins.
Observational Study
An observational study is a research design where researchers observe and analyze outcomes without interfering or manipulating the subjects' environment or variables. This is essential when it's not possible or ethical to alter variables directly. In the given study on Alzheimer's, researchers only collected data from participants without introducing any interventions, such as altering protein levels in the spinal fluid.
  • No random assignment or treatments are applied.
  • Researchers watch and record subject conditions without behavioral intervention.
  • This type of study is crucial for naturally occurring variable relationships.
Observational studies are often used in cases where manipulation could be harmful or unethical, providing crucial insights into real-world phenomena.
Ethical Considerations in Research
Ethical considerations are paramount in designing and conducting research. They ensure the safety and rights of participants while maintaining scientific integrity. In the context of the Alzheimer's study, ethical concerns come into play due to the nature of the variables. Manipulating the explanatory variable, such as introducing or removing proteins in spinal fluid, is not ethical due to potential health risks.
  • Protecting participant well-being is a priority.
  • Researchers must avoid actions that cause harm or unnecessary risk.
  • Informed consent and respect for participants' autonomy are vital.
Researchers must design studies respecting ethical guidelines, balancing the pursuit of knowledge with the responsibility to protect participants.

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