Logical Reasoning

PT15 · S3 · Q21 When a person with temporal lobe

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When a person with temporal lobe epilepsy is having an epileptic seizure, part of the brain’s temporal lobe produces abnormal electrical impulses, which can often, but not always, be detected through a test called an electroencephalogram (EEG).

Facts

causal

Someone with TLE is >> abnormal elec impulses having a seizure in temporal lobe

pivot Often, those are detected by an EEG. Sometimes they aren't detected by an EEG.

Setup for Conclusion

Although, a pos EEG detection is a reasonably reliable indicator during a seizure of TLE ....

Evaluate

The completion needs the contrast set up by "although." If a positive reading is reliable for confirming the condition, the contrast should say that a negative reading is not reliable.

And this would make sense, given that EEG can miss seizures ("not always" detected).

Goal

Find an answer that says a negative EEG reading isn't a reliable indicator that the person having a seizure doesn't have TLE.

21.

Of the following, which one logically completes the conclusion above?

  1. a positive reading is just

    Too Strong

    This says a positive reading is reliable for the absence of temporal lobe epilepsy. This fails the "although" structure, because there's no contrast. And it makes no sense: "Although it's reliably indicating you do have TLE, it's also reliably indicating that you don't have TLE."

    6% picked this

  2. a positive reading can also

    Out of Scope

    The stimulus only discusses temporal lobe epilepsy and how EEG handles it. It says nothing about whether the impulses (or EEG positives) might also indicate other forms of epilepsy. We can't conclude this from what's given.

    3% picked this

  3. a positive reading is more

    Unsupported

    The stimulus tells us EEG can't always detect the impulses, which means there can be false negatives. But it doesn't say anything about the relative frequency of false positives vs. false negatives — only that positives are "reasonably reliable" and detection is not guaranteed. Comparing error rates of the two reading types isn't supported.

    1% picked this

  4. Correct

    a negative reading does not

    Why this is right

    This balances out the Although. Although a positive reading reliably means you do have TLE, a negative reading doesn't reliably mean you don't have TLE. This is supported, because EEG can fail to detect the abnormal impulses ("not always" detected), so a negative reading can't rule out temporal lobe epilepsy — the EEG might have just missed it. Positives are evidence in favor; negatives are not strong evidence against.

    Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.

    87% picked this

  5. a negative reading is just

    Reversal / Negation

    This says a negative reading reliably indicates the presence of temporal lobe epilepsy. That's backwards: a negative reading means the impulses weren't detected, which is at best ambiguous (could be no condition, or a missed detection). It can't reliably indicate presence. It would also be nonsensical to say that a positive reading, as well as a negative reading, on an EEG were both reliable indicators that you have TLE. That would be like a pregnancy test where the "+" sign as well as the "-" sign are both indicating that you're pregnant. Mazel tov!

    3% picked this

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