ECG will take place during screening visit.

DKEFS Color-Word Interference Test (CWIT) Inhibition Switching scores was used to measure the cognitive flexibility component of executive function. The CWIT is scored by time to complete plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive flexibility.

DKEFS CWIT scores was used to measure the inhibition component of executive function. The CWIT is scored by time to complete plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior inhibition.

DKEFS Letter Fluency Task will be used to assess the verbal functioning cognitive control ability component of executive function. Scores are derived from the number of unique, correct words. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior verbal functioning cognitive control ability.

The grooved pegboard test is a manipulative dexterity task that assesses psychomotor speed, fine motor control, and rapid-visual motor coordination. Participants were asked to insert 25 grooved pegs into holes within the given time limit up to 300 seconds (the score upper limit is thus 300). Time taken to complete the test has been found to be inversely correlated with cognitive ability; therefore, a higher score represents an inferior score. Wilcoxon rank-sum test was used to examine differences between groups.

DKEFS Category Fluency scores were used to measure cognitive control of verbal ability, specifically measuring an individuals ability to access and retrieve semantic information (memory) as a component of executive function. Category fluency is scored by number of correct words plus errors in a 60 second trial in each of 3 categories. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Category Switching scores will be used to measure cognitive control of verbal ability, specifically measuring an individuals ability to access and retrieve semantic information (memory), switching back and forth between 2 different semantic categories, a component of executive function. Category switching is scored by number of correct words plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Category Switching Accuracy scores will be used to measure cognitive control of verbal ability, specifically measuring an individuals ability to inhibit incorrect or repetitive semantic information (memory), while switching back and forth between 2 different semantic categories, a component of executive function. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Letter Fluency, first interval scores will be used to measure cognitive control of lexical processing, specifically measuring an individuals ability to retrieve phonemic information, a component of executive function. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. There are four intervals of this task the first assessing initiation of retrieval while the following trials measuring the ability to sustain retrieval. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of lexical processing.

DKEFS Letter Fluency, second interval scores will be used to measure cognitive control of lexical processing, specifically measuring an individuals ability to retrieve phonemic information, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to sustain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of lexical processing.

DKEFS Letter Fluency, third interval scores will be used to measure sustainment of cognitive control of lexical processing, specifically measuring an individuals ability to continue to retrieve phonemic information after multiple trials, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to maintain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior sustainment of cognitive control of lexical processing.

DKEFS Letter Fluency, fourth interval scores will be used to measure sustainment of cognitive control of lexical processing, specifically measuring an individuals ability to continue to retrieve phonemic information after multiple trials, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to maintain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior sustainment of cognitive control of lexical processing.

Participants with a history of Roux-en-Y gastric bypass, but without a diagnosis of hypoglycemia, or symptoms of hypoglycemia, recruited by advertisement flyers at postoperative surgical clinics at local hospitals (such as Brigham and Women's and Beth Israel Deaconess Hospitals), research match, and from other hypoglycemia studies at Joslin.

Cognitive Assessment (not diagnostic): Cognitive testing will assess premorbid intelligence, working memory and attention, verbal memory and delayed memory, executive function, and psychomotor speed.

ECG: ECG will take place during screening visit.

Total of all reporting groups

Northeastern United States

Patient Health Questionnaire-2 (PHQ-2) scores were used to measure depressive symptoms. Scores for this assessment range from 0 to 6, with a higher score indicating greater severity of depressive symptoms.

Beck Depression Inventory scores were used to measure depressive symptoms. Scores for this assessment range from 0 to 63, with a higher score indicating greater severity of depressive symptoms.

Alcohol Use Disorders Identification Test (AUDIT-C) scores were used to measure alcohol use. Scores for this assessment range from 0 to 10, with a higher score indicating more alcohol use.

Participants with a history of Roux-en-Y gastric bypass, but without a diagnosis of hypoglycemia, or symptoms of hypoglycemia, recruited by advertisement flyers at postoperative surgical clinics at local hospitals (such as Brigham and Women's and Beth Israel Deaconess Hospitals), research match, and from other hypoglycemia studies at Joslin.

Cognitive Assessment (not diagnostic): Cognitive testing will assess premorbid intelligence, working memory and attention, verbal memory and delayed memory, executive function, and psychomotor speed.

ECG: ECG will take place during screening visit.

RAVLT 20 minute recall accuracy scores, was used to measure delayed memory and was compared between groups. Scores for this assessment range 0 to 15, with a higher score indicating less delays in memory. Wilcoxon rank-sum tests was used to examine differences between groups.

Letter-Number Sequencing subtest from the Wechsler Memory Scale III scaled scores were used to measure working memory and were compared between groups. Wilcoxon rank-sum test was used to examine differences between groups. Scores for this assessment range 1 to 19, with a higher score indicating a superior working memory.

Delis-Kaplan Executive Function System (DKEFS),Trail Making Task score was used to assess the cognitive flexibility component of executive function. Scores are derived from time to complete the task plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive flexibility.

DKEFS Color-Word Interference Test (CWIT) Inhibition Switching scores was used to measure the cognitive flexibility component of executive function. The CWIT is scored by time to complete plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive flexibility.

DKEFS CWIT scores was used to measure the inhibition component of executive function. The CWIT is scored by time to complete plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior inhibition.

DKEFS Letter Fluency Task will be used to assess the verbal functioning cognitive control ability component of executive function. Scores are derived from the number of unique, correct words. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior verbal functioning cognitive control ability.

The grooved pegboard test is a manipulative dexterity task that assesses psychomotor speed, fine motor control, and rapid-visual motor coordination. Participants were asked to insert 25 grooved pegs into holes within the given time limit up to 300 seconds (the score upper limit is thus 300). Time taken to complete the test has been found to be inversely correlated with cognitive ability; therefore, a higher score represents an inferior score. Wilcoxon rank-sum test was used to examine differences between groups.

DKEFS Category Fluency scores were used to measure cognitive control of verbal ability, specifically measuring an individuals ability to access and retrieve semantic information (memory) as a component of executive function. Category fluency is scored by number of correct words plus errors in a 60 second trial in each of 3 categories. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Category Switching scores will be used to measure cognitive control of verbal ability, specifically measuring an individuals ability to access and retrieve semantic information (memory), switching back and forth between 2 different semantic categories, a component of executive function. Category switching is scored by number of correct words plus errors. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Category Switching Accuracy scores will be used to measure cognitive control of verbal ability, specifically measuring an individuals ability to inhibit incorrect or repetitive semantic information (memory), while switching back and forth between 2 different semantic categories, a component of executive function. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of verbal ability.

DKEFS Letter Fluency, first interval scores will be used to measure cognitive control of lexical processing, specifically measuring an individuals ability to retrieve phonemic information, a component of executive function. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. There are four intervals of this task the first assessing initiation of retrieval while the following trials measuring the ability to sustain retrieval. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of lexical processing.

DKEFS Letter Fluency, second interval scores will be used to measure cognitive control of lexical processing, specifically measuring an individuals ability to retrieve phonemic information, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to sustain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior cognitive control of lexical processing.

DKEFS Letter Fluency, third interval scores will be used to measure sustainment of cognitive control of lexical processing, specifically measuring an individuals ability to continue to retrieve phonemic information after multiple trials, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to maintain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior sustainment of cognitive control of lexical processing.

DKEFS Letter Fluency, fourth interval scores will be used to measure sustainment of cognitive control of lexical processing, specifically measuring an individuals ability to continue to retrieve phonemic information after multiple trials, a component of executive function. There are four intervals of this task the second through fourth trial assess ability to maintain retrieval. Participants are asked to name as many words a they are able starting with a specific letter, without repetition. Wilcoxon rank-sum test was used to examine differences between groups. Normative scores for this assessment range 1-19 (mean of 10, and standard deviation of 3), and a higher score indicates superior sustainment of cognitive control of lexical processing.

Participants with a history of Roux-en-Y gastric bypass, but without a diagnosis of hypoglycemia, or symptoms of hypoglycemia, recruited by advertisement flyers at postoperative surgical clinics at local hospitals (such as Brigham and Women's and Beth Israel Deaconess Hospitals), research match, and from other hypoglycemia studies at Joslin.

Cognitive Assessment (not diagnostic): Cognitive testing will assess premorbid intelligence, working memory and attention, verbal memory and delayed memory, executive function, and psychomotor speed.

ECG: ECG will take place during screening visit.