In a turnaround from December, a Baton Rouge charter school that serves students with dyslexia was granted an extension Tuesday by the state's top school board.

The school, Louisiana Key Academy, was criticized last month at the state Board of Elementary and Secondary Education, and BESE delayed a vote on its future.

However, BESE approved an extension Tuesday and also agreed that a new measuring stick will be used in the future to gauge how the school is performing.

"We are very pleased and thankful," said Dr. Laura Cassidy, president and chairwoman of the board that oversees the school and the wife of U.S. Sen. Bill Cassidy, R-Baton Rouge.

Students with dyslexia have trouble reading and recognizing words.

The school has about 300 students in grades one to five. It is one of just two such public schools in the state. The school got an F for its 2016 state-issued letter grade.

However, in the future it will be reviewed using what state officials call an alternate framework. That means students will take tests like their peers statewide, and get a school performance score that is converted into a letter grade.

But the new assessment means officials will also consider students served by the school, whether they are improving academically and other issues in deciding whether it remains in operation.

BESE also approved allowing Louisiana Key Academy to offer sixth grade classes next school year, so current students can stay another year.

The action ensures a fifth year of operation for the school, and then BESE decides whether to approve a longer-term renewal.

Last month state Superintendent of Education John White said the school did not meet conditions for an extension.

White recommended that Louisiana Key Academy get a probationary extension while officials crafted a rubric that will be used for future measurements.

Families previously opted out of the exams, and those results are typically the key factor in whether BESE grants charter extensions.

"The real goal is so that the children can read the written word," Laura Cassidy said Tuesday.

"It is one thing to have a test or a book read to you," she said "Our goal is for them to read on grade level by themselves."

School officials hope to eventually add classes through the eighth grade.

The same state assessment rules will apply to the other school that serves students with dyslexia – MAX Charter School in Thibodaux.

Before BESE gave final approval to the changes Tuesday Debbie Meaux, president of the Louisiana Association of Educators, questioned the move.

Meaux noted that school performance scores play a huge role in whether schools remain open. She said alternate frameworks, like those that will be used for Key Academy, should be applied to the special school district and other schools.

If not, Meaux said, "you risk the criticism of playing favorites."

In other action, BESE gave final approval to three charter schools like those that are the target of a lawsuit on how they are funded.

They are Baton Rouge University Preparatory, Collegiate Academies, also in Baton Rouge and Jefferson Chamber Foundation Academy in Lafayette.

A fourth school that won tentative approval Monday, Red River Charter Academy in Avoyelles Parish, failed on a 5-5 vote.

Follow Will Sentell on Twitter, @WillSentell.