MUSKEGON, Mich. (WOOD) — A woman accused of abusing and murdering her teenage son will undergo a competency evaluation.

The evaluation for Shanda Vander Ark was ordered Wednesday, the day she was scheduled to be in court for a preliminary hearing.

Competency evaluations are used to determine whether defendants are capable of understanding the charges and court proceedings and assisting in their own defense, which is their right. The evaluations do not attempt to determine whether a defendant was sane at the time of the alleged crime. The process can take some time, so Vander Ark’s preliminary hearing has not yet been rescheduled.

Vander Ark, 43, is charged with open murder and first-degree child abuse in the death of her 15-year-old son Timothy Ferguson.

Timothy was found dead July 6 at the family’s home in Norton Shores. The medical examiner said he death was the result of multiple factors including malnutrition and hypothermia. Prosecutors say his mother and elder brother abused him, including withholding food and placing him in an ice bath the day before his death.

The brother, 20-year-old Paul Ferguson, is also charged with first-degree child abuse in the case.