When Senator Mitch McConnell had a sudden change in mental status while delivering remarks on Capitol Hill, he seemed frozen in time and unresponsive for about 30 seconds. He was experiencing a neurological event called an altered or sudden change in mental status. Although the senator’s aides blamed the episode on just being overtired, some medical experts questioned why the senator wasn’t taken to the hospital for observation and a mental status exam.

The phrase mental status refers to a global assessment of a person’s cognitive and behavioral state. When mental-health providers do a global assessment of functioning (GAF), they look at three major areas of function: social, occupational, and psychological. The GAF attempts to quantify a person’s overall functioning with a score ranging from 1 to 100. The lower the score, the worse the function. A mental status exam is a formal examination that considers several factors, including mood, mental and physical functioning, clarity of thought, orientation, speech, ability to use language, judgment, and memory.

A sudden change in mental status often refers to a sudden loss of usual functioning due to a change in one or more of these areas. A change in mental status may also be accompanied by a loss in physical functioning.

The press described the senator’s change in mental status as blanking out or freezing. When physicians refer to freezing, they are describing an episode in which the patient is unable to act. It could be an episode of silence or staying motionlessness or very still while staring into space.

Episodes of freezing may also be accompanied by symptoms of sudden change in mental status, such as confusion, severe anxiety, and disorientation.

Freezing can cause loss of speech, as happened with the senator. The inability or unwillingness to speak is referred to as mutism. Mutism can have many causes, such as severe anxiety, called selective mutism, or involuntary loss of speech due to an inability to emotionally process a traumatic event. Aphasia is another medical term for loss of ability to speak or understand speech. Aphasia is usually used to describe a physical rather than an emotional cause.

Many possible causes

While the cause of Senator McConnell’s sudden change in mental status is unknown, there are many possibilities.


  • Brain injury or diseases. About four months before his sudden change in mental status, the senator had suffered a severe fall causing broken ribs and a concussion. A concussion is a traumatic brain injury that affects your mental status. Brain injury can result in temporary or permanent disability. A brain injury from a stroke, for instance, can permanently affect the speech centers of the brain.

Chronic degenerating brain diseases such as Parkinson’s disease and related illnesses like amyotrophic lateral sclerosis, multiple sclerosis, or Alzheimer’s disease can also be associated with freezing. In people with Parkinson’s disease, freezing is commonly seen in patients with advanced disease. Patients may find themselves suddenly but temporarily unable to move or speak for a few seconds to a few minutes. The patient is typically aware of the deficits. Although the freezing goes away, other Parkinson’s symptoms persist.


  • TIA. Mental health experts speculated that a transient ischemic attack (TIA) or seizure could be possible causes. A TIA causes temporary stroke symptoms due to a brief disruption of blood flow to the brain. The symptoms are limited to the parts of the body controlled by the affected brain area. Typical symptoms include weakness or numbness on one side of the body affecting the face, arm, or leg, loss of vision, loss of the ability to speak or to speak clearly, or sudden dizziness. A TIA lasts a few minutes, and the patient may or may not be aware of the deficit. A considerable percentage of patients who experience a TIA eventually go on to develop a stroke.


  • Seizures. A type of seizure called an absence seizure is caused by abnormal electrical activity in the brain, resulting in a temporary loss of consciousness. An observer may note that the person has suddenly stopped their usual movement for 10 to 30 seconds, can’t speak, but can stand without falling, and is manifesting some simple repetitive motor movements such as lip smacking, chewing, small hand movements, or fluttering eyelids. The person typically reverts to normal functioning without awareness of the event.

Emergency evaluation

Although there are many causes of freezing and blanking out, any sudden and new change in mental status is a red flag for a serious problem. Freezing is seen in a broad range of psychiatric, medical, and neurologic diseases and requires a comprehensive evaluation to determine the underlying cause. There are serious and less serious causes of freezing, some of which are recurrent, while others are restricted to a single episode.

Even for a skilled observer, like a neurologist, psychiatrist, or emergency physician, it is usually not possible to know the cause of freezing without additional information from testing and a physical examination.

The examination includes a thorough review of the events leading to the episode, as well as details about the areas of disability and time course of the symptoms. In many cases, the most valuable information comes from someone who had observed the event. For example, Senator McConnell could not tell what happened to him or how long it lasted but many observers could.

A neurological examination of sensory (sensations and feeling) and motor (movement and strength) systems can identify any remaining symptoms or deficits. The findings in a routine physical examination may help the doctor’s understanding of possible causes, and a careful psychiatric evaluation can clarify if there are underlying emotional or behavioral issues complicating or causing the episodes of freezing.

With the data from these evaluations, a physician can identify which, if any, of the many available tests and studies would be appropriate to further confirm a cause of the episodes.

Important tests to evaluate altered mental status include brain imaging studies, electrocardiograms (EKG), and electroencephalograms (EEG), which is the best test for seizure. The best treatment depends on finding the right cause.

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