Korsakoff's Syndrome - Symptoms

Symptoms

There are six major symptoms of Korsakoff's syndrome:

1. anterograde amnesia
2. retrograde amnesia, severe memory loss
3. confabulation, that is, invented memories which are then taken as true due to gaps in memory sometimes associated with blackouts
4. meager content in conversation
5. lack of insight
6. apathy - the patients lose interest in things quickly and generally appear indifferent to change.

These symptoms are caused by a deficiency of thiamine (vitamin B₁), which is thought to cause damage to the medial thalamus and mammillary bodies of the hypothalamus as well as generalized cerebral atrophy. These brain regions are all parts of the papez circuit, which is heavily in involved in emotion and memory.

When Wernicke's encephalopathy accompanies Korsakoff's syndrome, the combination is called the Wernicke-Korsakoff syndrome. Korsakoff's is a continuum of Wernicke's encephalopathy, though a recognised episode of Wernicke's is not always obvious.

Korsakoff's involves neuronal loss, that is, damage to neurons; gliosis which is a result of damage to supporting cells of the central nervous system; and hemorrhage or bleeding in mammillary bodies. Damage to the dorsomedial nucleus or anterior group of the thalamus (limbic-specific nuclei) is also associated with this disorder. Cortical dysfunction may have arisen from thiamine deficiency, alcohol neurotoxicity, and/ or structural damage in the diencephalon.

Originally it was thought that a lack of initiative and a flat affect were important characteristics of emotion. Studies have questioned this, proposing that it is not necessarily a symptom of Korsakoff’s. Research suggesting that Korsakoff patients are emotionally unimpaired has made this a controversial topic. It can be argued that apathy, which usually characterizes Korsakoff patients, reflects a deficit of emotional expressions, without affecting the experience or perception of emotion.

Korsakoff's Syndrome causes deficits in declarative memory in most patients, but keeps implicit spatial, verbal, and procedural memory functioning intact.

Research has also suggested that Korsakoff patients have impaired executive functions, which can lead to behavioral problems and interfere with daily activities. It is unclear however, which executive functions are affected most.

At first it was thought that Korsakoff patients used confabulation to fill in memory gaps. However, it has been found that confabulation and amnesia do not necessarily co-occur. Studies have shown that there is dissociation between provoked confabulation, spontaneous confabulation (which is unprovoked) and false memories. That is, patients could be led to believe certain things that haven’t happened, just like people without Korsakoff’s syndrome.