The photos are too small to narrow-down a diagnosis, but conditions that usually stress indoor tropical plants in winter are insufficient light, humidity levels that are too low, or being close to a draft (either warm or cold). It can also arise from over- or under-watering, and it can be difficult to tell which between those extremes it is, since the resulting symptoms can look the same. Try to gently remove the plant from the pot to look at any roots that have reached the edges of the soil mass. If they are firm, even if they are stained a bit brownish by the potting soil, they may be okay. If some are soft and squishy, pulling apart easily and often being dark in color, they may have rotted by staying too wet at some point. This type of Anthurium isn't too sensitive about staying moist, but like many indoor plants, it does best when allowed to get fairly dry to the touch at least an inch deep into the container between waterings. If it sits on a saucer, make sure the collected water after the pot drains is emptied so the pot doesn't sit in the water and reabsorb it.

We can't see how close it is to a sunny window, but direct sun in front of a window during winter is not too intense for houseplants, even if they are not sun-loving species. The further a plant gets from a light source like a sunny window (even as little change as moving it a foot further away, or off to the side of the window frame), the dimmer the light it can collect for photosynthesis, and if it can't make and store enough energy to sustain all of the leaves it has, some will be shed, usually turning yellow and/or brown and dry in the process.

You can examine the undersides of the leaves for any pests, but they would be visible if present and numerous enough to be triggering this type of yellowing and leaf loss. The pattern of leaf discoloration does not look like what we tend to see with spider mite or insect issues. If it's an infection (other than root rot), there is no remedy, but leaves that get too degraded can be clipped off. Otherwise, try to keep the leaves since much of the leaf area that's green is still functioning photosynthetic tissue and providing the plant with energy.

For now, just try to keep the plant within a foot or so of a sunny window (though away from a cold draft, if it's a leaky window). Even if it declines a bit further (areas of the leaves that have turned yellow or brown cannot green-up again, even if the plant stabilizes), there may be enough resources stored in the roots and main central stem (if it has one) for the plant to rebound once moved outside again in late spring.

Miri