Spoken Language Technology Takes on Dementia

The platform being developed at the Chinese University of Hong Kong aims to automate common assessment tests

4 min read
Image of a woman comforting an elderly gentleman.
Photo: iStockphoto

THE INSTITUTEDementia affects millions of people worldwide. There is no treatment, but an early diagnosis can help patients slow the progress of their symptoms. The condition can affect people’s mental function, behavior, and memory.

Because dementia can cause different patterns of damage to the brain, no single test can determine whether someone has it. Instead, doctors use several screening tools including in-person interviews, questionnaires about daily routines, and drawing assessments. The tests, performed by clinicians and other professionals, are done regularly to check for changes—which can become expensive.

IEEE Fellow Helen Meng, a professor of systems engineering and engineering management at the Chinese University of Hong Kong (CUHK), is working on a machine-learning platform to helpmake screening more accessible and less expensive. The platform likely will use data analytics, human-computer interaction, and spoken-language technology.

Hong Kong has a large aged population, Meng says, and dementia is on the rise. Although all the region’s citizens are covered by the public health care system, it can take a long time to get an appointment with a specialist, she says, so valuable time can be lost. She is working with other researchers at the university, including many IEEE members, to make assessments accessible through AI, and eventually give people the ability to do self-assessments.

“As a researcher, a lot of our efforts have been focused on advances in existing applications such as high-accuracy speech recognition,” Meng says, “but I want to look into using the technology for new applications such as detecting early signs of dementia. The way to catch dementia early is to do frequent assessments on an individual’s capabilities. If dementia can be detected earlier, intervention can be started sooner.”


One well-known exam that neurologists perform is the Montreal Cognitive Assessment. Designed to evaluate short-term memory, language ability, and attention span, it includes activities such as naming animals and drawing components of a clock. As with other such assessments, the Montreal test is still done on paper, and the results are not digitized.

The neurologist interviews patients and asks them to assess their memory and cognitive functions. The patients’ responses might be subjective, varying from day to day even if their abilities don’t.

Meng says machine learning and big data can help make those diagnoses more objective. Artificial intelligence algorithms and other technology could automatically analyze collected data.

In particular, spoken-language technology could be used to assess a person’s cognitive health and emotional state based on their speech.

 “We want to be able to identify spoken-language biomarkers that are indicative of neurocognitive disorders,” Meng says. “The reaction time after a question is asked could be recorded. For example, if there’s a lot of hesitation or pausing, even at millisecond intervals, these could be measured in an objective way using engineering approaches.”

Offering tests on a computer or recording people’s speech while they answer questions via a telephone could help reduce the number of needed visits to the doctor, Meng says. A clinical cognitive expert or neurologist would review the automated assessments.

“We don’t intend for our automated software to make decisions about whether someone has dementia,” she says. “Our objective is not to replace the clinicians. We look at AI as a decision-support tool.”

The project has recently been awarded the theme-based research scheme of Hong Kong’s Research Grants Council.  This is among the highest level of research funding in the region, according to Meng.

Image of Professor Helen Meng speaking during a lecture series at CUHK. Meng recently spoke on the topic of artificial intelligence and well-being as part of a lecture series at the Chinese University of Hong Kong.Photo: The Chinese University of Hong Kong


Meng, who grew up in Hong Kong, was accepted to medical school as well as MIT’s engineering program. She says she thought it would be a good experience to study abroad, so she attended MIT, where she earned bachelor’s and master’s degrees in electrical engineering. She also got a Ph.D. in electrical engineering and computer science there.

She joined the CUHK in 1998 and established its Human-Computer Communications Laboratory the following year. She founded the university’s Stanley Ho Big Data Decision Analytics Research Center in 2013 and serves as one of its directors.

She has collaborated on several biomedical engineering research projects with the doctors at Prince of Wales, the CUHK teaching hospital.


Meng joined IEEE in 1998, when she was an assistant professor. She served as reviewer and then associate editor for the IEEE Signal Processing Society’s Transactions on Audio, Speech, and Language Processing and eventually was elected editor-in-chief of the publication, serving in that capacity from 2009 to 2011. She was a member of the society’s board of governors and its nominations and appointments committee.

“IEEE is a global platform, so there are many ways to participate,” she says. “I’ve made quite a few friends and met colleagues around the world who are experts in their area. It has been a great experience.

“Membership also broadens one’s horizons. Through IEEE’s conferences and publications, you get to look beyond your own area of expertise.”

Meng works to increase the number of women in engineering. She and other women have spoken during the annual IEEE Signal Processing Society conference’s luncheon.

“We make sure that female keynote speakers are invited to conferences, not just men,” she says. “We need more gender diversity.”

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

This article appears in the February 2023 print issue.