1. INTRODUCTION:

The human voice is not merely a means of verbal communication—it is a core aspect of personal identity, social interaction, and emotional expression. A voice loss can profoundly affect a person’s self-image, confidence, and ability to engage with others. Throat cancer, particularly laryngeal carcinoma, poses a significant threat to this vital human function. It is one of the most common head and neck cancers globally, especially among individuals with a history of smoking, alcohol use, or HPV infection.

When cancer affects the larynx extensively, total laryngectomy—the complete surgical removal of the voice box—is often the only curative treatment option. While this procedure can be life-saving, it comes at the cost of permanent loss of natural voice, along with changes in breathing and swallowing. The absence of vocal cords means that airflow no longer passes through the glottis to generate sound, thus requiring alternative voice restoration strategies to help patients regain the ability to speak¹.

Several methods have been developed for post-laryngectomy voice rehabilitation, including esophageal speech, tracheoesophageal puncture (TEP) with a voice prosthesis, and the use of external artificial larynx devices (electrolarynx). Among these, the artificial larynx stands out due to its ease of use, non-invasive nature, and widespread availability, especially in settings where surgical or advanced prosthetic options are not feasible.

Over the past few decades, artificial larynx devices have undergone significant improvements in terms of design, usability, voice quality, and digital integration. From early mechanical models with robotic voice tones to modern electrolarynxes that allow for pitch variation and hands-free operation, the field has seen continuous technological refinement aimed at improving both speech intelligibility and user satisfaction.

This review aims to provide a comprehensive overview of the history, types, technological advancements, limitations, and future directions of artificial larynx devices. It also discusses their role in the overall context of voice rehabilitation in laryngectomized patients, highlighting their clinical relevance, patient outcomes, and the need for ongoing innovation to better replicate natural human speech².

2. Background: Throat Cancer and Voice Loss.

2.1 Overview of Laryngeal Cancer:

Laryngeal cancer is a type of head and neck malignancy that arises from the tissues of the larynx, or voice box. It is classified based on the site of origin: glottic (vocal cords), supraglottic (above the vocal cords), or subglottic (below the vocal cords). Among these, glottic carcinoma is the most common and often presents early due to hoarseness of voice, enabling earlier diagnosis compared to other head and neck tumors.

The primary risk factors for developing laryngeal cancer include:

· Tobacco use (both smoking and chewing).

· Excessive alcohol consumption.

· Human papillomavirus (HPV) infection.

· Prolonged exposure to asbestos or industrial chemicals.

· Poor nutrition.

· Gastroesophageal reflux disease (GERD).

The incidence of laryngeal cancer has declined in some countries due to public health efforts to reduce tobacco use; however, it remains a significant concern, particularly in developing regions. Men are more commonly affected than women, and most cases occur in individuals over the age of 60.

Treatment Options Vary Depending on the Stage and Location of the Cancer But May Include:

· Radiation therapy for early-stage tumors.

· Chemoradiotherapy for organ preservation.

· Surgical resection, including partial or total laryngectomy, for advanced-stage disease.

When the tumor is extensive or resistant to chemoradiation, total laryngectomy becomes the treatment of choice. While this procedure is life-saving, it leads to permanent anatomical and functional changes, most notably the loss of natural voice³.

2.2 Impact of Laryngectomy on Speech:

Total laryngectomy involves the complete removal of the larynx, including the vocal cords, resulting in the separation of the airway and the digestive tract. After surgery, the trachea is redirected to a stoma (opening) in the neck for breathing, and the natural airflow through the vocal cords—which is essential for speech production—is permanently eliminated.

As a consequence, patients lose their ability to speak using their natural voice, profoundly affecting their:

· Verbal communication

· Social interaction

· Professional life

· Emotional well-being

Many patients experience depression, anxiety, and social isolation after surgery due to their inability to express themselves effectively⁴.

To Address This, Various Voice Rehabilitation Strategies Have Been Developed, Including:

1. Esophageal Speech:

This technique involves "swallowing" air into the esophagus and releasing it to create sound. While it is cost-free and hands-free, only a small percentage of patients (~20–30%) can master this technique due to the complex coordination required.

2. Tracheoesophageal Puncture (TEP):

Considered the gold standard in voice rehabilitation, TEP involves the surgical creation of a fistula between the trachea and esophagus, through which a voice prosthesis is placed. Air from the lungs is redirected into the esophagus to vibrate the pharyngoesophageal segment and produce speech. While it offers more natural-sounding voice, it requires surgical intervention and regular prosthesis maintenance.

3. Electrolarynx (Artificial Larynx):

An external handheld device that generates vibrations transmitted through the tissues of the neck or oral cavity. The user articulates these vibrations into intelligible speech using mouth and tongue movements. Electrolarynxes are widely used due to their non-invasive nature, ease of use, and immediate speech restoration (Eadie & Doyle, 2005)⁵.

Each method has its advantages and limitations, and the choice depends on patient preference, physical condition, anatomy, surgical history, and socioeconomic factors. However, the electrolarynx remains an essential voice restoration tool, especially in resource-constrained environments or when other methods are not feasible.

Furthermore, the psychological impact of voice loss cannot be understated. Patients often describe their altered voice as "robotic" or "inhuman," and the process of adapting to a new voice is complex. Therefore, early counseling, speech therapy, and the availability of user-friendly voice aids are critical for a successful post-laryngectomy recovery.

3. Evolution of Artificial Larynx Devices:

3.1 Early Devices:

Initial devices such as the Cooper-Rand electrolarynx were hand-held and produced monotonic, robotic voices. Although effective in restoring speech, they lacked the ability to convey natural emotion or intonation.

3.2 Limitations:

These early devices were bulky, required neck contact, and produced mechanical noise, which could lead to self-consciousness in users.

4. Classification of Artificial Larynx Devices:

Voice rehabilitation following total laryngectomy is critical for restoring a patient’s quality of life. Artificial larynx devices, broadly categorized based on their operating mechanism and placement, offer various options depending on the patient's physiological condition, usability preference, and affordability. These devices are mainly classified into three types: electrolarynx, pneumatic devices, and intraoral devices⁶.

4.1 Electrolarynx:

The electrolarynx is the most widely used type of artificial larynx. It is a small, hand-held battery-powered device that produces vibrations. When placed against the neck or under the chin, it transmits mechanical vibrations through the soft tissues, which the user modulates with articulatory movements (tongue, lips, jaw) to produce intelligible speech.

These devices typically contain a tone generator and allow for pitch and volume control. Some modern versions also provide digital pitch modulation, giving the user slightly more natural intonation. Brands like Servox Digital, TruTone, and Solatone have incorporated features like variable pitch, hands-free use, and rechargeable batteries⁷.

Advantages:

· Easy to learn and operate.

· Available in most clinical settings.

· Non-invasive and cost-effective.

· Immediate speech restoration post-surgery.

Limitations:

· Robotic or monotone voice.

· Requires intact tissue for effective transmission.

· Must be held by hand or strapped (unless hands-free).

Recent developments in Bluetooth-enabled electrolarynxes offer wireless microphone integration and smartphone app control, improving usability in younger, tech-savvy patients (Patel & Roy, 2021)⁸.

4.2 Pneumatic Artificial Larynx:

Pneumatic devices represent a battery-free alternative that uses the patient’s exhaled air to produce vibrations. Air is diverted through a nosepiece or mouthpiece to vibrate a thin diaphragm or reed. The resulting vibrations are directed into the oral cavity where articulators shape the final speech sounds.

Though these devices were more common in earlier decades, they are now rarely used due to their bulky design and mechanical complexity. However, they still hold value in settings where electronic devices are impractical or not affordable.

Advantages:

· Battery-free operation.

· Simple mechanical design.

· No electrical interference issues.

Limitations:

· Requires controlled exhalation.

· Limited pitch and volume modulation.

· More cumbersome to wear and maintain.

· Difficult to use for patients with compromised lung function.

One of the oldest and most cited examples of a pneumatic device is the Tokyo Artificial Larynx, used widely in Japan until more modern devices became available⁹.

4.3 Intraoral Electrolarynx:

The intraoral electrolarynx addresses certain anatomical or surgical limitations seen in post-laryngectomy patients, such as fibrosis, post-radiation neck stiffness, or tissue scarring. In these cases, the traditional electrolarynx, which requires skin contact, becomes less effective due to poor vibration transmission.

These devices deliver sound directly into the mouth via a small plastic tube inserted between the lips or teeth. The vibration unit remains outside the mouth, while the sound travels through the oral tubing to be shaped into speech.

Advantages:

· Useful when neck placement is ineffective.

· Can be used even with thick or fibrotic neck tissue.

· Allows clearer transmission of sound in some patients.

Limitations:

· Tube may cause discomfort or hygiene issues.

· Interferes with natural lip movements.

· May not be suitable for long-duration speech.

Modern intraoral devices aim to improve comfort with soft, biocompatible tubing and lightweight sound drivers¹⁰.

5. Modern Technological Advances:

The evolution of artificial larynx technology in recent decades has been fueled by advancements in digital electronics, artificial intelligence (AI), miniaturized hardware, and patient-centered design. These innovations not only enhance speech intelligibility and acoustic quality but also improve patient comfort, portability, and aesthetics—factors that directly influence user satisfaction and long-term adoption.

5.1 Digital Electrolarynx:

The introduction of digital electrolarynxes marked a significant improvement over earlier analog model. Devices such as TruTone™ and Servox Digital allow users to dynamically modulate pitch and volume during speech, giving them greater control over intonation and emotional expression (Robbins et al., 2020)¹¹.

These devices typically feature pressure-sensitive buttons that vary frequency output based on finger pressure, simulating a natural rise and fall of pitch in speech. Digital processing also reduces the mechanical buzz often associated with analog models, resulting in clearer and more intelligible output.

Modern digital electrolarynxes are also:

· Lighter and ergonomically designed.

· Equipped with multiple pitch settings and memory storage.

· Rechargeable or battery-operated for portability.

· Compatible with both neck placement and intraoral use.

As patients become increasingly vocal about their needs, manufacturers are responding with customizable sound profiles, ensuring that the device can adapt to various cultural or linguistic preferences.

5.2 Hands-Free Communication:

A major limitation of conventional electrolarynx devices is the need to use one hand for operation, which can be inconvenient and socially stigmatizing. Hands-free electrolarynx systems are now available, often as wearable neckbands or voice-activated units, allowing users to speak without manual activation¹².

These wearable systems:

· Detect subtle vibrations or breath patterns to initiate speech

· Can be worn discreetly under clothing

· Provide aesthetic benefits, especially in social and professional settings

· Allow multitasking and natural conversation flow

Some devices incorporate infrared sensors, wireless foot pedals, or chin switches to facilitate activation, improving usability for elderly or physically impaired users . These innovations make the artificial larynx more accessible for a wider population, including those with physical disabilities or limited hand mobility.

5.3 Bluetooth and AI Integration:

The integration of Bluetooth connectivity has significantly expanded the functionality of modern electrolarynxes. Bluetooth-enabled devices can:

· Connect to mobile apps, allowing users or clinicians to adjust pitch, volume, and vibration strength

· Pair with wireless microphones, which can enhance sound input quality

· Record, store, and analyze speech patterns over time for therapeutic feedback

Moreover, AI-based speech enhancement algorithms are increasingly being used to filter out background noise, optimize vocal clarity, and adapt voice profiles based on the user’s preferences.This is particularly helpful in noisy environments such as public spaces or workplaces.

Additionally, mobile applications connected to the device can track daily usage, monitor device health, and even send data to the clinician for remote follow-up, allowing for more efficient post-operative care and adjustment¹³.

5.4 Smart Voice Simulation:

One of the most exciting areas of innovation is smart voice simulation—the use of acoustic modeling, machine learning, and deep neural networks to replicate human vocal attributes such as intonation, emotion, accent, and prosody (Ramya et al., 2023). These systems aim to produce voices that are nearly indistinguishable from natural speech.

Future systems may allow patients to:

· "Clone" their pre-surgery voice, using recorded samples and AI training.

· Adjust vocal tone for gender, age, or mood.

· Translate articulatory movements into high-fidelity audio in real-time.

· Access cloud-based voice backups or updates via internet connectivity.

These developments hold promise for more individualized and human-like voice restoration, addressing not just communication, but also the psychological aspects of identity and social reintegration after laryngectomy.

6. Biocompatible and Implantable Devices:

While external electrolarynxes provide substantial benefits, they are still visible, external, and require manual handling or attachments. This has driven research into implantable voice prostheses—devices surgically inserted into or around the tracheoesophageal or pharyngeal region that generate sound internally, offering a more natural, seamless solution.

6.1 Materials and Design:

Implantable devices are typically made from biocompatible, non-toxic, and durable materials such as:

· Medical-grade silicone.

· Titanium alloys.

· Polytetrafluoroethylene (PTFE).

· Polyurethane composites.

These materials are chosen for their:

· Resistance to corrosion or microbial growth.

· Flexibility and ease of surgical insertion.

· Long-term compatibility with human tissue.

· Minimal immune or inflammatory response.

Design innovations focus on minimizing device size while maximizing acoustic output and ensuring airtight sealing to prevent aspiration or infection.

6.2 Mechanism of Action

Unlike external electrolarynxes, implantable devices use:

· Subtle pressure changes from breathing or swallowing to initiate vibration.

· Embedded microcontrollers or piezoelectric elements to produce sound.

· Internal channels that direct the vibration toward the pharynx for modulation.

Some designs use electrical stimulation of residual laryngeal nerves or muscles to trigger sound production. Others integrate with TEP (tracheoesophageal puncture) pathways to deliver vibration into the pharyngoesophageal segment¹⁴.

6.3 Benefits and Limitations:

Benefits:

· No external components or visible hardware.

· Higher aesthetic appeal and self-confidence.

· Potential for long-term, low-maintenance speech generation.

· Reduced mechanical noise.

Limitations:

· Requires surgical implantation.

· Risk of device rejection, infection, or need for revision.

· Currently experimental and cost-intensive.

· Not suitable for all patient anatomies or tumor types.

6.4 Ongoing Research and Future Trends:

Several international research teams are exploring next-generation implantables using:

· 3D-printed anatomical models for custom fit.

· Battery-free piezoelectric systems powered by body movement.

· Bioelectronic sensors for automatic sound triggering.

· Nanocoatings to resist biofilm formation and improve hygiene.

The ultimate goal is to develop an invisible, natural-sounding, long-lasting voice restoration device that is personalized to each patient’s anatomy, lifestyle, and vocal history. If successfully commercialized, these devices could revolutionize speech rehabilitation for throat cancer survivors.

7. Biocompatible and Implantable Devices:

Implantable voice prostheses using biocompatible materials aim to remove external components and deliver a more natural voice. These are in experimental stages and offer hope for long-term integration without cosmetic compromise.

8. Comparison with Other Speech Restoration Methods:

Method	Advantages	Disadvantages
Oesophageal Speech	Natural-sounding, no device needed	Difficult to learn, short duration
TEP Voice Prosthesis	High-quality voice	Requires surgery, may cause leakage
Electrolarynx	Easy to use, accessible	Robotic sound, visible use

9. Psychological and Social Impact:

Despite technological advancements, electrolarynx users may experience social withdrawal due to the unnatural voice tone and device visibility. Counseling, speech therapy, and peer support significantly aid in psychological recovery¹⁵.

10. Future Trends and Research Directions:

The future of artificial larynx devices includes:

· 3D-printed prostheses tailored to patient anatomy.

· AI-based voice modulation for natural emotion expression.

· Neural voice control directly from brain signals.

· Battery-free devices powered by breathing or kinetic energy.

11. CONCLUSION:

The journey of artificial larynx devices has mirrored the evolution of modern biomedical technology—progressing from simple mechanical instruments to sophisticated, digitally-enhanced tools capable of restoring speech and dignity to patients who have undergone total laryngectomy. Over the past few decades, significant strides have been made in improving the usability, voice clarity, durability, and acceptability of these devices.

Initially, electrolarynxes were seen as last-resort options, often stigmatized due to their robotic tone and mechanical appearance. However, with advances in acoustic signal processing, user-controlled pitch modulation, and digital interface integration, these devices have become far more adaptable and user-friendly. Patients now have the ability to modulate tone, volume, and inflection, resulting in improved speech intelligibility and social confidence.

Despite these technological gains, the quest for a truly natural voice remains ongoing. Current artificial larynx devices, although functional, still fall short in replicating the rich, nuanced tonality of the human voice. The absence of emotion, prosody, and spontaneous vocal variation continues to impact the quality of interaction between patients and their listeners. Addressing this gap is crucial for restoring not just the physical ability to speak, but also the emotional and psychological aspects of communication.

Moreover, from a clinical standpoint, artificial larynxes offer an important voice rehabilitation tool that is non-invasive, low-cost, and readily available, especially in resource-limited settings where advanced surgical options like tracheoesophageal puncture (TEP) may not be feasible. In many developing countries, these devices remain the primary mode of post-laryngectomy voice restoration, emphasizing their continued relevance in global health.

The future of artificial larynx devices is promising. Ongoing research into neural-controlled speech systems, voice cloning through AI, and biocompatible implantable prostheses aims to bridge the gap between mechanical phonation and natural voice. The incorporation of machine learning algorithms can enable devices to adapt to individual user speech patterns over time, creating more personalized voice profiles. Some experimental prototypes are even exploring brain-computer interfaces (BCIs) to facilitate thought-controlled speech generation, which could redefine the future of voice rehabilitation altogether.

Equally important is the psychosocial aspect of artificial voice restoration. Patient-centric design—considering comfort, device aesthetics, social acceptability, and ease of use—will be critical in the next phase of innovation. Healthcare professionals, speech-language pathologists, engineers, and patients must work collaboratively to ensure these devices are not only technically sound but also emotionally empowering.

Interdisciplinary collaboration remains the cornerstone of progress in this field. The integration of engineering, speech science, oncology, rehabilitation therapy, and patient feedback has already brought remarkable improvements. Continued cross-sector engagement will be vital in developing next-generation solutions that blend functionality with human-centric design.

In conclusion, artificial larynx devices play a vital role in restoring communication and rebuilding lives following the trauma of laryngectomy. While current devices offer a practical means of speech, future innovations hold the potential to restore authentic voice, natural expression, and emotional nuance, enabling patients not only to speak—but to speak like themselves again. The mission ahead is not merely technological; it is deeply humanitarian, reaffirming the profound importance of voice in human existence.

Top 15 Artificial Larynx Devices (2025):

Servox Digital XL – ₹1,33,100 (~$790) Renowned digital electrolarynx with pitch/volume control, rechargeable batteries, long talk time, and belt pouch reddit.com+7tradeindia.com+7biggo.com+7reddit.com+15electrolarynx.com+15germanos-medicals.gr+15.

Labex Digital Electrolarynx – ₹36,445 (~$365) Affordable, lightweight, 9V rechargeable battery-powered, adjustable-tone model praised for ease-of-use amazon.com.

Blom‑Singer Digital Electrolarynx EL 1000 – ₹65,810 USB-rechargeable electrolarynx from Blom-Singer, trusted for clinical reliability brucemedical.com+1sourcifychina.com+1.

Extra Electrolarynx (custom pitch) – ₹55,375 Pressure-sensitive, fully customizable pitch control, excellent portability.

Romet Electrolarynx – ₹42,000 Indian-designed device with sturdy build and domestic repair support; widely used reddit.com+12tradeindia.com+12shopclues.com+12.

Provox TruTone EMOTE – ₹58,000–$1,373 Advanced pitch-modulating electrolarynx with USB charging and emotional tone function reddit.com+15diglo.com+15sourcifychina.com+15.

Provox TruTone Plus – ₹35,000–$846 Enhanced version with micro-USB charging and ergonomic design biggo.com.

Nu‑Vois III Digital – ₹44,000–$542 Compact, adjustable-tone digital device favored for its clarity and simplicity reddit.com+14diglo.com+14amazon.com+14.

Nu‑Vois I Electronic – ₹39,000–$482 Basic yet durable electrolarynx, ideal as backup or budget-friendly option reddit.com+14diglo.com+14amazon.com+14.

SolaTone Plus – ₹34,000–$658 Robust, user-friendly model often used in clinics and rehabilitation centers shopclues.com+15brucemedical.com+15germanos-medicals.gr+15.

Servox Digital (standard) – ₹100,000–$1,250 Flagship model with high-quality seamless speech, USB compatible germanos-medicals.gr.

Servox Inton – ₹65,000–$780 Intonation-enabled electrolarynx offering multi-tone control options diglo.com+4brucemedical.com+4germanos-medicals.gr+4.

Servox XL (US version) – ₹105,000–$995 Latest variant with modern power management, up to 50% extended battery life germanos-medicals.gr+2shop.assistivetechu.com+2electrolarynx.com+2.

Griffin Labs TruTone Plus – ₹70,000–$846 Single-button device with adjustable pitch and USB charging, compact and durable brucemedical.com+4biggo.com+4amazon.com+4.

EFI PiVoice (Japan Prototype) – ¥200,000+ (~₹1.2 L) AI-enhanced larynx prototype in trials, promising near-natural speech patterns.

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Received on 12.08.2025 Revised on 08.09.2025

Accepted on 27.09.2025 Published on 15.10.2025

Available online from October 30, 2025

Research J. Science and Tech. 2025; 17(4):288-296.

DOI: 10.52711/2349-2988.2025.00040

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Creative Commons License.