| Data acquisition |
Windows app or memory card (no PC) |
Android app (high spec phone not required, IPhone version possible but no ETA) |
| Data extraction (to EDF) |
Windows app |
Windows command line tool (other versions possible, and also a possibility to move this to the Android app but no ETA) |
| EEG signal |
Provided by ZMax headband |
N/A. Recorded separately with ZMax if needed |
| Accelerometer signal |
Yes |
Yes |
| Noise level (snoring) |
From ZMax Total on-board sensor |
From mobile (better consistency) |
| Light meter |
From ZMax Total on-board sensor, no unit |
From mobile (better consistency regardless of head tilt, standardized to Lux) |
| Sensor technology |
Uses thermistors and an SpO2 sensor |
Also uses thermistors and an SpO2 sensor |
| SpO2 responsiveness |
Highly responsive SpO2 computation (beat by beat, no low pass filtering) |
Same highly responsive SpO2 computation (beat by beat, no low pass filtering) |
| SpO2 standardization |
Hypnodyne proprietary (not standardized) |
Industry standard pulse oximetry assembly |
| SpO2 DC component accuracy |
Slightly less accurate due to internal DC nulling logic (DAC driven) |
More accurate and configurable |
| SpO2 LED intensity |
Auto calibrates to optimize signal, always on when connected |
Auto calibrates but also configurable, can also be switched off to maximize battery life for respiration-only recordings |
| Sanitization & maintenance |
Slightly more difficult to sanitize; thermistor is accessible but recessed and not replaceable |
Easier to sanitize; thermistor extends away from the device and can be dipped in 99.8% alcohol, and can be replaced |
| Durability / fragility |
More fragile – bending hooks too much will damage the sensor |
Less fragile – thermistor includes the hooks and is replaceable |
| Sampling frequency |
85.33 Hz for both the thermistors and the light signal used for SpO2 computation |
25 Hz for the thermistors; 50 Hz for the light signal used for SpO2 computation |
| Connection / standalone use |
Separate sensor that plugs into the ZMax headband; requires ZMax Total |
Fits on the nose without connection to ZMax; can operate as a completely standalone device |
| Comfort |
Less comfortable – wires run across the nose down to the nostrils |
Supremely comfortable; weighs only a few grams; almost no tactile sensation once applied |
| Battery life |
Higher and limited by ZMax battery life (~11 hours on a new, fresh battery) |
Lower and with own dedicated battery (~16 hours); SpO2 can also be disabled for airflow-only recordings extending life to >24 hours or longer |
| Sync with EEG |
Thermistor/SpO2 data is sample-by-sample synced to ZMax data (e.g. the EEG channels) when used with ZMax Total |
Separate device operating via Bluetooth; not natively sample-synced |
| Basic synchronization method |
N/A – inherently synced |
Switch on both devices at the same time; expect ~1–2 seconds of connection delay; theoretical clock deviation over a full night is a further ~2 seconds |
| Movement-based sync |
N/A |
Both devices have an accelerometer; shaking the head three times at the start and end of a recording provides a reference of simultaneity |
| Advanced software sync |
N/A |
AirMax can connect to the ZMax TCP/IP server (HDServer) and stores a synchronization text file for near-perfect post-processing alignment of the two recordings |
